Asian Forum for Accelerators and Detectors 2024

17 Apr 2024, 01:30 → 19 Apr 2024, 20:00 Asia/Taipei

The Asian Forum for Accelerators and Detectors (AFAD) in 2024 will be hosted by National Synchrotron Radiation Research Center (NSRRC), in Hsinchu, Taiwan, R.O.C. AFADs are held annually under the guidance of Asian Committee for Future Accelerators (ACFA) to promote collaboration among universities and research institutes in Asia and Oceania.

The major topics (working groups) of the Forum are:
WG1: Accelerator and its related technologies for photon science
WG2: Detector technology development
WG3: Accelerator technologies for industrial & medical applications
WG4: Innovative accelerator techniques
WG5: Accelerator and its related technologies for hadron (neutron) science
WG6: Network & computing
WG7: Cryogenics, cryomodule and superconducting technology for accelerators

 

 

Official Sponsor

 

Sponsors

 

Organizer

AFAD2024_Poster.pdf airport_car_service_reservation_form_AFAD2024.pdf

Accommodation

• Asian Forum for Accelerators and Detectors (AFAD-2024).pdf
• Lakeshore Hotel-Metropolis(reservation-form)-AFAD-2024.pdf
• NSRRC Guesthouse application form.doc

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Wednesday, 17 April

08:00 → 09:00 Registration

09:00 → 09:55 Opening and Plenary talk

Chair: Wai-Keung Lau, NSRRC

09:00 Opening talk

Speaker: Chia-Hung Hsu (NSRRC)

09:15 Status and prospect of KEK

KEK is a research institute in Japan carrying out basic science research in a wide range of scientific fields from particle and nuclear physics to materials and life sciences using large accelerator facilities. KEK’s research facilities are open to international science communities. Three on-going projects are SuperKEKB/Belle II and Photon Factory at the Tsukuba campus and J-PARC at the Tokai campus, a joint project between KEK and Japan Atomic Energy Agency. KEK is also making efforts to prepare for future projects such as the International Linear Collider(ILC). There are many progresses in J-PARC(750kW), SuperKEKB and ILC. Current status and future prospects of research activities at KEK is described in the talk.

Speaker: Shoji Asai (KEK)

10:00 → 10:10 Group photos

10:10 → 10:30 *The coffee break for WG4 shall be 10:10~10:30

10:10 → 11:00 Coffee Break

10:40 → 11:20 WG4

10:40 Fast electron generation and transport studies in relativistic laser-thin foil interactions at RRCAT

Relativistic fast electrons are generated in the interaction of ultrashort (tens of fs) ultrahigh intensity laser (>1018W/cm2) pulses with solid target.Investigation of thegeneration and transport of fast electrons in solid material is a subject of intense research investigation not only for fundamental understanding of laser matter interaction in extreme condition but also for various potential applications including laser driven fast ignition approach of laser fusion, MeV proton and ion acceleration, creation of ultrashort x-ray sources and warm dense matter.
At Laser Plasma Division, RRCAT, Indore, India, we have carried out the experimental studies on the generation and transport of fast electrons in intense ultra-short laser foil interaction using high-power (150 TW, 25 fs) Ti:sapphire laser in the intensity regime of ~1018 - 7x1019W/cm2. Investigations involved both direct measurement of fast electrons as well as indirect measurement using K x-rays and hard x-rays emitted during interaction.A clear signature of JB acceleration in oblique incidence laser interaction with foil target was demonstrated through the observation of fast electron beam along laser direction.We also observedstrong polarization dependence of JB acceleration on fast electron flux. The possible mechanism was studied by varying the preformed plasma scale length in front of the solid target. We demonstrated super ponderomotive acceleration at longer scalelength whereas the fast electron temperature was much lower than the ponderomotive scaling. Next, we studied the transport of fast electrons through dense solid through K x-ray line radiation measurement using indigenously developed HAPG crystal spectrograph and2D high resolution monochromatic imaging usingspherically bent quartz crystal spectrograph. In particular, refluxing of fast electrons due to excitation of electrostatic sheath field and fast electron divergence angle inside solid to infer therole of self-generated magnetic fields on collimating fast electrons at such high laser intensity was investigated. In this talk details of the investigations performedand physical understanding of the processes involved will be presented.

Speaker: Dr Vipul Arora (Raja Ramanna Centre for Advanced Technology, Indore)

Vipul Arora AFAD prsentation WG 4_1.pptx

11:00 Plasma-based acceleration studies in IHEP

During the last few years, IHEP plasma-based acceleration study group dedicated its time on both laser wakefield acceleration (LWFA) and plasma wakefield acceleration (PWFA).
In LWFA, we mainly focused on injection mechanism studies to improve the beam quality. Different injection schemes such as scissors-cross ionization injection, coaxial laser interference induced injection, tightly focused laser injection will be introduced in this presentation.
In PWFA, we mainly studied on plasma injector for circular electron positron collider (CEPC). Low-field dipole magnet problem in the booster ring of is one of the most important problems in CEPC that need to be addressed. One prospective method is to add a few tens meter long plasma accelerator, named “CEPC plasma injector” (CPI), to increase the electron/positron energy from 10 GeV to 30 GeV, and then inject them to the booster ring. We started CPI studies since 2017 and made a great progress in the recent years. In this talk, I’ll show the simulation studies on hosing instability for high transformer ratio (HTR) PWFA, high quality positron acceleration in PWFA, electron RF guns and linac, etc.
At last, I’ll introduce 2 PWFA test facility proposals in IHEP and their recent progress.

Speaker: Dazhang LI (IHEP, CAS)

11:20 → 12:20 WG1

Chair: JuiChe Huang, NSRRC

11:20 Preliminary lattice design for Australian Synchrotron 2.0

A new project is underway to develop the successor to the current Australian Synchrotron. The new storage ring is proposed to be 450 m in circumference operating at 3 GeV. A preliminary 7BA lattice has been designed which utilises the higher-order achromat (HOA) scheme to suppress strong sextupole driving terms. The lattice has 24 sectors and a natural horizontal emittance of 50 pm-rad. This is achieved using a combination of strong combined function magnets and reverse bending magnets in the unit cell, as well as careful tuning of the bending angles to preserve positive momentum compaction factor. The dynamic aperture, momentum aperture and Touschek lifetime have been optimised by tuning the linear optics and sextupole strengths with a multi-objective genetic algorithm.

Speaker: Xuanhao Zhang (Australian Synchrotron)

2024.04.17 AFAD24 - AS2.0 FZhang.pptx

11:40 On-line bunch-by-bunch position and synchrotron phase monitoring and its study at the Taiwan Photon Source

The online bunch-by-bunch position and phase monitor has been established by employing a high-speed analog-to-digital converter, meticulously synchronized with the accelerator's radio frequency. I/Q demodulation is utilized in the phase monitor to calculate the beam phase. To unravel the intricacies of bunch motion, independent component analysis has been employed, efficiently segregating the bunch motion into discrete sources. The resulting bunch motion is a direct outcome of the linear combination of these distinct sources, significantly simplifying the overarching data analysis procedure. An examination of the tune variation in these sources is conducted through a numerical analysis of fundamental frequencies. These monitors are used to study the bunch motion during injection, transient beam loading effects at various beam currents, and synchronous motion during routine operation.

Speaker: Chih-Hsien Huang (NSRRC)

BByB_20240416_upload.pptx

12:00 Laser-Compton X-ray generation stabilization at KEK LUCX facility by Digital LLRF phase&amplitude feedforward implementation into RF system

KEK LUCX facility is a normal conductive multi-bunch electron linear
accelerator devoted to develop an intense monochromatic source of laser-Compton
X-ray for monochromatic X-Ray imaging. In order to perform samples
tomography, stable laser-Compton X-ray beam is necessary. From accelerator side,
laser-Compton X-ray generation stability is basically defined by electron beam
parameters stability, while these parameters depend on accelerating field phase and
amplitude. Therefore, the stabilization of accelerating field is a milestone to
generate stable X-ray. Digital LLRF phase and amplitude feedforward system was
developed, tested and implemented into KEK LUCX facility RF system for the
accelerating field precise control.
This research presents results of electron beam parameters stabilization at
KEK LUCX facility. These parameters are beam average energy, energy spread
(RMS), bunch charge, beam arrival time, transverse normalized emittance. Also,
Digital LLRF feedforward system technical details are explained.

Speaker: Dr KONSTANTIN POPOV (High Energy Accelerator Research Organization (KEK))

AFAD_2024_POPOV_Konstantin_WG_01.pdf AFAD_2024_POPOV_Konstantin_WG_01.pptx

11:20 → 12:20 WG3

Chair: Anatoly Rozenfeld, University of Wollongong

11:20 Present status of a compact superconducting accelerator for heavy-ion therapy.

National Institutes for Quantum Science and Technology (QST, successor organization of National Institutes for Radiological Science) started carbon ion particle therapy in 1994.
Based on positive clinical results, carbon-ion radiotherapy was authorized as a Highly Advanced Medical Technology by Japanese government from 2003 and treatment for some kinds of cancers was applied to Japanese National Health Insurance system from 2016.
In addition, developments of compact accelerator for widespread use of carbon-ion radiotherapy was conducted from 2004. As a results, five facilities based on these studies were constructed in Japan and several abroad.
However, construction is limited to universities and large hospitals, and downsizing of accelerator is needed for more widespread use. Therefore, a new project, so called “Quantum Scalpel”, has been launched for development of more compact accelerator. In this project, a synchrotron will be downsized using combined-function superconducting magnets for main dipoles. At present, construction of a compact superconducting synchrotron is currently underway. In this presentation, the outline and present status of the project and R&D results of the superconducting synchrotron are presented.

Speaker: Shunya Matsuba (National Institutes for Quantum Science)

11:40 Development of silicon radiation detectors for therapeutic and space applications

Centre for Medical Radiation Physics at University of Wollongong has long history of development of the silicon radiation detectors for dosimetry in X-ray and particle radiation therapy. Overview of the developed pixelated Si detectors and their applications for high spatial and temporal resolution dosimetry on medical linac and on proton and heavy ion therapy will be presented.

Progress in development of SOI detectors for microdosimetry and their application for RBE study of the proton and heavy ions therapeutic beams in clinical setting will be demonstrated.

Another application of SOI microdosimeter is for evaluation of radiation shielding and radiation protection of astronauts in radiation environment typical for SPE and GCR. We demonstrated that SOI microdosimeters are suitable for in situ evaluation of radiation shielding efficiency of multi-layered space craft and astronaut shelter walls in radiation fields on accelerators mimicking SPE and GCR. Comparison of SOI microdosimeters with Timepix detector for biologically relevant dosimetry for astronauts radiation protection in GCR environment will be presented.

SOI microdosimeters have found application for wide range LET verification of ions on accelerators for Single Even Effect (SEE) studies in microelectronics including at CERN for high LET ions like 1GeV/u Pb. Development of Si sensors for displacement damage monitoring of space electronics will be discussed.

Speaker: Prof. Anatoly Rosenfeld (CMRP, School of Physics, University of Wollongong, Australia)

12:00 The introduction of the proton FLASH experiment beam line in CGMH

Jyun-Wei Jheng1, Shih-Yao, Chiou1, Tsz-Yui Chan2, Sen-Hao Lee3, Tsi-Chian Chao1,2,3,4,5, I-Chun Cho1,5
1 Radiation Research Core Laboratory, Chang Gung Memorial Hospital Linkou Branch, Taoyuan, Taiwan.
2 Department of Medical Imaging and Radiological Sciences, Chang Gung University, Taoyuan, Taiwan.
3 Department of Radiation Oncology, Chang Gung Memorial Hospital Linkou Branch, Taoyuan, Taiwan.
4 Department of Radiation Oncology, New Taipei Municipal Tucheng Hospital, New Taipei City, 236, Taiwan
5 Medical Physics Research Center, Institute for Radiological Research, Chang Gung University, Taoyuan, Taiwan.

E-mail: afsgf65445550@gmail.com

Objective: The aim of this study was to develop an irradiation system for small-field (< 2×2 cm²) proton FLASH mouse studies. This technique, characterized by its ability to administer radiation at extremely high dose rates (> 40 Gy/s), presents unique challenges in ensuring dose accuracy, maintaining consistent subject positioning, and achieving homogenous dose distribution within the target area.

Methods: To ensure accurate real-time dose monitoring, a Transmission Ionization Chamber (TIC) was employed, meticulously calibrated with a PTW Pinpoint Ionization Chamber for precision. To precisely target the designated area on the mouse model, the irradiation field was defined using four secondary brass collimators—two circular, with diameters of 1 cm and 2 cm, and two square, with dimensions of 1 cm and 2 cm—positioned subsequent to a lead scatter and a primary brass collimator. The beam's energy consistency and qualitative integrity were verified through Integrator Depth Dose (IDD) measurements utilizing a chamber and water tank configuration, complemented by the application of EBT3 film to evaluate the dose distribution at the mouse immobilization site.

Results: The TIC, crucial for the FLASH application, showed significant stability and accuracy with a dose monitoring uncertainty of less than 3%. The average proton energy was measured at 231.7 MeV, with the R80d depth in water—indicative of the proton dose's penetration—recorded at 315.57 mm.

Conclusions: The irradiation platform developed in this study reliably produces a 1cm x 1cm square proton beam for FLASH irradiation experiments, with dose monitoring effectively managed by a specially designed TIC. This advancement provides a robust foundation for precise and controlled small-field irradiation research, with potential implications for the future of radiobiological and oncological studies.

Keyword
Proton, FLASH, irradiation platform, dosimetry

Speakers: Mr Jyun-Wei Jheng (Radiation Research Core Laboratory, Chang Gung Memorial Hospital Linkou Branch), Dr I-Chun Cho (Chang Gung University)

20240417-The introduction of the proton FLASH experiment beam line in CGMH.pptx

11:20 → 12:20 WG4

11:20 Laser driven Ion Acceleration by Hybrid Scheme Using Dual laser Pulses for NCU 100 TW Laser System

Based on the NCU 100-TW laser system, we use the hybrid scheme, proposed by Isayama et al, using dual laser pulses to drive 53 MeV protons. The dual pulses are identical (810-nm wavelength, 1.5-J energy, 30-fs pulse duration, and 5-micron spot size). The target is composed of a solid-density target and a near-critical density target.
This hybrid scheme combines the three typical schemes: RPA, LWFA, and TNSA. Under this scheme, the proton is first accelerated by RPA and then injected into the near-critical density target. After that, the second pulse generates wakefields in the near-critical density target to provide the secondary acceleration of the proton. In the third phase, the hot electrons are generated in the target's rear so that the sheath field can enhance the proton energy by TNSA.

Speaker: Yao-Li Liu

11:40 Injection and acceleration of positron beam in plasma wakefield

Developing an effective method for the injection and acceleration of positrons in plasma wakefield acceleration has been a persistent issue due to the lack of appropriate wakefield structure. We show that the plasma wakefield driven by a hollow proton beam forms an electron filament along the axis, thus providing the acceleration and focusing fields required by positrons. The evolution of the field can drive the injection of stationary positrons, while the stabilized field can effectively inject relativistic positrons. This work resolves significant challenges related to focusing, injection, and stable long-distance acceleration in positron acceleration, providing an effective scheme for realizing electron-positron collisions through PWFA.

Speaker: Prof. JInqing Yu

12:00 Brightness Enhancement of Laser-driven Coherent Hard X-ray Source

X-rays have extensive applications in biomedical research, physics, and materials science. The Laser Wakefield Accelerator (LWFA) is one of the methods capable of generating X-rays, featuring the advantage of a small footprint. This makes it more convenient for laboratories, hospitals, and other facilities to observe structures such as crystals, drugs, and proteins. The experiment uses the NCU 100TW laser system and LWFA to generate Betatron radiation. The study investigated the intensity variation of Betatron radiation brightness corresponding to electron injection under a tilted shock front. Current results indicate that X-ray photons exhibit varying degrees of enhancement at shock-front tilt angles of 3.8 and 17.1 degrees, with increases of 30% and 140%, respectively.

Speaker: Cheng-Yu Tsai

WG4_Cheng_Yu_Tsai_2024_AFAD_Oral_V3.pptx

12:30 → 13:30 Lunch

13:30 → 15:30 WG1

Chair: JuiChe Huang, NSRRC

13:30 Evaluation of the wakefield effects caused by the orbit fluctuation on the nanometer small beam at ATF

For demonstrating the beam focusing scheme required for linear colliders, the Accelerator Test Facility (ATF) at KEK is designed to focus an electron beam to 37 nm vertical size at the virtual interaction point (IP) utilizing the low emittance beam (vertical emittance: 12~pm.rad) generated in the damping ring. Because of the special focusing beam optics, even small angle changes of beam particles in the beamline can cause significant distortions at IP. The transverse wakefield effects have been observed as beam size growth depending on the beam intensity at ATF. In this report, we describe the wakefield affection on the beam size at IP with pulse-by-pulse beam orbit fluctuations. Simulation and experiments in the final focus beam line of ATF, which have confirmed the effect, are also reported.

Speaker: Yuki Abe (KEK)

20240317_AFAD22024_WG01_ABE.pdf 20240317_AFAD22024_WG01_ABE.pptx

13:50 New beam loss monitor system at the Australian Synchrotron

A new beam loss monitor (BLM) system has been installed and commissioned at the Australian Synchrotron. The new system consists of 28 beam loss detector (BLD) units and 14 signal processing BLM units distributed around the storage ring. Each detector unit consists of a plastic scintillator coupled to a photomultiplier tube. The signal processing units are Libera BLMs from Instrumentation Technology. The new system can detect both integrated slow losses from the stored beam and turn-by-turn losses during injection. This talk will describe the calibration method, the commissioning results, and implementation of a postmortem function to detect unexpected beam loss events.

Speaker: Xuanhao Zhang (Australian Synchrotron)

2024.04.17 AFAD24 - BLM FZhang.pptx

14:10 Commissioning optics for low emittance rings

The strive towards lower emittance in 4th generation light sources often restricts the dynamic aperture and lifetime, creating challenges for injection efficiency and commissioning. Once a circulating beam is established, BPM calibration, BBA and other optics corrections can be applied. However, with a limited DA, it can be difficult to establish a circulating beam at the start of commissioning. To address this problem, we have developed a lattice design that allows for both low emittance optics (for standard user beam operation) and what we have called “commissioning optics” which is a set of lattice parameters that allows for larger dynamic aperture and Touschek Lifetime at the temporary cost of larger horizontal emittance.

Speaker: Tessa Charles (Australian Synchrotron, ANSTO)

AFAD24_comissioning_optics_TKCharles.pptx

14:30 Overview of Korea 4GSR project

A 4th Generation Light Source is being built in Ochang, Korea (Korea-4GSR project). It can produce synchrotron light that is 100 to 1000 times brighter than that of the 3rd generation source like PLS-II in the Pohang Accelerator Laboratory (PAL). The Korea-4GSR is designed to have a circumference of 800 meters to implement a Diffraction-Limited storage ring. This size is three times that of PLS-II, requiring significantly smaller magnet and vacuum chamber apertures for stronger focusing, and the size of the electron beam also reduces by more than tenfold, making the physical/engineering design of the accelerator and the control and stability of the electron/photon beams very challenging. Fully utilizing PAL's experiences gained during the construction and operation of the PLS-II and the PAL-XFEL (a 10-GeV X-ray Free Electron Laser), we have completed the physics design of Korea-4GSR, and the engineering design is now in its final stages, bringing the successful construction of Korea-4GSR closer. Furthermore, through active exchanges with overseas accelerator laboratories, we are trying to strengthen human networks and secure the latest design, testing, and manufacturing techniques.

Speaker: Dr Sung-Ju Park (Pohang Accelerator Laboratory)

AFAD24_Overview of Korea-4GSR Project_Sung-Ju Park.pdf

14:50 Present status of an infrared free-electron laser facility at Chiang Mai University

A project to develop a linac-based MIR/THz free-electron laser (FEL) light source and experimental stations for spectroscopic and ultrafast interaction applications is underway at Chiang Mai University in Thailand. The accelerator system serving as the electron beam injector is an existing system, albeit with modifications to accommodate two newly developed beamlines for MIR/THz FEL. Engineering design and construction of new components in magnetic bunch compressors and FEL beamlines, have been conducted based on physics design and beam dynamic simulations. Currently, nearly all components have been installed in the accelerator hall, and the commissioning of the system is in progress. This contribution provides an overview of the project, a report and a discussion of the design and beam dynamic simulations for both the oscillator MIR FEL and the super-radiant THz FEL as well as the development of components. Furthermore, the current status of the facility will also be presented.

Speaker: Dr Sakhorn Rimjaem (Chiang Mai University)

AFAD2024_Rimjaem_Present status of an IR-FEL facility at CMU.pdf AFAD2024_Rimjaem_Present status of an IR-FEL facility at CMU.pptx

13:30 → 15:30 WG3

Chair: Anatoly Rozenfeld, University of Wollongong

13:30 The application for accelerator based radiation therapy Overview of the development in Taiwan

According to the data and analysis of the Cancer Registry Annual Report in Taiwan, it can be seen from the trends in the past 10 years in 2020 that the growth in the incidence of major cancers is approximately 3.32% in the number of patients per year. The first new case of aggressive cancer finding in Taiwan is 116,131 and there are 30,796 patients received radiation therapy during the first course of treatment in 2018. It means around 28% of new case of aggressive cancer finding will receive radiotherapy.
The trends in emerging accelerator based radiation therapy in Taiwan has ranged from 3D CRT in 1996 to IMRT in 2001 and even the vigorous development of particle therapy since 2015. Not only the development of particle therapy, but the application of images guidance during treatment will become increasingly widespread and in-depth, creating a need for clinical application of offline and online adaptive radiotherapy.
There are four particle therapy center in operation including three proton center and one heavy ion center in Taiwan. We are expect having eight particle center and seventeen treatment rooms in operation by the end of 2025.

Speaker: YUNG-FA LU (Taichung Veterans General Hospital)

The application for accelerator based radiation therapy Overview of the development in Taiwan - V4.pptx

13:50 Design study of a high-current Q/A=1/2 K100 compact cyclotron for multi-disciplinary utilization

Magnetic design and beam optics studies have been carried out for a K100 cyclotron, which can accelerate Q/A=1/2 ions to the maximum energy of 25 MeV/u. Since proton acceleration using H2+ instead of H+ or H- can double the maximum beam current primarily limited by space charge effects at the injection energy of compact cyclotron, we expect a maximum current of over 2 mA can be achieved by existent cyclotron technology. In addition, D+, He2+ can be accelerated with slight adjustments of rf frequency so as to produce fast neutrons and medical isotopes such as 211At for advanced cancer therapy. Also, we consider employing a charge stripping method to extract H2+ at an energy of around 10 MeV to produce low-energy neutrons more optimally. I will present major features of the cyclotron design.

Speaker: Jong-Won Kim (Institute for Basic Science (IBS))

AFAD 2024-Jongwon Kim-4-12-2024.pdf

14:10 DIRAMS C-band LINACs for preclinical FLASH electron beam irradiation

The 6-MeV and 9-MeV electron linear accelerators (LINACs) were designed and constructed in 2015 and in 2018 at the Dongnam Institute of Radiological & Medical Sciences (DIRAMS), Busan, Korea. Their C-band accelerating columns were chosen as a bi-periodic on-axis coupled structure and operated in the π/2 standing-wave mode. They are used for preclinical irradiators for in vitro studies of cells and small animals, and the development & test of LINAC components. Preclinical studies have shown that irradiation with ultra-high dose-rate beam known as FLASH kills cancer cells with minimal damage to normal cells. The DIRAMS LINACs provide the conventional dose rate beam (<0.1 Gy/s) and also the ultra-high dose-rate beam (> 40 Gy/s) by the precise control of the pulse modulator combined with a single-board computer. For the real-time monitoring of FLASH beams, the delivered dose was estimated by the measured charge by the transmission-type ionization-chamber. In this talk, we present the status of DIRAMS LINACs and also the preclinical results.

Speaker: Dr Heuijin Lim (Dongnam Institute of Radiological & Medical Sciences)

20240417_AFAD_DIRAMS_HL.pdf

14:30 Investigation of High-power 4K Nb3Sn Superconducting RF Electron Linac for Production of Medical Radioisotopes

Various types of radioisotopes (RIs) are used in the field of nuclear medicine for diagnosis, such as PET and SPECT. In recent years, RIs are applied to therapy of cancer and the Ac-225 has been confirmed to be effective in the treatment of advanced cancer. One of the promising RI production methods for medical application is the use of high-intensity beam in accelerators. In the case of an electron accelerator, a photonuclear reaction is used in the RI production process. We have started research and development of a 4K niobium-tin (Nb3Sn) superconducting RF (SRF) electron accelerator system for RI production, which can be operated with a compact conduction cooling system and does not require a large-scale cooling system. As a first step, we plan to develop a single-cell Nb3Sn superconducting cavity and a cryomodule to cool it, and to demonstrate its performance by beam acceleration experiments. In this presentation, we report the basic design of the SRF electron linac and R&D schedule of the 35 MeV SRF linac for the RI production.

Speaker: Shigeru Kashiwagi (ELPH, Tohoku University)

AFAD2024(WG3)forTalk_kashiwagi.pdf AFAD2024(WG3)forTalk_kashiwagi.pptx

14:50 Flexible organic semiconductors and amorphous silicon detectors for synchrotron microbeam radiation therapy dosimetry

Introduction: Detectors that can provide accurate dosimetry for microbeam radiation therapy (MRT) must satisfy a number of challenging criteria including having intrinsic radiation hardness, a high dynamic range, energy and dose rate independence, and a spatial resolution able to resolve x-ray microbeam spacings on the order of hundreds of microns.
At the Centre for Medical Radiation Physics, several solutions using electronics grade silicon devices have been explored in the last decade to measure dose in MRT. The limitations of silicon-based devices includes a small dose rate dependence and energy dependence, but most significantly, a large radiation beam distortion caused by the silicon substrate. Even in thinned devices, this distortion has dimensions comparable with the primary radiation field, resulting in a measurable distortion of the dose profiles and in the under-estimation of the peak-to-valley dose ratios. In recent years, detector architectures based on amorphous materials as sensitive volumes have been explored due to their possibility to be deposited in the form of films on flexible substrates such as Polyimide (Kapton). Two examples of these technologies are hydrogenated amorphous silicon (a-Si:H) planar diodes and solution processable organic semiconductor bulk heterojunctions (OSC). The dosimetric performance of these detectors are reported for both broad beam and microbeam modalities, and over a range of beam filtrations with experiments performed at the Australian Synchrotron in Melbourne.
Results: The synchrotron x-rays were spatially fractionated into an array of 50 microbeams with a Full-Width-Half-Max of 50 µm and a peak-to-peak distance of 400 µm to explore the potential to use amorphous thin film detectors for MRT dosimetry. The sensitivity and energy dependence of the aSi:H detectors fabricated with a combination of N, P and intrinsic a-Si:H showed a high sensitivity and an energy dependence matching closely to the attenuation coefficient ratio of Silicon against Water, despite the substrate being only 0.8 µm thick. The radiation damage of a-Si:H detectors out to 40 kGy is limited and stabilises at approximately -17% of the response in pristine conditions. Percentage depth dose profiles from the a-Si:H detector matched those from a PTW microDiamond detector to within ± 5 % for all beam filtrations, except in 3T Al-Al due to the energy dependence of the material. The microbeam field profile was reconstructed with a high spatial resolution and returned microbeam widths and peak-to-peak distances of (51 ± 1) µm and (405 ± 5) µm, respectively. The peak-to-valley dose ratio was measured as a function of depth and agrees within error to the values obtained with the PTW microDiamond. Regarding organic (OSC) detectors, the highest sensitivity of the flexible 250 nm thick film under the broad beam was determined to be (1958 ± 31) pC Gy-1cm-2 under 0 V bias. The organic x-ray sensor measured a FWHM of (51.6 ± 1.9) µm averaged across 3 beam filter conditions. The radiation tolerance of the organic detector was explored by exposing the organic detector to continuous irradiation at a 4.5 kGy/s dose-rate. The direct response decreased by 35% after a total irradiation dose of 45 kGy. The dosimetric performance of the OSC sensor with Kapton packaging was compared to an identical sample with PET packaging. Broad beam measurements of the PET sample demonstrated an additional signal from the PET fluorescence incident on the OSC active layer generating an opposing negative charge that significantly reduced the sensitivity and reliability of the output for sensitivity measurements.
Conclusions: The a-Si:H detectors proved to be comparable to commercially available dosimeters employed for quality assurance in MRT. OSCs devices show a high radiation hardness, no energy dependence, and extreme spatial resolution. The results demonstrate the need for additional considerations that must be given to the device packaging when designing flexible and low-cost radiation detectors for real-world applications. This work proves that amorphous materials are interesting alternatives for dosimetry in synchrotron-based radiotherapy modalities.

Speaker: Prof. Marco Petasecca (University of Wollongong - Centre for Medical Radiation Physics)

Flexible organic semiconductors and amorphous silicon detectors_PETASECCA.pptx

15:10 MOSkin dosimetry for very high-energy electron FLASH at Australian Synchrotron PEER

FLASH radiotherapy (RT) is an emerging cancer treatment modality that utilises much higher dose rates than conventional RT. Delivering radiation with ultra-high dose rates (UHDR) has been shown to spare healthy tissue while providing an equal or greater dose to the tumour. Current research suggests the use of very high-energy electrons can provide further benefits, such as treatment of deep seated tumours. Linacs have been used to deliver ultra-high dose rate electrons, with current dosimetry utilising radiochromic film. However, film does not provide the real-time results required in a clinical setting. The MOSkin detector, designed at the Centre For Medical Radiation Physics at University of Wollongong is used in conventional radiotherapy and considered dose-rate independent over a limited range. This study aims to show that dose-rate independence continues to exist when exposed to a UHDR, very high energy electron (VHEE) beam.

The Australian Synchrotron uses a linac to inject 100 MeV electrons, capable of delivering pulses with expected dose rates of $10^7$ Gy/s. The linac lacks beam scanning or positioning equipment so an array of five detectors was designed, built and manually positioned with the assistance of a portable laser. An x-ray intensifier screen was positioned behind the array and imaged with a camera, to collect spatial data and relative beam intensity between pulses. 13 beam currents were used to deliver 300 pC pulses from 20 ns to 400 ns in length.

The detector with the highest response was assumed to be closest to the beam centre and an average response for each beam current was calculated. Dose rates for each pulse were estimated using a standard MOSkin calibration factor and range from approximately $7x10^5$ – $2.5x10^7$ Gy/s. A steep drop off in response was observed at beam currents below 2 mA. Beam profiles were created using the camera data, with a Moffat distribution fitted to determine relative intensity between pulses at the detector's estimated location. The amplitude was extracted from the distributions and normalised to 1, which enabled plotting against normalised MOSkin data to evaluate detector response against the charge delivered. The MOSkin response is consistent with the x-ray intensifier screen and indicates pulses are being delivered to the experimental stage at lower beam current than that measured by the linac diagnostics.

While the imaging equipment cannot provide an estimate of dose, it explains the variance in detector behaviour between pulses, especially at lower dose rates. While uncertainty is large due to manual positioning, the experiment has shown that further investigation is justified as the MOSkin appears suitable for dosimetry in UHDR VHEE FLASH environments. Future experiments will be conducted to gain better spatial information as well as an independent measurement of dose.

Speaker: James Cayley (Centre for Medical Radiation Physics - University of Wollongong)

VHEE_MOSkin_PEER_afad24.pptx

13:30 → 15:30 WG4

13:30 Stilling chamber assisted Stable Electron Beam Generation in LWFA

The laser wake-field acceleration (LWFA) provides energetic electron beams with higher acceleration gradient. The typical strength of the electrostatic field reaches GV/cm. Significant developments have been achieved in the past decades and various mechanisms have been proposed for beam quality improving. LWFA is expected to deliver high quality electron beams for potential applications. However, it requires high stability and reproducibility of the ejected beam which are still far away from the current laser driven plasma accelerator.
Supersonic nozzles are commonly used in LWFA to provide spatially well-defined gas targets with a plateau density profile and sharp gas-vacuum boundaries. To maintain the reproducibility of the accelerated electron beam, a stable gas target in the vacuum chamber with precise density distribution profile is necessary. It guarantees that the laser-plasma interacts in a proper density region　and the relative laser focal point doesn't shift too much from shot to shot. In this work, we focus on the instability originated from the gas jet due to the nonlinear fluid dynamics in the supersonic nozzle. The role of the stilling chamber in a modified Converging-Diverging nozzle is investigated. According to the fluid dynamics simulations, the chamber dissipates the turbulence and stabilizes the gas jets. Via both the numerical simulations and the Mach-Zehnder interferometric measurements, the instability originated from the nonlinear turbulence and the mechanism to suppress the instability are studied.

References
[1] Z. Lei, et al., Rev. Sci. Instrum. 95, 015111 (2024).
[2] Z. Lei, et al., High Power Laser Sci. Eng. 11, e91 (2023).

Speaker: Dr YANJUN GU (SANKEN, Osaka University)

13:50 LCODE 3D: A New Open-Source Tool for 3D PWFA simulations

We present LCODE 3D, a new tool that allows for simulations of plasma wakefield acceleration in three-dimensional geometry using a quasi-static approximation. Based on the principles of the time-tested LCODE 2D code, LCODE 3D offers the flexibility of switching between different geometries, allowing for efficient work when three-dimensional effects have minimal impact. Furthermore, LCODE 3D is an open-source tool written in Python, providing readability and ease of use. By using JIT compilation and numpy libraries, the computational time for simulation is comparable to the older version written in C. LCODE 3D supports parallel calculations using CUDA or MPI, enabling efficient simulations for large-scale problems.

Speaker: Nikita Okhotnikov (Novosibirsk State University, Budker Institute of Nuclear Physics)

Okhotnikov_AFAD.pptx

14:10 Numerical Study of Polarized X-ray Generation by Tilted Shock-Front Injection

Recently, there has been considerable attention on high-polarization table-top hard X-ray sources, which facilitate easy deployment in clinics and university laboratories, providing convenient access to results regarding material microstructures or properties. Betatron radiation, one of the X-ray sources that has femtosecond range duration, μm spot size, and compact equipment, is considered an alternative to large synchrotron facilities. The experimental condition based on the NCU 100TW laser to generate high brightness and polarized X-ray is examined numerically in this study. The electron injection mechanism under tilt shock front was studied in transverse and longitudinal wavebreaking, as well as the polarization behavior of X-ray photons. It was found that under the transverse wavebreaking injection mode, the degree of polarization increased from 20% to 68%. This suggests that in experiments, we can easily increase the polarization of X-ray sources by controlling the angle of the shock front.

Speaker: SUNG-WEI HUANG (National Central University)

Numerical Study of Polarized X-ray Generation by Tilted Shock Front Injection.pptx

14:30 Quasistatic simulations of long-distance laser wakefield acceleration

Quasistatic approximation (QSA) offers opportunities for computationally efficient modeling of laser pulse propagation over long distances. When simulating the channeling of a powerful laser pulse over tens of meters (studied in the context of XCELS project), the QSA gives a speedup of six orders of magnitude compared to the particle-in-cell method. This estimate takes into account the need to resolve the laser wavelength for correct modeling of a strongly depleted pulse. Moreover, QSA allows to speed up the parametric optimization of the wakefield acceleration by dividing it into two steps: first we find the best regime of laser pulse propagation, and then we optimize the witness parameters by simulating the wave only in the vicinity of the witness. The two-step optimization also minimizes the witness emittance growth due to numerical noise of the plasma solver.

Speaker: Daniil Kutergin (Budker INP)

KuterginQSA.pptx

14:50 Single-shot spatial-temporal electro-optic diagnostic of laser wakefield accelerated electron bunches

By introducing the electron-optic Sampling technique in to the research of laser Wakefield acceleration, we have conducted single-shot spatial-temporal detection on the electron bunches.In our recent experiments, we have measured the electron timing fluctuation at a position outside the plasma. By simultaneously performing optical transition radiation imaging and EO spatial decoding, the absolute 3D density profile of the an electron bunch has been reconstructed. For data analysis, detailed numerical studies were carried out. This study could have broad impact in researches of high power, accelerators and THz optics.

Speaker: Kai Huang (National Institutes for Quantum Science and Technology (QST))

AFAD2024_Kai3DEngv1.pptx

15:10 Creating an asymmetric density profile in a sub-mm nitrogen gas jet to enhance the performance of few-TW laser wakefield acceleration

Fabricating a thin, dense gas target capable of providing a plasma electron density of > 10^{19} cm^{-3} enables the operation of laser wakefield acceleration (LWFA) with few-TW or even sub-TW pulses, as a strong laser intensity can be achieved for the self-focused and self-modulated pump pulse to drive plasma waves for electron acceleration. The high plasma density used here, however, results in a short dephasing length of < 100 µm, which substantially limits the energy gains for accelerated electrons and degrades the quality of the output beams. Based on the results of LWFA acquired with a 1-TW laser pulse and a default nitrogen gas jet characterized by a length of 670 µm and a peak electron density of 4.5 x 10^{19} cm^{-3}, we investigate the feasibility of improving beam properties by shaping the density profile of a gas jet with a shortened density-down ramp region to inhibit electron dephasing therein. Hence, by placing a blade above the nozzle to impede part of the gas flow, an asymmetric density profile featuring a reduced density-down ramp length of 150 µm and a lowered peak electron density of 3.9 x 10^{19} cm^{-3}was created, accordingly. Results showed that using the asymmetric/shaped nitrogen gas jet helped to reduce the horizontal pointing fluctuation to 5.3 mrad when compared to 19.2 mrad obtained with the default jet. The shaped gas jet also contributed to a higher bunch charge of 16.3 pC than that of 5.8 pC with the default jet, which can be attributed to the mitigated dephasing of accelerated electrons and the moderated depletion of pump pulse as shown by the related particle-in-cell simulation.

Speaker: Mr Dang Khoa Tran (National Tsing Hua University, Taiwan)

15:30 → 16:00 Coffee Break

16:00 → 16:40 WG1

Chair: JuiChe Huang, NSRRC

16:00 Measurement of the yields of photon stimulated desorption and photoelectrons at a PSD-beamline

Synchrotron radiation induced high yields of gas-desorption and photoelectrons from the vacuum beam ducts of large accelerators results in huge impacts of shortening the beam lifetime and beam instabilities from the trapped ions or electron cloud. Inspection of surface cleanness and coated materials on top surface layers of beam ducts by directly measuring the photon stimulated desorption (PSD) and photoelectron yield (PEY) at a beamline of synchrotron light source provides a quick and sensitive analysis of surface qualities of cleanness. A PSD-beamline BL19B of 1.5 GeV Taiwan Light Source (TLS) features a prompt measurement of PSD-yield and PEY for various vacuum tubes, e.g. titanium, stainless steel, copper, aluminum alloys, and the NEG-coated chambers, will be described in this presentation.

Speaker: Mr Gao-Yu Hsiung (NSRRC)

AFAD2024-WG1_Hsiung.pdf AFAD2024-WG1_Hsiung.ppsx

16:20 Resonant Cherenkov diffraction radiation for the beam diagnostics

We have developed a periodic Cherenkov radiator to obtain narrow band Cherenkov radiation. Since the radiation spectrum of Cherenkov diffraction radiation from the radiator contains strong higher order harmonics, the bunch form factor of the electron beam is expected to be deduced precisely, so that the very short bunch less than 10 fs (such as the laser wakefield accelerated beam) is able to be measured. We have done some test experiments with 100 fs bunches at t-ACTS of Tohoku University. Some theoretical consideration and experiments data together with discussions will be presented.

Speaker: Prof. Hiroyuki Hama (Tohoku University)

AFAD2024-HAMA.pptx

16:00 → 17:40 WG2

Chair: Chang-Seong Moon, KNU

16:00 Development of the detectors and conducting experiments with Tunka-Grande and TAIGA-Muon scintillation detectors arrays

Tunka-Grande and TAIGA-Muon are scintillation detector arrays that are part of the TAIGA gamma observatory located near Lake Baikal. TAIGA is a hybrid complex of different systems located on an area of 1 km2 and detecting simultaneously secondary charged particles and Cherenkov light produced by extensive air showers (EAS). The experimental scientific program covers gamma-ray astronomy, cosmic ray physics and astroparticle physics.
Tunka-Grande scintillation array was put into service at the end of 2015. It consists of 19 stations each equipped with 12 surface and 8 underground detectors with the area 0.64 m^2. The energy range of Tunka-Grande array is 10^16–10^18 eV. The latest experimental results on the search for diffuse gamma radiation will be presented.
To expand the energy range of the experiment to 10^15 eV, it was decided to supplement the existing detector system with a new TAIGA-muon installation. For this purpose, the new scintillation detectors of large area (0.96 m^2) were developed. These detectors use wavelength shifting light guides for the collection of scintillation light on the PMT. The original design helped to minimize the thickness of the scintillator in the counter and allowed to use small PMTs in the detector. All these minimize the cost of the counter. At the moment, 5 new TAIGA-Muon stations have been installed. One station comprises 20 underground and 4 surface detectors. The 4 remaining consist of only 8 surface detectors. This summer all of them will be equipped with underground detectors. The scientific program of the upgraded scintillation arrays includes the search for diffuse gamma radiation in the extended energy region, study of the mass composition of cosmic rays and search of multi-messenger events in coincidence with other astroparticle experiments.

Speaker: Dr E.A. Kravchenko (Novosibirsk State University/ Budker Institute of Nuclear Physics)

KravchenkoAFAD2024.pdf

16:20 Laser polarimeter for measuring the beam energy of the VEPP-4M accelerator using the resonant depolarization method

The KEDR detector at the VEPP-4M accelerator complex plans to measure the mass
of the Y(1S) meson with an accuracy better than 50 keV. This experiment
requires precision measurement of the beam energy. The most accurate method of
measuring beam energy is the resonance depolarization method. The method is
based on the connection of the particle energy with the spin precession
frequency, which is determined by the destruction of the beam polarization in
the presence of an alternating electromagnetic field. The polarization of the
beam is measured by the asymmetry of the Compton backscattering of
circularly polarized photons on transversely polarized electrons. The report is
devoted to the description of the "Laser Polarimeter" facility and the
features of beam energy measurement. An Nd:YLF laser with a wavelength of 527
nm and an average power of 2 watts is used as a photon source. The
backscattered gamma quanta are detected using a two-coordinate detector based
on triple GEM. The laser polarimeter allows measuring the energy of the VEPP-4M beam
with an accuracy of about 15 keV in 30 minutes directly during the data collecting by the KEDR detector.

Speaker: Dr Ivan Nikolaev (Budker Institute of Nuclear Physics)

report.pdf

16:40 Construction and commissioning of a new T2K near detector SuperFGD

The T2K experiment is a long baseline neutrino oscillation experiment aiming to discover CP violation in neutrino mixing. A new detector, SuperFGD, has been installed in the near detector since October 2023 to reduce systematic errors in the neutrino oscillation analysis. It consists of about 2 million 1 cm scintillator cubes, about 56,000 wavelength shifting fibers penetrating them from three directions, and an equal number of photodetector MPPCs. The SuperFGD recorded its first neutrino beam data in December 2023. We report about the assembly and commissioning of the unique detector.

Speaker: Hikaru Tanigawa (KEK)

AFAD2024_SFGD_tanigawa.pptx

17:00 Development of LGAD Sensors at IHEP

The Low Gain Avalanche Diode (LGAD) is a novel silicon sensor known for its excellent timing resolution. The AC-Coupled LGAD (AC-LGAD) is a new type 4D detector developed based on LGAD technology, capable of accurately measuring the time and position information of particles. This presentation will showcase the development status of LGAD and AC-LGAD sensors designed by the Institute of High Energy Physics (IHEP). Following irradiation fluence of 2.5 × 1015 neq/cm2, the time resolution of IHEP LGAD sensors is superior to 35 ps, with collected charges exceeding 10 fC. The IHEP LGAD has been selected as the sensor for the ATLAS High Granularity Timing Detector (HGTD) project. The position resolution of IHEP AC-LGAD can achieve 10 μm, with a time resolution of 38 ps, making it suitable for the development of time-track detectors in future collider experiments such as the Circular Electron Positron Collider (CEPC) and the Future Circular Collider (FCC).

Speaker: Mengzhao Li (Institute of High Energy Physics, Chinese Academy of Sciences)

AFAD-IHEPLGAD-v2.pdf

17:20 Detector development of the Beam Expansion Application at CSNS

The China Spallation Neutron Source (CSNS) was completed in March 2018, and it is the first spallation neutron source in China. The CSNS project plans to construct four beamlines for beam expansion applications, including a back-streaming white neutron beamline, a medium-energy proton beamline, a high-energy proton beamline, and a surface muon beamline. Around these four beamlines, we have developed a series of detectors for use in various experiments, including beam monitoring, beam profile measurement, charged particle detection, etc. All these detectors will be briefly presented in this report, with a particular focus on the TPC used for neutron-induced secondary cross-section measurement and the B-MCP detector for neutron resonance photography.

Speaker: Dr You Lyu

YouLyu-AFAD2024-v1.pptx

16:00 → 17:40 WG3

Chair: Anatoly Rozenfeld, University of Wollongong

16:00 High-precision ion irradiation of materials and devices for prototyping and applications to microelectronics, photovoltaics, and space

This work presents recent achievements in development and applications of ANSTO’s ANTARES [1] and SIRIUS [2] microprobe systems for the high-precision irradiation of materials and devices for prototyping and applications to microelectronics, photovoltaics and space. The ANSTO systems can be optimized to deliver a required combination of linear energy transfer, ion range, scanning size and speed and uniform ion flux or dose rate of proton (1-10 MeV/u) and medium - heavy ion (1-3 MeV/u) microbeams produced by the 10 MV tandem Van de Graaff accelerator and focusing ion microprobe (EM/q2=120), and thus meet custom demand for testing. The ANSTO testing capability offers 1) the 3D precision targeting of ions in user preselected region of interest in a device, 2) the rapid scanning microbeam irradiation with customized sweep time (pixel dwell time and pixel size), the slower, but larger in dimension, sample scanning with adjustable micromanipulator stage velocity or the hybrid-scanning (combining benefits of two) [3], 3) the optimized ion microbeam parameters (LET, energy(E), range(R), flux, and particle rate) and 4) irradiation in vacuum or in ambient [4]. For testing on the micrometer and microsecond scale we currently provide focused microbeams of: 1) protons (up to E=12MeV, LET(Si)≈ 0.03MeVcm2/mg, R(Si)≈800 micron), carbon ions (up to E=36 MeV, LET≈3 MeVcm2/mg, R≈40 micron), silicon ions (42 MeV, 14 MeVcm2/mg, 15 micron), chlorine (54 MeV, 17 MeVcm2/mg, 16 micron), iron (55 MeV, 28 MeVcm2/mg, 13 micron) and nickel ions (62 MeV, 28 MeVcm2/mg, 13 micron), but other ions with different E, LET and R values can also be arranged. As examples, we show case studies of 1) the Ion Beam Induced Charge – IBIC imaging of SOI and CVD diamond microdosimeters [5], 2) the PEEK material radiation hardness [6], 3) the effectiveness of prototyped magnetic shielding against ions in LEO for small cube satellites [7], 4) the radiation hardness and thermal recovery of proton irradiated Perovskite solar cells [8], and 5) the SEU and TID evaluation of SRAM chips [4].

[1] R. Siegele et al, Nucl. Instr. Meth. in Phys. Res. B 158, 31 (1999).
[2] Z. Pastuovic et al, Nucl. Instr. Meth. in Phys. Res. B 404, 1 (2017).
[3] S. Peracchi et al., Proc. 22nd Eur. Conf. on Radiat. Effects Compon. Syst. (RADECS), Venice, Italy, 2022.
[4] S. Peracchi et al., IEEE Trans Nucl. Sci. (In Press).
[5] V. Pan et al., IEEE Trans. Nucl. Sci. 70(4), 568 (2023).
[6] K. Rasheed et al., Polymer Testing 132, 108354 (2024).
[7] Under review.
[8] S. Tang et al., Adv. Energy Materials 13, 2300506 (2023).

Speaker: Dr Zeljko Pastuovic (CAS-ANSTO)

16:20 Design and Implementation of accelerator control system for D-BNCT

In recent years, Boron Neutron Capture Therapy (BNCT) has seen vigorous development, and the BNCT facility (D-BNCT) at the People's Hospital of Dongguan City, Guangdong Province, is also under construction. This report introduces the design and implementation of the accelerator control system for D-BNCT, which utilizes the Experimental Physics and Industrial Control System (EPICS) as the software platform. has achieved remote control and status monitoring of the accelerator equipment, as well as interfaces with the treatment control system. The system has been installed and is currently undergoing joint commissioning with the treatment control system.

Speaker: Mr Xuan Wu (IHEP, CAS)

Design and Implementation of accelerator control system for D-BNCT.pptx

16:40 Speeding up proton therapy: progress towards beam delivery using Fixed Field Accelerator technology”

Access to proton therapy is limited by both facility cost and existing technological limitations. The beam delivery system (BDS) has been identified as a bottleneck, particularly for new and emerging methodologies such as FLASH, Arc, and multi-ion therapies. This talk will discuss a new collaborative project between Harvard/MGH, University of Melbourne and Pyramid technologies for a compact, fast proton therapy system. We will focus on the 'TURBO' ‘Technology for Ultra Rapid Beam Operation’ project: a novel proof of principle BDS in development in Melbourne, utilising novel Fixed Field Alternating Gradient optics. This system will increase the BDS energy acceptance to allow multiple beam energies to be transported, reducing the dead time between energy layers and enabling rapid beam delivery across the whole tumour depth. We discuss the potential and clinical benefits of TURBO as a fixed-beamline BDS with fast energy switching for CPT.

Speaker: Suzie Sheehy (University of Melbourne)

AFAD24-Sheehy-slides.pptx

17:00 Linac-based Intense Coherent THz Sources Developed for User Applications

Linac-based coherent THz radiation sources are being developed with the NSRRC high brightness photoinjector which has been installed in the Accelerator Test Area (ATA). The injector is equipped with a laser-driven photocathode rf gun and a 5.2-m long S-band traveling-wave linac for beam acceleration. A 25 MeV beam of bunch length as short as 240 fs has been produced from this injector by the so-called velocity bunching technique. Narrow-band superradiant THz radiation of pulse energy as high as 20 μJ and tunable central frequency from 0.6 to 1.4 THz can be generated by injecting such ultrashort beam into a U100 planar undulator. The intense THz light source will be a useful tool for applications such as material science and biomedical imaging. A THz user beamline is under designed and construction and expected to open for users by the end of 2025.

Speaker: Dr Ming-Chang Chou (NSRRC)

2024AFAD_WG3_THz.pptx

17:20 Industrial Applications at NSRRC –Taiwan’s Experiences

As echoing to the national demanding for industry development, the Industry Application Division (IAD) in the National Synchrotron Radiation Research Center (NSRRC) in Taiwan was established and launching its mission since 2008. Serving as the acting window in NSRRC, the IAD bridges the synchrotron-radiation (SR) analytical tools mainly to key domestic industries with practical and critical resolutions to boosting added-up values for genuine industrial concerns.

After years of promotion, the IAD of NSRRC has cultivated analysis capacities for several targeting industrial needs with fruitful results, including the high-tech semiconductors, green energy and batteries, advanced polymers and carbon fibers, steels and iron metallurgy, pharmaceuticals, and micro-devices as well, which will be briefed in the presentation.

Speaker: Dr Bor-Yuan Shew (NSRRC)

AFAD 2024-industry-handout 2.pdf

16:40 → 17:40 WG6

Chair: JuiChe Huang, NSRRC

16:40 Grid Deployment in the KEK Central Computing System (KEKCC)

The KEK Central Computing System (KEKCC) is a computer service and facility that provides large-scale computer resources, including Grid and Cloud computing systems and essential IT services, such as e-mail and web services.

Following the procurement policy, we have replaced the entire KEKCC with a new one once every four or five years. Since 2024 is the last year of the current KEKCC contract, we would like to review the operational and development achievements regarding the Grid system introduced in the KEKCC. Also, we will share the planned schedule, resource scales, etc, for the next KEKCC, which will be in production in September 2024.

Speaker: Dr Go Iwai (KEK)

kek-iwai-WG6-rev5.pptx

17:00 KREONET/KREONet2 and Global Research Network for Accelerators and Detectors in Asia

To process experimental data from high-energy physics experiments, large amounts of data should be shared world-widely. Data movement is essential for global collaborative research. We introduce KREONET/KREONet2, national science and research network in South Korea that enables to transfer big data for high-energy physics community in Asia. Also we gives a talk about collaborative efforts to build global research network like APONET, AER, EARBN and discuss how to build community network for Asian accelerators and detectors.

Speaker: Chanjin Park (KISTI)

AFAD 2024(KREONET_KREONet2)v2.pdf

17:20 Local Engagement of Network & Grid Computing in Taiwan

We’d like to talk about the status and prospect on the research network and grid computing for high energy physics studies in Taiwan.

Speaker: Dr YUAN CHAO (Department of physics, National Taiean University)

ychao_20240417.pdf

18:00 → 20:00 Reception

Thursday, 18 April

08:00 → 09:00 Registration

09:00 → 10:20 Plenary talk

Chair: Hsin-Pai Hsueh, NSRRC

09:00 Present and Future of Pohang Accelerator Laboratory

PAL, established in 1988 with full support from the Pohang University of Science and Technology, has acted as a powerhouse to support basic science and technology in Korea and has secured a competitive edge frontier after making ceaseless efforts. PAL is now operating PLS-II and PAL-XFEL.

PLS-II is the 3-rd generation synchrotron with 3-GeV beam energy and 5.8 nm emittance. Thirty-six beamlines are operational for user-service operation. PAL-XFEL is a hard X-ray free-electron laser facility based on 10-GeV normal conducting linac. One hard X-ray and a soft X-ray FEL are operational for user-service operation.

The PAL-XFEL has demonstrated excellent timing stability and unprecedented peak brightness since its start of user service operation in June 2017, outperforming other XFEL facilities worldwide. The 18-fs timing stability in the XFEL allows excellent pump-probe time-resolved experiments with low-timing jitter. A self-seeding scheme enables us to produce a higher peak brightness of the XFEL with a narrow bandwidth: the peak brightness of 3.2 x 1035 photons/(s·mm2·mrad2·0.1%BW) at 9.7 keV and the bandwidth of 0.19 eV, the best to date. To provide more beamtime to users, we started the 2nd hard X-ray FEL line project in 2024 and will finish it by 2027.

For our current or potential scientific users, we will continue to strengthen our capacity, scientific programs, and industry engagement and maximize our impact as a major contributor to the cutting-edge future of science in Korea.

Speaker: Heung-Sik Kang (Pohang Accelerator Laboratory)

PAL_status_AFAD_2024_hskang.pdf

09:40 Ultra-high-brightness Photon Sources driven by Dielectric Laser Accelerator

The acceleration gradient of a solid-state accelerator is limited by the damage of the acceleration field on an accelerator structure. A dielectric, which is widely used for high-power lasers, is therefore the choice of material for an accelerator operating at the optical frequencies. Owing to the much shorter drive wavelength, a dielectric laser accelerator (DLA) built upon a photonic chip could produce nano-electron bunches useful for studying attosecond science or generating electron superradiance in the EUV and soft x-ray spectrum. We show in this presentation that, in the low-current limit, a DLA-driven photonic chip can generate laser-like radiation from a single electron and a train of single electrons; where, with ~fC bunch charge, DLA-driven coherent undulator radiation is the brightest photon source on Earth when the brilliance of radiation per beam power is considered.

Speaker: Yen-Chieh Huang

Yen-Chieh Huang_AFAD.pdf

10:20 → 11:10 Coffee Break

11:20 → 12:20 WG2

Chair: Chang-Seong Moon, KNU

11:20 On recent progress and perspectives in development of aerogel based Cherenkov detectors for future colliding beam experiments

Now there are several colliding beam experiments proposed for realisation in a future all around the world. Among them are hadron colliding beam experiment SPD at NICA (JINR, Dubna, Russia)[1], electron-positron colliding beam experiments SCTF (Sarov, Russia)[2], STCF (Hefei, China), CEPC (China)[3], and electron-ion colliding experiment EicC (Huizhou, Guangdong, China) [4]. The construction of an universal detectors for every one of these experiments are presumed. The particle identification system is the natural part of each these universal detectors. The aerogel based Cherenkov detectors are able to provide excellent particle separation in wide momentum range. For some of these experiments like SPD or EicC only pi/K-separation up to high momentum range is required for other such like SCTF the mu/pi-separation up to 1.5 GeV/c. To satisfy these requirements to PID system several RICH detector concepts based on aerogel Cherenkov radiators are under consideration. The recent progress in aerogel Cherenkov radiators production in Novosibirsk is presented. Evaluations of expected performances for several RICH concepts like FARICH or mRICH based on Novosibirsk aerogel is given. For the first time direct comparison of aerogels produced in Novosibirsk and in China performed with help of optical measurements and beam tests as well. The new concept of RICH detector based on aerogel fibres produced in SINANO is proposed. Some peculiarities of this concept and results obtained with help of MC simulation are discussed too.

[1] http://spd.jinr.ru
[2] https://sct.inp.nsk.su
[3] http://cepc.ihep.ac.cn
[4] https://indico.pnp.ustc.edu.cn/event/1191/overview

Speaker: Alexander Barnyakov (Budker Institute of Nuclear Physics)

afad24_barnyakov.pdf

11:40 Precision Timing at High-Luminosity LHC with the CMS MIP Timing Detector

The MIP Timing Detector (MTD) is a new sub-detector planned for the Compact Muon Solenoid (CMS) experiment at CERN, aimed at maintaining the excellent particle identification and reconstruction efficiency of the CMS detector during the High-Luminosity LHC (HL-LHC) era. The MTD will provide new and unique capabilities to CMS by measuring the time-of-arrival of minimum ionizing particles with a resolution of 30 - 40 ps at the beginning of HL-LHC operation. The information provided by the MTD will help disentangle ~200 nearly simultaneous pileup interactions occurring in each bunch crossing at LHC by enabling the use of 4D reconstruction algorithms. The MTD will be composed of an endcap timing layer (ETL), instrumented with low-gain avalanche diodes, as well as a barrel timing layer (BTL), based on LYSO:Ce crystals coupled to SiPMs. In this talk, we will present an overview of the MTD design, highlight the new physics capabilities provided by the MTD, describe the latest progress toward production, and show test beam results demonstrating the achieved target time resolution.

Speaker: Chang-Seong MOON (Kyungpook National University)

2024.04.18 AFAD 2024 - Chang-Seong_Moon_v2.pdf

12:00 Research and Development of the ALICE Inner Tracking System 3 in Korea

The ALICE (A Large Ion Collider Experiment) collaboration is gearing up for an upgrade of the Inner Tracking System (ITS2) during the LHC Long Shutdown 3 (2026 - 2028). The upgrade will replace the three innermost layers of ITS2 with a truly cylindrical vertex detector, ITS3. This innovative tracker is composed of a 65 nm CMOS Monolithic Active Pixel Sensor (MAPS) employing stitching technology to produce a large sensor size O(10 x 26 cm$^{2}$). Its ultra-thin thickness, O(20 - 50 $\mu$m), allows flexibility to be bent into a half-cylindrical shape without additional supporting material. Finally, the three layers of the tracker consist of only six silicon sensors and light carbon forms to hold each layer to keep it in shape and location.

This detector configuration of ITS3 can reduce the material budget to 0.07\% X$_{0}$ per layer. As a result, it foresees the tracking performance, in particular at low transverse momentum ($p_{\text{T}} >$ 0.1 GeV/\textit{c}), is improved by a factor of 2 to the current ITS2. The development and validation of the sensor technology are in progress, with the prototype sensors from the first and the second test production runs: Multi-reticle-Layer Run 1 (MLR1) and Engineering Run 1 (ER1). Sensor design and its characteristics fabricated with 65 nm CMOS technology are the main interests in MLR1 prototypes whereas the validation of stitching technology is a crucial task in the R\&D with the ER1 ones.

This talk will introduce the design and structure of ITS3 and discuss extensive R\&D for bent MAPS detectors focusing on the Korean ALICE ITS3 team's activities.

Speaker: Jiyoung Kim (Inha University (KR))

20240418_AFAD2024_ITS3overviewKorea_upload-wobackup.pdf

11:20 → 12:20 WG5

Chair: Hsin-Pai Hsueh, NSRRC

11:20 Injection and fast extraction systems for J-PARC main ring

In 2023 J-PARC Main Ring achieved 750kW beam power for T2K neutrino experiment. The 750kW is the initial design value of MR and it means to reach a great milestone. In this talk, I will briefly introduce the key technologies needed to achieve this 750kW. One of the key technologies is the injection and extraction systems. The kicker magnet and power supply, septum magnet and power supply used in the systems will also be mentioned.

Speaker: Koji ISHII (KEK/J-PARC)

240418ki.pdf 240418ki.pptx

11:40 COMMISSIONING STATUS OF THE RAON SUPERCONDUCTING ACCELERATOR

The Rare isotope Accelerator Complex for ON-line experiments (RAON) is a heavy-ion accelerator for researches using Rare Isotopes (RI) as a major research facility in Korea. It can deliver ions from hydrogen (proton) to uranium. Protons and uranium ions are accelerated up to 600 MeV and 200 MeV/u respectively. It can provide various rare isotope beams which are produced by isotope separator on-line system. The RAON injector has undergone a successful commissioning process, demonstrating operational efficiency. The commissioning efforts involved a comprehensive study of the beam parameters derived from key technical systems, including the Electron Cyclotron Resonance (ECR) ion source and Radio-Frequency Quadrupole (RFQ). Moreover, the commissioning process extended to the low-energy superconducting linac (SCL3), which has also been successfully commissioned. In this paper, we present the current beam commissioning status of the RAON injector and superconducting accelerator.

Speaker: Hyung Jin Kim (Institute for Basic Science)

RAON-Status-pptx_hjkim.pptx

12:00 Key issues and feasibility scheme for the CSNS RCS upgrade

For the China Spallation Neutron Source (CSNS), the rapid cycling synchrotron (RCS) accumulates and accelerates the injection beam to the design energy of 1.6 GeV and then extracts the high energy beam to the target. As the second phase of the CSNS, CSNS-II will achieve a beam power on the target of 500 kW. The injection energy of CSNS-II will be increased from 80 MeV to 300 MeV and the injection beam power will be increased about 20 times. In this paper, for the CSNS-II，the upgrade of the RCS will be introduced and studied in detail, including the new injection system, new dual harmonic cavity, main magnet power supplies upgrade, new collimation system, beam instability, space charge effects, and so on. In order to meet the requirements of beam power increase and stable operation, the RCS beam losses from different sources are studied and optimized. Based on the detailed simulation results and beam experimental results, the feasibility upgrade schemes of the critical systems for the CSNS RCS will be given.

Speaker: Dr Ming-Yang Huang (Institute of High Energy Physics, Chinese Academy of Sciences)

AFAD-WG5-huangmy.PPTX

11:20 → 12:20 WG7

Chair: Huang-Hsiu Tsai, NSRRC

11:20 Cryomodule test facility for ITN

The ILC (The International Linear Collider) project has not yet started, however basic technology development must continue.
ITN (ILC Technology Network) is an international framework for carrying out technology development.
ITN is a project that started in FY2023 and will continue for five years.
Several technical issues have been proposed as development items at ITN, and each item will be developed through international cooperation.
One of the technology development items includes manufacturing, cooling, and RF testing the cryomodule.
The cryogenic group will need to install new equipment to cool the cryomodules.
The refrigerator (Linde LR280) currently operating at KEK will be dedicated to ITN.
Since the cryomodule test stand and the helium refrigerator are approximately 100 meters apart, installing a transfer line to transfer the liquid helium is necessary.
Additionally, the installation of 2K refrigerators, vacuum pumps, in-line purifiers, etc. is also considered.

Speaker: Kota NAKANISHI (KEK)

AFAD_WG7_nakanishi.pdf

11:40 A 230 MeV superconducting isochronous cyclotron for proton therapy SC230

A 230 MeV superconducting cyclotron SC230 is currently the most compact isochronous cyclotron for proton therapy, with a yoke diameter, height and weight of 2.8 m, 1.7 m and 65 t, respectively. It has cryogen-free superconducting coils to generate a high magnetic field. It also features a high beam current of up to 1 μA and low power consumption of its system below 200 kW. The development process and superconducting technology in SC230 are reported.

Speaker: Yuta Ebara (Sumitomo Heavy Industries, Ltd.)

AFAD2024_ebara_rev0.pdf

12:00 Development of Skeleton Cyclotron with HTS Magnet System for Medical Use

High-field cyclotron systems are strongly demanded for multi purposes: PET, targeted $\alpha$-particle therapy, etc. To install such systems into hospitals, as light weight and compactness are also required, we have been developing a new coreless cyclotron system with high-temperature superconducting (HTS) magnet, named “Skeleton Cyclotron.” The coreless cyclotron has a superior feature of variable energy for multi purposes.
In the presentation, we will show the experimental and simulation results for development of 1/2-scale demonstration HTS coils called “Ultra-Baby Skeleton Cyclotron (UBSC)” as the progress of this project.

Speaker: Prof. So Noguchi (Hokkaido University)

AFAD2024s.pptx

12:30 → 13:30 Lunch

13:30 → 15:30 WG2

Chair: Chang-Seong Moon, KNU

13:30 Fluorescence diamond EUV/soft X-ray imaging sensor development

We have achieved a groundbreaking demonstration of utilizing FNDs as scintillators for imaging synchrotron-based EUV radiation. The carbon-based scintillator comprises an ensemble of NV0 centers serving as the primary source of light emission upon above-bandgap excitation (energy > 5.47 eV or wavelength < 227 nm) within the diamond matrix. These centers exhibit exceptional characteristics, including high photostability, minimal afterglow, and a fluorescence decay time of less than 30 ns.
Our research begins with the creation of a uniform thin film of FNDs, each approximately 100 nm in diameter, on an ITO-coated glass substrate via electrospray deposition. This film, about 1 µm in thickness, possesses non-hygroscopic properties, is compatible with vacuum environments, highly durable, and emits red fluorescence from the NV0 centers upon exposure to synchrotron radiation in the EUV region. We successfully capture and image the beam characteristics, encompassing dimensions, positions, intensity profiles, divergence, and pointing stability, of radiation at wavelengths of 13.5 nm on the fluorescent screen. These images are then recorded using a visible camera. Importantly, these operational principles and methodologies can be extended to the sensing and imaging of VUV and soft X-rays.

Speaker: Dr Teng-I Yang (Taiwan Instrument Research Institute)

13:50 R&D of Barrel Imaging Calorimeter for the ePIC experiment

Electron-Ion Collider (EIC) is a new collider to explore the fundamental structure and dynamics of matter in the visible world. The EIC project includes a general-purpose detector: The ePIC Detector. The unique physics goals at the Electron-Ion Collider lead to specific design considerations for the electromagnetic calorimeter in the barrel region. The Barrel Imaging Calorimeter comprises silicon layers using the AstroPix sensors for position measurement, and bulk Pb-SciFi layers for energy measurement. Precise measurement of electron energy and shower profile will enable us to distinguish electrons from pions and to identify photons from pion decays. This talk will provide a plan and current R&D effort from Korean institutions for the ePIC Barrel Imaging Calorimeter. Korean institutions plan to contribute to the mass chip test and module assembly of the silicon layers. In addition, the production of a Pb-SciFi prototype is ongoing for further study including readout box, calibration, and integration with a silicon layer.

Speaker: Jeongsu Bok (Pusan National University)

AFAD2024_jbok_BIC4.pdf

14:10 Research and Development of industrialization of module assembly for the ALICE 3 Outer Tracker

ALICE 3 is the next-generation heavy-ion experiment proposed for the LHC Run 5 and 6. Its tracking system will be based on a vertex detector, integrated into a retractable structure inside the beam pipe to achieve the best possible pointing resolution, and a large outer tracker, surrounding the vertex detector and covering about eight units of pseudorapidity ($|\eta|<4$). The tracking system will be based on Monolithic Active Pixel Sensor (MAPS) technology. It will leverage the sensor developments carried out for the recently upgraded ALICE Inner Tracking System and the future ALICE ITS3. The total area of the ALICE 3 silicon tracker is about 60 m$^{2}$, a factor of five larger than the ALICE ITS2, so one of the challenges is a mass chip test and module assembly. The Korea ALICE group has started R\&D to utilize an automatic die-attach machine, which is generally used for semiconductor packaging in the industry. This talk will discuss R\&D activities from the Korea ALICE group on the industrialization of module assembly for the ALICE 3 Outer Tracker.

Speaker: Jiyoung Kim (Inha University (KR))

20240418_AFAD2024_ALICE3overviewKorea_upload-wobackup.pdf

14:30 Construction of an electromagnetic calorimeter prototype using LYSO crystals for the ZDC at ePIC

The Electron-Ion collider (EIC) is designed to collide spin-polarized beams of electrons and ions to study with precision the dynamics of gluons and sea quarks and their role in the structure of visible matter. The ePIC is a general-purpose large-acceptance detector and will be the first experiment operated at the EIC. For studies aiming at the three-dimensional structure of nucleons and nuclei and gluon density saturation. It requires the identification of far-angle photons and tagging spectator neutrons. Zero Degree Calorimeter (ZDC) is proposed to achieve reasonable energy resolution for neutrons(~beam energy) and photons(0.1 to 40 GeV), respectively. The position resolution is also asked to be better than 3mrad/sqrt(E) for neutrons and 1mm for photons. We developed the first electromagnetic calorimeter prototype using 64 LYSO crystals, each size 7.12mm x 7.12mm x 88mm, and SiPMs for the ZDC. The calibration was done with Co60 and Na22 radiation sources. This February, a beam test was performed in ELPH in Japan with 50MeV to 823MeV positron beam. The results from the calibration and test beam will be shown in this presentation.

Speaker: Dr Kai-Yu Cheng (Academia Sinica)

2024AFAD_ePIC_ZDC_LYSO_kycheng.pdf

14:50 Development of new optical readout concept in the visible range for dark matter detectors

Liquid argon detectors are used in a variety of fundamental physical experiments, such as dark matter searches and neutrino studies. The use of argon as a target medium is largely due to its high light yield. However, the maximum emission intensity occurs at a wavelength of 128 nm, which is difficult to detect with high efficiency. The standard solution is to use wavelength shifter, which re-emits 128 nm into the visible range, but it has its own drawbacks. In this paper, an alternative readout concept is considered, namely light readout in the visible and infrared range without wavelength shifter. The results of measurements of the light yield of primary scintillations (S1) in liquid phase and electroluminescence (S2) in gaseous phase in pure argon and their mixtures with methane are presented. Possible applications of this new readout concept in dark matter detectors and neutron veto detectors are also discussed.

Speaker: Vladislav Oleynikov (Budker INP)

AFAD2024_Oleynikov_BINP.pptx

15:10 MPGD Production capability and R&D plan in Korea

Korea CMS is one of the only two organizations, along with CERN micro pattern technology workshop, capable of producing large GEM foils, playing a crucial role in the CMS GEM upgrade. To achieve this, it has built the world's first large GEM production facility using the double-mask etching technology, which is suitable for faster production. The validation results and mass production progress of GEM foils produced in Korea will be reported. Additionally, R&D plan for the production of uRWELL, the next-generation micro pattern gaseous detector, by expanding the established capabilities will be presented. This R&D effort aims to supply uRWELL for the DAMSA experiment, a new venture in search for axion-like particle and dark photon, with the potential to also contribute to the ePIC experiment.

Speaker: Inseok Yoon (Seoul National University)

AFAD_INSEOK_240415.pdf

13:30 → 15:30 WG4

13:30 Clustering of macroparticles in simulations of plasma wakefield acceleration

Simulations of plasma wakefield acceleration are challenging for many reasons, one of which is that the wave scale (about plasma skin depth) is much larger than the Debye length. Attempting to resolve both would make simulations prohibitively expensive. Therefore, grid steps far exceeding the Debye length are used, which compromises the accuracy of PIC simulations. While this inconsistency does not notably impact short-term processes spanning several wave periods, long-term simulations lead to clustering and unphysical heating of plasma electrons.
The latter undesirable effects can be avoided by slightly modifying the law of plasma particle motion, which is implemented in the newly developed 3d version of LCODE. The new feature enables much cleaner simulations of long-term wave evolution. In particular, when the numerical heating of plasma electrons is suppressed, the wake chaotization and premature transverse wavebreaking of a moderately nonlinear plasma wave disappear.

Speaker: Konstantin Lotov (Budker INP)

2024-04-18 AFAD (noise).pptx

13:50 Assessing Wake-T as a lightweight simulation tool for beam driven plasma wakefields, with applications to compact particle accelerators.

Plasma wakefield acceleration is a promising technology for compact particle acceleration, experimental results demonstrating a high-quality beam reaching 1GeV energy in just 3.3cm [1]. Simulations are a key tool used to develop our understanding of plasma wakefield technologies, however, conventional particle-in-cell (PIC) codes can be arduous to run, requiring significant computing power.

Wake-T is a lightweight alternative to other PIC codes, boasting the ability to run these simulations in just minutes on a laptop, by considering simplified models for the plasma wakefields rather than computing full PIC plasma simulations [2]. This study assesses the use of Wake-T for simulating beam-driven plasma wakefields, with a focus on long drive-beams. The results are benchmarked against existing results [3, 4, 5] done using the spectral, quasi-cylindrical code FBPIC, which computes the full PIC simulation for the background plasma [6]. We also assess the functionality of Wake-T to perform sweeping parameter scans that would otherwise be prohibitively computationally expensive, to further analyse relationships between initial beam-plasma parameters and the development and evolution of the plasma wakefields and the particle beam.

In this work, we leverage Wake-T simulations to investigate the effect of the initial beam properties (i.e. size and emittance), and the effect of background plasma density and profile on the mutual evolution of the plasma wakefields and particle beam. Consideration is also given to long-drive beams with beam lengths in the millimetre range and much longer than the plasma wavelength, such as those commonly sourced from thermionic RF or DC guns.

[1] W. P. Leemans, et al., Nature Physics 2, 696–699 (2006).

[2] A. Ferran Pousa, R. Assmann, A. Martinez de la Ossa, Journal of Physics: Conference Series 1350, 012056 (2019).

[3] O. Jakobsson, et al., Plasma Physics and Controlled Fusion 61, 124002 (2019).

[4] M. Gross, et al., Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 740, 74 (2014).

[5] K. Moon, J. Jeong, C. Sung, M. Chung, Journal of the Korean Physical Society 83, 614 (2023).

[6] R. Lehe, M. Kirchen, I. A. Andriyash, B. B. Godfrey, J.-L. Vay, Computer Physics Communications 203, 66 (2016).

Speaker: Theo Williams (James Cook University)

AFADpptTW.pptx

14:10 Narrowband terahertz sources based on laser-plasmas for compact accelerators

Terahertz (THz)-driven accelerators are emerging as promising compact particle accelerators. By using higher frequency drivers, the threshold of vacuum breakdown can be significantly increased. Consequently, it is anticipated that the accelerating gradient can be enhanced, projecting an increase from the current 100 MV/m-order to 1 GV/m-class. To generate the high-field THz waves, laser-driven plasma schemes have been studied. However, these schemes typically produce broadband emissions, lacking the necessary high spectral density at a specific wavelength. Here we introduce novel methods aimed at concentrating THz energy into a narrow bandwidth by developing plasma oscillators. Traditional plasma-based narrowband THz sources focused on converting a plasma wave into an electromagnetic wave, but encountered challenges related to conversion efficiency. Here, we propose methods for generating plasma oscillators capable of emitting THz waves through a multipole radiation mechanism. Our approach involves two distinct schemes: plasma dipole oscillation and radially oscillating plasma oscillators. Numerical simulations confirm that both schemes effectively emit THz waves with field strengths of GV/m level and narrow spectra (<10%). Furthermore, we present preliminary studies showcasing electron acceleration using these THz waves, employing the ELEGANT code.

Speaker: MinSup Hur (UNIST)

14:30 The beam synchronized data acquisition system for CSNS accelerator

The China Spallation Neutron Source (CSNS) delivers a pulsed neutron beam at a 25Hz repetition rate, necessitating precise data synchronization for effective beam state analysis and fault diagnosis. This work presents the development of a Beam-Synchronized Data Acquisition (BSDAQ) system tailored for the CSNS accelerator. The BSDAQ system is engineered to selectively capture critical operational data, thereby enhancing the understanding and optimization of accelerator performance. To address the challenges of network bandwidth and data storage constraints, the system adopts a trigger-based data collection strategy. It features dual modes of operation: a periodic trigger for consistent data sampling and a random trigger for capturing data during specific events. The system ensures high-precision data capture, timestamping, and alignment with the beam pulse cycle, followed by storage in database. An intuitive interface for data access is also integrated to support in-depth offline analysis. The prototype BSDAQ has been successfully deployed at the CSNS, revealing previously undetectable phenomena such as intra-pulse beam chopping and automatic beam recovery post fast protection system activation. These insights are pivotal for advancing beam control strategies and bolstering the reliability of the accelerator's operations.

Speaker: Mr Cheng Sinong (IHEP, CAS)

14:50 Development and applications of segmented capillary gas-cell with tailoring longitudinal density profiles

We have developed a new segmented capillary gas cell for laser wakefield acceleration (LWFA) and plasma lenses. This capillary enables the tailoring of longitudinal density profiles in gases or plasmas, with a transverse guiding structure when discharged with high-voltage pulses. For instance, a down-gradient density profile can be used for controlled injection in LWFA. We tested this segmented capillary gas cell using a 150 TW laser system at IBS in GIST, which resulted in a reduced energy spread of the electron beam. We also measured the longitudinal plasma density profile of the discharged capillary plasma density using the Stark broadening of hydrogen gas. This novel capillary has potential applications in LWFA, PWFA, and plasma lenses with a controllable density profile. In this presentation, we will discuss the development of the segmented capillary, recent experimental results from LWFA, and its future applications.

Speaker: Dr Inhyuk Nam (PAL, POSTECH)

AFAD2024_ihnam.pdf

15:10 Electron bunch shaping by laser heater for attosecond XFEL

The pulse duration of the X-ray free-electron laser (XFEL) relies on the pulse duration of the light source, which commonly is an electron bunch. The energy and the current distributions of the electron bunch can be manipulated by using the laser heater in the purpose of generating attosecond pulse duration electron bunch. Therefore, the resultant electron bunch current profile after the bunch compressor chicane right behind the laser heater is programmable by the laser parameters. We performed the electron bunch shaping experiment by using the laser heater at PAL XFEL. The parameter dependencies of the laser heater shaping are discussed based on analytical and numerical approaches.

Speaker: KOOKJIN MOON (PAL, POSTECH)

AFAD-WG4_K.Moon.pptx

13:30 → 15:30 WG7

Chair: Huang-Hsiu Tsai, NSRRC

13:30 Study on Multipacting Events in SRF Operation at NSRRC

The NSRRC operates two synchrotron radiation light sources, Taiwan Light Source and Taiwan Photon Source. Both sources employ superconducting radio frequency (SRF) cavities. Recently, occurrences of multipacting events have been encountered during the operation of the SRF modules in both sources, leading to operational challenges. In this report, we provide an overview of the SRF modules in both sources, investigate the multipacting events, and propose potential improvement solutions.

Speaker: Dr Zong-Kai Liu (NSRRC)

2024-0418-NSRRC_RF.pptx

13:50 Progress of HEPS Cryogenic System

High Energy Photon Source (HEPS) is a high-performance and high-energy synchrotron radiation light source with a beam energy of 6GeV and an ultra-low emittance of better than 0.06nm×rad. The HEPS is mainly composed of accelerator, beamlines and end-stations.The cryogenic system includes a helium refrigerator system and a nitrogen cryogenic plant. The helium refrigerator system has been consisted of a helium refrigerator on a capacity at 2000W@4.5K, a cryogenic distribution transfer system and helium recovery and purification system for 10 superconducting radio frequency cavity cryomodules. The pressure stability at ±1.50mbara of the low pressure in helium compressors has achieved, which is a great significance to these superconducting radio frequency cavities. The nitrogen cryogenic plant is crucial for creating and maintaining operational conditions of the thermal shield of superconducting radio frequency cavity cryomodules, precooling the helium refrigerator coldbox, cooling photon beamline cryostats and cryogenic inserts in the HEPS. The nitrogen cryogenic plant has an average capacity about 50kW at 80K in the HEPS phase I. The nitrogen cryogenic plant is mainly included of nitrogen cycle refrigerator system at 7000W@90K and 100Nm3/h, two liquid nitrogen tanks and cryogenic fluid distribution tube network. The HEPS project engineering implementation has started at June 2019 and will be finished in the end of 2025. The Schematic diagram, status and recent machines commissioning of the cryogenic system are described in this paper.

Speaker: Rui Ge (IHEP， CAS)

AFAD2024-Progress of HEPS Cryogenic System.pdf

14:10 Investigation on the zero liquid helium consumption cryostat for a superconducting undulator

Superconducting undulators have become a research hotspot of the insertion devices in the synchrotron radiation facility. However, the cryostat, which is used to create a liquid helium temperature environment, often causes the failure of the superconducting undulator. In this work, a cryostat with a new refrigeration distribution for a superconducting undulator is designed, fabricated and tested. For the cooling of the superconducting magnet, a liquid helium circulation loop based on the thermosiphon effect is designed with no moving component. The systematic thermal analysis and optimization are carried out to minimize the total heat load. The cooling capacity matches the heat load at different temperatures well and the theoretical excess cooling capacity is increased. In the experiment, the cryostat was tested with several superconducting magnets. There was no liquid helium consumption with excess cooling capacity in the test. Finally, the superconducting magnet reached a direct current of more than 450 A. This study can be a reference for the development of superconducting undulator cryostats.

Speaker: Dr Zhang Xiangzhen (IHEP, CAS)

Investigation on the zero liquid helium consumption cryostat for a superconducting undulator.pdf

14:30 High quality factor and accelerating gradient of 650 MHz superconducting cavity for CEPC

The 650 MHz single-cell superconducting radio-frequency (SRF) cavities used for the Circular Electron Positron Collider (CEPC) were studied to achieve a high accelerating gradient (Eacc) and high intrinsic quality factor (Q0). The 650 MHz single-cell cavities were subjected to a combination of buffered chemical polishing (BCP) and electropolishing (EP), and their Eacc exceeded 40 MV/m. Such a high Eacc may result from the cold EP with more uniform removal. BCP is easy, cheap, and rough, whereas EP is complicated, expensive, and precise. Therefore, the combination of BCP and EP investigated in our study is suitable for surface treatments of mass SRF cavities. Medium temperature (mid-T) furnace baking was also conducted, which demonstrated an ultrahigh Q0 of > 8E10 at 22 MV/m, and an extremely low BCS resistance of ~ 1.0 nΩ was achieved at 2.0 K. The study of CEPC 650 MHz SRF cavities may benefit SRF community, which has been referenced by PIP II.

Speaker: Prof. Peng Sha (IHEP, CAS)

High quality factor and accelerating gradient of 650 MHz superconducting cavity for CEPC.pptx

14:50 Progress of the High Field Superconducting Magnet Program at IHEP-CAS

High energy proton colliders towards 100 TeV are proposed these years to study the physics beyond the Standard Model. The colliders call for 16-20 Tesla (T) accelerator magnets to bend and focus the particle beams. IHEP-CAS has been engaged in developing high field magnet technology with Nb3Sn and HTS materials from 2014: several model dipoles have been developed with combined common coil configuration, and advanced iron based superconducting (IBS) technology is being promoted in collaboration with IEE-CAS. The highest field of model dipoles reached 12.47 T in two apertures at 4.2 K with Nb3Sn and NbTi coils. A new model dipole aiming for 16 T in the aperture is under fabrication. The magnet consists of 6 Nb3Sn coils and 4 HTS coils: the Nb3Sn coils with common coil configuration are expected to provide a dipole field of 13~14 T, and the HTS insert coils wound with block configuration and a new type of transposed ReBCO cable are expected to provide a dipole field of 3~4 T with 13-T background field. Moreover, development of high current IBS cables and high field model coils are ongoing: 1.3 kA IBS transposed cable has been successfully fabricated, and the IBS model coils reached 60 A critical current at 32 T background field. An overview of the high field magnet program at IHEP-CAS, present progress and the plan for future will be presented.

Speaker: Qingjin XU (IHEP-CAS)

HF Magnet Program at IHEP-CAS -Apr 2024.pptx

15:10 Development of the Liquid Nitrogen Transfer line for TPS Beamline Endstation

In 2015, Taiwan Photon Source (TPS) successfully completed a significant project involving the installation of a crucial 600-meter-long liquid nitrogen (LN2) transfer line specifically designed for beamline endstations. This line previously supplied liquid nitrogen to a maximum of 24 beamline endstations. Subsequently, in 2018 and 2019, Beamline Endstation 13A was inaugurated, focusing on advanced and general studies of biological structures and structural kinetics in solution or condensed forms under environmental simulations. The research spans from atomic to micrometer scales with a time resolution ranging from microseconds to minutes. To meet the specific requirements of Beamline Endstation 13A, we independently designed and manufactured a dedicated LN2 transfer line to supply liquid nitrogen to the double-crystal monochromator (DCM), effectively addressing crystal thermal deformation issues. Additionally, we innovatively designed a keep-full device to replace the phase separator of the chiller. This paper will provide a detailed introduction to various aspects of this transfer line, including pipeline design, performance testing, the keep-full device, pressure reducer, noise reduction measures, and heat-load measurements.

Speaker: Wun-Rong Liao (NSRRC)

2024-04-18_WG7_rev1.pptx

15:30 → 16:00 Coffee Break

16:00 → 17:00 WG2

Chair: Chang-Seong Moon, KNU

16:00 Development of micro-pattern gaseous TPC for direction-sensitive dark matter search

The sensitivity of the direct dark matter search is being improved by various energy-sensitive experiments such as XENONnT, LZ, Panda-X and so on. On the other hand, in order to reveal properties of the dark matter particle after its discovery or to explore beyond the neutrino-fog region, direction-sensitive dark matter search is designed and taken place recently.The 3D tracking technology of nuclear recoils induced by dark matters allows to measure the directionality of dark matters.One of the method to reconstruct nuclear recoils' track is the use of low-pressure gaseous TPC with micro-pattern readout.In this talk, we report the recent activities of the development of low-pressure gaseous TPC's used for direction-sensitive direct dark matter searches in the world, especially for our experiment: NEWAGE.

Speaker: Satoshi Higashino (Kobe University)

higashino_AFAD2024_20240418.pptx

16:20 Neutron Detection Study from Beam test of Boron GEM detector

The GEM neutron detector incorporates a layer of boron for neutron capture.
The aim is to offer more cost-effective and larger-scale coverage for neutron detection compared to conventional cold neutron detectors.
We present the results of the beam test using cold neutrons (10 meV) at HANARO (High-Flux Advanced Neutron Application Reactor), analyzing the hit positions of the neutron beam and the signal waveform.

Speaker: WooJong Kim (University of Seoul)

AFAD2024_Neutron Detection Study from Beam test of Boron GEM detector_Woo-Jong Kim.pdf

16:40 R&D of Fast Timing Multi Anode MCP-PMT for Radiation Imaging

The time performance of photodetector is a critical parameter for the development of Radiation Imaging Detectors based on time of flight (TOF) technique, for example TOF positron emission tomography (TOF-PET). In 2020, the proposal of roadmap toward the 10 ps TOF-PET challenge places higher requirement on the time performance of the photodetector. Microchannel Plate Photomultiplier (MCP-PMT) is a popular candidate photodetector of TOF-PET for its high gain, good detection efficiency, single photon detect ability, magnetic field resistance, ultimately its good time resolution and spatial resolution.
This manuscript introduces the R&D of fast timing MCP-PMT with 8*8 anodes with a rise time (RT) less than 300 ps and Transit time spread (TTS) less than 40 ps under single photon mode. In addition to the performance evaluation of the MCP-PMT itself, the performance of this kind of MCP-PMT coupled with crystal array also be calibrated under proton and neutron beam respectively, including the energy resolution and uniformity, the time resolution and uniformity. The experiment is in progress, and the relevant results are being analysed step by step, and the full results will be presented in a formal report or article.

Speaker: Dr Ma Lishuang (IHEP，CAS)

16:00 → 17:20 WG5

Chair: Hsin-Pai Hsueh, NSRRC

16:00 Development of long life-time RF-driven negative hydrogen ion source in CSNS

To meet the 500kW beam power requirement of China spallation neutron source project Phase-II (CSNS-II), an external antenna RF-driven negative hydrogen ion source has been developed. It has been put into commissioning on China spallation neutron source (CSNS) accelerator since September of 2021. In the last two run cycles, it has operated for 315 days and 323 days respectively, with 100% availability. This report covers the recent research and development of the RF-driven H$^-$ source and low energy beam transport (LEBT) designed for CSNS-II. A featured function of the LEBT is the electrostatic beam chopping. The influence of chopping electric field to the space charge compensation is also experimentally studied.

Speaker: Dr Weidong Chen

Chenwd-AFAD2024.pptx

16:20 Efficient usage of neutron beams

Since neutrons are secondary particles, their efficient use is important in applications. Even neutrons, which have no electric charge, can be deflected by magnetic fields due to their magnetic dipole moment. Transport and manipulation of neutron beams using magnetic fields will be discussed.

Speaker: Yoshihisa Iwashita

AFAD204_WG5_Iwashita.pdf

16:40 A Design Study of Accelerator Neutron Sources on Neutron Beam Utilization for Post Kyoto University Research Reactor

There are two research reactors at the Institute for Integrated Radiation and Nuclear Science, Kyoto University (KURNS). Kyoto University Research Reactor (KUR) of one of the reactors, which has a thermal output (5 MW), is scheduled to be shut down in May 2026. The KUR has been used for many years as a neutron source for collaborative research, and we are considering the construction of a general-purpose accelerator neutron source using the existing 30MeV proton cyclotron (HM-30) for the BNCT as an alternative neutron source after the KUR is shut down. The problems in promoting this project are the operating cost of the HM-30 and the running cost of the neutron generation target. Therefore, we have started to consider the construction of a small neutron source using 11MeV H- Linac manufactured by AccSys, which has been used as an injector for the FFA accelerator at KURNS. In this presentation, we will report on the status of the investigation of accelerator neutron sources at the KURNS.

Speaker: Yasutoshi Kuriyama (Kyoto University)

kuriyama_kyoto_wg5_r3.pdf

17:00 Design and beam dynamics study of a multi-functional MEBT for CSNS

The CSNS is an accelerator-based multidisciplinary user facility operates at a stable beam power of 140 kW since October 2022, which is 40% higher compared to the designed value. The upgrading project of CSNS (CSNS-II) is in progress, and the missions associated with linac include increasing the output energy to 300 MeV by employing superconducting accelerator and the peak current to 50 mA. A multi-functional MEBT has been studied and redesigned to meet the stringent demand of beam control under strong space charge effects. The MEBT can be characterized by the following main functions and features: (1) beam chopping for time structure optimization; (2) collimator for beam halo particle confinement and removal; (3) phase shift optimization and rigorous control of entire length to achieve low emittance growth transmission within the MEBT. The beam performance and error studies together with the main linac have been conducted and shown in this article. Numerous multi-particle simulations have shown that the multi-functional MEBT can prevent unacceptable beam loss in the main linac.

Speaker: Dr Qiyu Kong

AFAD2024-20240418-CSNS-MEBT-WG5-72-QiyuKong.pdf

16:00 → 17:20 WG7

Chair: Huang-Hsiu Tsai, NSRRC

16:00 Helium Recycling Initiatives at RIKEN in Japan

Helium has excellent properties that cannot be replaced by other substances, such as complete inertness, cryogenic boiling point, high thermal conductivity, low density, low solubility, high diffusivity, non-irritant properties, and low viscosity. Helium is used in medical field to cool superconducting magnets in MRI, in industry for optical fiber and semiconductor manufacturing, welding, leak testing, fillers, etc.. For academic fields, helium is one of the "lifelines" like water and electricity, is an indispensable substance in a wide range of fields such as physics, chemistry, and astronomy.
However, "helium crisis" is globally taking place, and this could become even more serious in the future. Japan is also suffering from this crisis because it relies on imports for 100% of its helium, resulting in soaring prices and supply shortages. Researchers who use helium for academic research have little access to it.
We propose and implement measures such as helium recycle system to protect academic researchers from this helium crisis.
As a start, RIKEN and a MRI company conducted a demonstration experiment successfully to efficiently recover helium, which is wasted and discarded when MRIs are renewed. In this demonstration test, the discarded MRI containing liquid helium was transported directly to RIKEN, which has a liquefied helium production facility, to recover the gas from the MRI. This dramatically improved the efficiency of helium transport.

In the future, RIKEN plans to develop inexpensive on-site refining machines for semiconductor factories and to study on helium rental service for cryogenic researchers in universities that do not have a liquefaction machine.

Speaker: Hiroki Okuno (RIKEN)

240417 AFAD2024 okuno final.pptx

16:20 Upgrade of the He cryoplant at HIAF ANU

Several aspects of the operation of ANU linac cryogenic system is discussed. We will describe the upgrade options of the 30 years old cryogenic facility.

Speaker: Nikolai Lobanov (Australian National University)

AFAD24-Upgrade ANU cryogenic plant.pdf

16:40 Design and Construction of a 1.5-GHz Two-Cell SRF Module in NSRRC

A two-cell 1.5-GHz superconducting radio-frequency (SRF) cavity was designed and optimized by NSRRC previously, and then manufactured by Mitsubishi Heavy Industry Machinery Systems (MHI MS), Japan. Following post processes on this SRF cavity such as electrical polishing (EP), annealing, and pre-tuning, had been finished in KEK, Japan in 2023 under a cooperation agreement between NSRRC and KEK. This SRF cavity’s frequency of pi-mode was successfully tuned to the expected frequency range, by applying a longitudinal displacement on its structure to elastoplastic range. It is the first time to practically tune the resonance frequency of an SRF cavity with its interior in vacuum, as to eliminate the effect of air’s permittivity on measured resonance frequency. Meanwhile, the cryostat for this SRF cavity was designed by NSRRC and contracted to local companies. The helium vessel has been delivered and passed the cold shock and helium leaking test, whereas the vacuum vessel is still in production. The higher-order-mode (HOM) damper is contracted to Research Instruments (RI), Germany and shall be delivered in 2024. It is expected to finish the vertical test of this SRF cavity in 2024 and the module assembly in 2025. Installation, system integration, and beam commissioning are scheduled in 2025-2026. The bunch length of stored electron beam in Taiwan Photon Source (TPS) is expected to increase with a factor of 1.6 to raise the beam life time and to reduce the beam-induced heat on the magnet arrays of the in-vacuum undulators.

Speaker: Chih-Hung Lo

AFAD_2024_WG7_Lo.pdf

17:00 Mitigating Thermoacoustic Phenomena in Cryogenic Helium Distribution System

In the operation of the cryogenic helium distribution system for TPS superconducting radio frequency (SRF) cavities, thermal acoustic oscillations (TAOs) frequently arise, causing pressure fluctuations in the cold helium gas processing lines, reaching up to 65 mbar. These TAOs introduce an additional heat load, impacting the operational stability of the SRF cavities. To address this issue, three gas buffers were affixed to the exhaust pipelines of the helium gas processing lines. The isolation valve of the gas buffers was maintained at a halfway position to mitigate pulsations in the flow. Remarkably, these buffers effectively quelled the TAO phenomena without necessitating modifications to the exhaust pipelines. Consequently, pressure fluctuations were substantially diminished, not exceeding 7 mbar, thereby meeting the operational requirements for the SRF cavities. This paper presents and deliberates on the implemented solution for mitigating thermoacoustic phenomena within the cryogenic distribution system.

Speaker: Mr Hsing-Chieh Li (NSRRC)

Mitigating Thermoacoustic Phenomena in Cryogenic Helium Distribution System.pptx

18:00 → 20:00 Banquet: Caiyuan Shanghai Restaurant

Friday, 19 April

09:00 → 10:20 Summaries and closing

09:00 Summary of WG1

Speaker: Dr Jui-Che Huang (NSRRC)

WG1-F.pptx

09:10 Summary of WG2

Speaker: Chang-Seong MOON (Kyungpook National University)

2024.04.19 AFAD 2024 - Chang-Seong_Moon_v1.pdf 2024.04.19 AFAD 2024 - Chang-Seong_Moon_v1.pptx

09:20 Summary of WG3

Speaker: Anatoly Rozenfeld (University Of Wollongong , Centre for Medical Radiation Physics)

09:30 Summary of WG4

Speaker: MING-WEI LIN (National Tsing Hua University)

AFAD-WG4-Summary_Organized.pptx

09:40 Summary of WG5

Speaker: Hsin-Pai Hsueh (NSRRC)

AFAD2024 WG5 Summary.pptx

09:50 Summary of WG6

Speaker: Go Iwai (KEK)

summary-iwai-WG6-rev4.pptx

10:00 Summary of WG7

Speaker: Kota NAKANISHI (KEK)

Summary of WG7.pptx

10:10 Closing talk

Speakers: Huang-Hsiu Tsai (NSRRC), Kota NAKANISHI (KEK)

AFAD2025.pdf closing remarks.pptx

10:30 → 12:20 Site Tour