The SCRIT electron scattering facility at RIKEN RI Beam Factory (Working group 1: Accelerator systems)

• Tetsuya Ohnishi (RIKEN Nishina center)

Room: 5F Grand Hall Electron scattering is a powerful tool for studying nuclear structure, because it allows model-independent studies of nuclear structure. For example, the charge density distribution of nuclei can be determined very accurately by electron elastic scattering. Therefore, electron scattering has been long awaited in the study of unstable nuclei, especially short-lived unstable nuclei. To realize electron scattering with unstable nuclei, a new ion trapping method, Self-Confining Radioactive Isotope Ion Target (SCRIT) method, was developed.[1] After demonstrating the principle of the SCRIT method, the SCRIT electron scattering facility was constructed at RIKEN RI Beam Factory in 2009.[2] The SCRIT facility consists of an electron accelerator, an electron storage ring equipped with the SCRIT system, an online isotope separator, and an electron spectrometer besides the SCRIT system. Produced Radio Isotope (RI) beams are injected to the SCRIT system and RIs trapped inside the SCRIT system play as stationary targets. Electron beam stored in the ring are scattered from the RI targets and analyzed by the spectrometer. After the success of the commissioning experiment using Xe [3] and the development of the RI production, the world's first electron scattering experiment using online-produced unstable nuclei was successfully conducted using Cs beam in 2022.[4] For the next stage, the upgrade of the SCRIT facility is underway for electron scattering off Sn, which is a iconic nuclei. In this contribution, we will report details of the first experiment, and the present status and perspective of the SCRIT facility. [1] M. Wakasugi, T. Suda, and Y. Yano, Nucl. Instr. and Meth. A532, 216 (2004). [2] M. Wakasugi et al., Nucl. Instr. and Meth. B317, 668 (2013). [3] K. Tsukada et al., Phys. Rev. Lett. 118, 262501 (2017). [4] K. Tsukada et al., Phys. Rev. Lett. 131, 092502 (2023).

Stabilization of ferroelectric phase in HfO2-based materials via He ion beam irradiation (Working group 4: Applications of particle beams)

• Yunseok Kim (Sungkyunkwan University)

Room: 5F Grand Hall Continuous advancement in nonvolatile and morphotropic beyond-Moore electronic devices requires integration of ferroelectric and semiconductor materials. The emergence of HfO2-based ferroelectrics that are compatible with atomic-layer deposition has opened interesting and promising avenues of research. However, the origins of ferroelectricity and pathways to controlling it in HfO2 are still mysterious. In this presentation, I will present how we are able to stabilize ferroelectric orthorhombic phase in these materials by defect engineering via local He ion beam irradiation and discuss the possible competing mechanisms for resulted highly enhanced ferroelectricity [1]. We first examine feasibility of defect engineering via local He ion beam irradiation using prototypical two-dimensional (2D) transition metal dichalcogenides (TMD) MoTe2. Then, we investigate how controlled irradiation influences on the ferroelectric phase in HfO2-based materials. Our piezoresponse force microscopy results indicate that the amplitude of piezoresponse in the ion irradiated region increased by approximately twofold compared with that in the pristine region and the scanning transmission electron microscopy results show a homogeneous distribution of oxygen vacancies and a phase transition to the ferroelectric phase. These findings both reveal the origins of ferroelectricity in this system and open pathways for nano-engineered binary ferroelectrics.

From SPring-8 to SPring-8-Ⅱ

• Takaki Hatsui (RIKEN)

Room: 5F Grand Hall

The Smart Light Source - the future vision in AI for HEPS

• Fazhi Qi (IHEP)

Room: 5F Grand Hall

Status of the RAON Experimental Systems

• Jinho Lee (Institute for Rare Isotope Science, IBS)

Room: 5F Grand Hall

Current status of SNUH Heavy Ion Therapy Gijang Center (Working group 3: Beamline and instrumentation)

• Sung Hyun Lee (Seoul National University Hospital)

Room: 5F Grand Hall The Seoul National University Hospital (SNUH) Heavy Ion Therapy Gijang Center is a national project aiming to begin treatment at the end of 2027. This project, which began in 2010 at the Korea Institute of Radiological and Medical Sciences (KIRAMS), was transferred to SNUH in May 2019. A contract with Toshiba was signed in September 2020, and it had been decided to install the synchrotron in the completed building previously planned for a cyclotron. A new gantry treatment room also has been built connecting to the existing building. Construction of the gantry room expansion has been completed in April 2025, and equipment installation has begun in May 2025. Equipment installation is scheduled until May 2026, with beam tuning beginning in February or March 2026 and expected to be completed by April 2027. Following the completion of the Acceptance Test Procedure (ATP) in May 2027 and several months of commissioning, simultaneous treatment of the horizontal port and gantry port is planned to be started at the end of 2027. This project will involve both carbon and helium ions, and the installation of a research beamline in the remaining bunker is under consideration. This presentation will briefly outline the current status of SNUH Heavy Ion Therapy Gijang Center.

The Status and Plan of Korea 4th Generation Storage Ring Project

• Cheolho Jeon (KBSI)

Room: 5F Grand Hall

Analysis of Orbit Stability under External Perturbations in Low‑Emittance Storage Rings (Working group 2: Beam physics, diagnostics and novel techniques)

• GYEONGSU JANG (Pohang Accelerator Laboratory)

Room: 5F Grand Hall The beam stability relative to the beam size is a key performance parameter for storage ring light sources. In next‑generation storage rings, the substantial reduction in natural emittance makes the electron beam orbit far more sensitive to external perturbations. As a result, orbit stability must be controlled to within only a few percent of the beam size across a broad frequency range. In this work, we investigate how ground vibrations, magnet power‑supply ripple, and RF‑induced energy variation contribute to the electron beam orbit stability as a function of frequency.

Prospects for RAON Experiments with the KISTI-6 Supercomputer (Working group 4: Applications of particle beams)

• Kihyeon Cho (KISTI)

Room: 6F Lily&Rose Hall The RAON heavy-ion accelerator facility in Korea is entering a new era of precision nuclear physics experiments. These include studies on exotic nuclei near the proton drip line. One recent large-scale computational achievement using the KISTI-5 supercomputer (Nurion, 25.7 PF) was the theoretical and simulation-based support for the determination of nuclear charge radii in neutron-deficient sodium isotopes. This project required extensive *ab initio* nuclear structure calculations and advanced reaction modeling. The calculations pushed Nurion to its computational limits. In addition, Geant4-based beam simulations were also carried out on Nurion to support the RAON experiments. These simulations provided key insights into beam dynamics and detector performance. The KISTI-6 supercomputer, providing 600 PF GPU-accelerated performance, will create unprecedented opportunities for the RAON experimental program. The massively parallel architecture and high memory bandwidth of GPU nodes will enable large-scale coupled-cluster and nuclear lattice effective field theory (NLEFT) simulations. It will also support higher-precision Monte Carlo analysis and more accurate modeling of nuclear charge radii in isotopes far from stability. We anticipate that this computational leap will not only refine the theoretical interpretation of experimental data but also guide detector design, optimize beam time usage. It will significantly improve predictive accuracy for upcoming measurements beyond the current sodium isotope study. The synergy between RAON’s experimental capabilities and the KISTI-6 supercomputer will advance nuclear structure research. It will set new benchmarks at the exascale level. It will also pave the way for discoveries in both fundamental nuclear properties and applications in astrophysical modeling.

Non-invasive beam profile monitors for the CSNS Accelerator (Working group 2: Beam physics, diagnostics and novel techniques)

• Renjun Yang (Institute of High Energy Physics/CAS)

Room: 5F Grand Hall The China Spallation Neutron Source (CSNS) is a major facility for neutron science in China, and is currently operating at an averaged beam power of 170 kW with a beam energy of 1.6 GeV and repetation rate of 25 Hz. In 2024, the CSNS Upgrade project (CSNS-II) was launched aiming to improve the average beam power to 500 kW. In the sequence, a number of new instrumentations will be equiped at the new superconducting linac, RCS and new beamlines. In this talk, we will present an overview of the new diagnostics and the corresponding the high-intensity challenges. The recent progresses on the non-invasive profile monitors, such as the ionization profile monitor and laser-wire profile monitor, will be highlighted.

Transverse Phase Space Characterization and Benchmarking Studies Using Multi-Diagnostic Techniques at the KOMAC Beam Test Stand (Working group 2: Beam physics, diagnostics and novel techniques)

• Emre Cosgun (UNIST, KAERI)

Room: 5F Grand Hall We characterize the space charge-dominated 1 MeV/nucleon proton beam at the Beam Test Stand (BTS) of the Korea Multipurpose Accelerator Complex (KOMAC) through comprehensive transverse beam diagnostics and phase space analysis. A suite of diagnostic tools, including a conventional pepper-pot (PP), virtual pepper-pot (VPP), Allison scanner, and multi-slit system, is employed to measure the beam distributions under varying space charge conditions. The dynamics and optimization of space charge compensation (SCC) in the Low Energy Beam Transport (LEBT) line are investigated through time-resolved measurements. Experimental benchmarking between the VPP and conventional pepper-pot methods demonstrates strong agreement, validating the accuracy of the multi-diagnostic approach. Furthermore, by utilizing the generative phase space reconstruction algorithm based on neural networks and differentiable simulations, we investigate the phase space reconstruction by considering both the matrix calibration and self-consistent beam propagation.

The RF power sources of CSNS-II Linac (Working group 1: Accelerator systems)

• Zhencheng Mu (Institute of High Energy Physics, CAS.)

Room: 5F Grand Hall The CSNS-II Linac consists of H- ion source, RFQ and four DTLs, twenty superconducting Spoke cavities and twenty-four superconducting Elliptical cavities. The RF frequency of the RFQ, DTLs and Spoke cavities is 324MHz, and the Elliptical cavities are 648MHz. The repetition rate of the RF pulse is 50Hz, the RF pulse width of the normal conducting is less than 900μs, and the superconducting is less than 1.2ms. The 324MHz klystron power sources provide RF power to the RFQ and DTL accelerators. The prototype of the mega-material 324MHz klystron has been developed tested successfully, the peak power can reach 3MW. The 648MHz klystron power source provide RF power to Spoke cavities, both the 324MHz klystrons and the 648MHz klystrons are provided high voltage pulse by long-pulse solid-state modulator. The Spoke cavities are powered by 324MHz/300kW solid-state RF power sources based on the GaN amplifier. The prototype of the 324MHz/300kW solid-state RF power source is also developed now, the test results satisfied the requirements of the spoke cavities.

Micro-patterned Ga2O3 Thin Films for Synchrotron X-ray Photodetectors (Working group 3: Beamline and instrumentation)

• Sukjune Choi (Gwangju Institute of Science and Technology)

Room: 6F Lily&Rose Hall Ga2O3, with its wide bandgap (4.9 eV) and high breakdown field (8 MV/cm), has been widely studied for high-power electronics and solar-blind photodetectors, and more recently explored for X-ray detection, though mostly with in-house sources. Here we demonstrate a micro-patterned device fabricated by H3PO4 wet etching at 120 °C on Ga2O3/sapphire (0001) thin films synthesized by RF powder sputtering, and evaluate its X-ray sensing under a 10 keV synchrotron micro-beam focused to ~ 10 × 30 μm2. Four-point probe measurements were performed while toggling irradiation at bias voltages from self-powered (0 – 0.1 V) up to 20 V. Compared with unpatterned devices, the micro-patterned Ga2O3 exhibits an order-of magnitude higher current gain, reaching photocurrents of ~ 1 μA, a practical detection level. The photocurrent-to-darkcurrent ratio (PDCR) improves more modestly, due to trap sites introduced at etched sidewalls, which increase the darkcurrent. Sensing responses were fitted with a simple two-component model, yielding rise and decay times comparable to unpatterned films. This indicates that micro-patterning mainly enhances collection efficiency without altering intrinsic recombination. These findings demonstrate a simple and scalable strategy to improve Ga2O3 X-ray photodetectors without complex device architectures. Detailed results on X-ray photo-current measurements will be presented.

Improvement of RAON Linac Beam Commissioning (Working group 2: Beam physics, diagnostics and novel techniques)

• Ji-Ho Jang

The RAON linear accelerator consists of an injector and a superconducting linear accelerator (SCL3). The injector is composed of an ECR ion source, LEBT, RFQ, and MEBT. The ECR ion source generates various ion beams (A/Q = 1~7.2) with an energy of 10 keV/u, and the RFQ accelerates them to 500 keV/u. The superconducting accelerator (SCL3) is composed of two types of superconducting accelerating cavities, QWR and HWR, and accelerates uranium beams up to 18.5 MeV/u. In last year’s beam commissioning of the superconducting linac using an argon beam, the measured energy was lower than expected; however, this issue has been resolved this year. In this presentation, we summarize the results of injector and superconducting accelerator beam commissioning performed this year, along with several improvements.

Dual In-Situ Transmission XRD for Perovskite Thin-Glass Encapsulation and Nylon 5,6 Drawing (Working group 3: Beamline and instrumentation)

• Kukhyun Jo (Institute of Advanced Organic Materials, Pusan National University, Busan 46241, Republic of Korea)

Room: 6F Lily&Rose Hall Analyzing material structure by X-ray diffraction in real time is crucial because it probes physical properties during deformation rather than only after the material has stabilized. To this end, we built two in-situ X-ray diffraction systems that monitor nylon 5,6 fibers and perovskite thin films, respectively. For the fibers, drawing above Tg induces polymer-chain orientation and markedly increases mechanical strength. To observe this process, we developed a heater-integrated X-ray transmission drawing stage. With the fiber axis aligned to the beam, WAXS patterns were collected, and the (004) reflections were analyzed to quantify phase fraction, orientation, and lattice strain. The results show a continuous γ→α structural transition during drawing, followed by additional growth of the α component during unloading and cooling. For the perovskite films, we measured degradation behavior in real time. Reflection-mode measurements in air often fail to secure reliable diffraction signals because the encapsulation cover perturbs the optical path. To overcome this, the perovskite was coated on ~150 μm glass and an equally thin glass was used as a cover to enable transmission. The sample was then sealed under N₂ and monitored with a transmission in-situ setup. GIWAXS tracked lattice-parameter shifts, peak-width changes, and the emergence of PbI₂ diffraction, enabling simultaneous quantification of early-stage degradation, phase segregation, and texture evolution. Leveraging these real-time in-situ methods provides structural information that explains—and helps predict—the physical properties of diverse materials.

Intelligent Design Optimization of Half-Wave Resonator (HWR): A Machine Learning-based Approach (Working group 1: Accelerator systems)

• Jeong-jeung Dang (Korea Institute of Energy Technology (KENTECH))

Room: 5F Grand Hall This study presents a methodology for the radio-frequency (RF) design optimization of a half-wave resonator (HWR) that can be used at the SCL-21 section of the RAON heavy ion accelerator. To overcome the limitations of conventional manual parameter sweep methods, such as computational inefficiency and convergence to a local optimum, we introduce a machine learning-based, data-driven optimization workflow. To build a dataset that efficiently represents the entire design space, we applied Latin Hypercube Sampling (LHS) and utilized a Support Vector Machine (SVM) classifier with probabilistic output to efficiently acquire valid CST simulation data. Based on the acquired data, we trained a Gaussian Process Regression (GPR) surrogate model with an ARD (Automatic Relevance Determination) kernel, which automatically infers the importance of each variable. The hyperparameters of this model were automatically optimized through Bayesian Optimization. Finally, we coupled the highly trained surrogate models with a Multi-objective Genetic Algorithm to derive a Pareto optimal front for the conflicting objectives of maximizing the accelerating electric field (Eacc), and minimizing the peak surface electric field ratio (Epk/Eacc) and magnetic field ratio (Bpk/Eacc). During this process, we iteratively performed adaptive sampling, which leverages the uncertainty information from the GPR models, to progressively improve the model's predictive accuracy and enhance the search for a global optimum. The proposed methodology offers a new direction for the complex field of accelerator cavity design by providing both significant design time reduction and performance enhancement, overcoming the limitations of previous experience-based design approaches.

The fabrication of 1.3 GHz single-cell cavities by using niobium materials with fine and medium grain sizes (Working group 1: Accelerator systems)

• Junho Han (Kiswire Advanced Technology Co., Ltd.)

Room: 5F Grand Hall As a part of research into the fabrication methods for SRF (superconducting radio frequency) cavities used in ILC (International Linear Collider), two 1.3 GHz single-cell cavities have been fabricated successfully by using niobium materials with different grain sizes; fine grain (ASTM 5-6) and medium grain (ASTM 0-3). Both cavities have been fabricated using identical manufacturing equipments. After fabrication, They are shipped to KEK in Japan to conduct the surface treatments and VT (vertical test). We present a comprehensive overview of the cavity fabrication process and the performance test results in cryogenic temperature.

Agentic AI, Physical AI, AI Scientist, and Superfacility for Accelerator Facilities (Working group 2: Beam physics, diagnostics and novel techniques)

• Yujong Kim (KAERI & UST)

Room: 6F Lily&Rose Hall Recent progress in Artificial Intelligence (AI) has accelerated the development of high-performance Large Language Models (LLMs), with leading global companies releasing new generations every few months. The emergence of GPT-5, exhibiting expert-level reasoning capabilities, has reduced hallucination errors to only a few percent, suggesting the feasibility of near-zero-hallucination LLMs in the near future. This rapid advancement is reshaping the research landscape, where tasks once requiring large teams can now be executed by a single expert working collaboratively with an intelligent AI Scientist. In accelerator science, Agentic AI and Physical AI are being introduced to enhance accelerator design, diagnostics, autonomous operation, fault detection, and predictive maintenance. To maximize scientific productivity, the Superfacility concept integrates accelerator beamlines, high-performance computing (HPC), big-data centers, and AI platforms through high-speed networks, enabling autonomous and data-driven experimentation. In this paper, we present our recent developments of ELEGANT–LLM–based Agentic AI, designed to estimate magnetic-field and alignment tolerances and to improve the dynamic aperture of the Korea-4GSR light source project. We also describe EPICS–LLM–based Physical AI for autonomous accelerator operation. Furthermore, the concepts of the AI Scientist and Advanced Superfacility platform for accelerator beamlines are introduced, demonstrating the potential of AI-driven accelerator facilities in achieving intelligent, self-optimizing research infrastructures.

Overview of the Korea-4GSR LINAC System (Working group 1: Accelerator systems)

• Woo Jun Byeon (PAL)

Room: 5F Grand Hall The Korea-4GSR project is developing a fourth-generation storage ring light source that employs a linear accelerator (LINAC) and a booster ring as injector systems. In the LINAC, electron bunches are produced by a UV laser in the photocathode RF gun and subsequently accelerated to 200 MeV. To achieve this target energy, four accelerating structures are utilized, with a solenoid magnet positioned near the gun to provide initial beam focusing. To ensure efficient beam matching into the booster ring, nine quadrupole magnets are arranged downstream of the first accelerating structure. RF power is delivered by two klystron–modulator systems, each exceeding 70 MW in peak power and independently stabilized through dedicated LLRF–SSA feedback control. The RF power supplied to the gun is further conditioned by a waveguide-based phase shifter, circulator, and attenuator, which are manually adjusted prior to operation and fixed during beam delivery. Detailed system parameters and performance characteristics will be presented. This research was supported in part by the Korean Government(MSIT: Ministry of Science and ICT)

operation status of the CSNS Linac (Working group 1: Accelerator systems)

• Huachang Liu (IHEP)

Room: 5F Grand Hall The China Spallation Neutron Source (CSNS) is a pulsed spallation neutron source based on a high-power proton accelerator. Specifically, it comprises an 80 MeV H⁻ Linac (Linear Accelerator) and a 1.6 GeV Rapid Cycling Synchrotron (RCS), with a designed beam power of 100 kW and a repetition rate of 25 Hz. CSNS officially started operation in 2018 and has since steadily increased its beam power to 170 kW. The accelerator system maintains an average annual beam supply time of over 5,000 hours and an operational efficiency of more than 95%. This report presents the operation status of the CSNS Linac as well as the Linac’s future application plans.

Current status of the J-PARC accelerators (Working group 1: Accelerator systems)

• Yasuhiro Kondo (Japan Atomic Energy Agency)

Room: 5F Grand Hall By 2025, J-PARC has achieved its initial performance goals, realizing 1 MW operation in the RCS, 750 kW fast extraction and 90 kW slow extraction operation in the MR. Furthermore, ongoing developments aim for higher beam intensities — for the RCS toward the second target station of the MLF, and for the MR toward the Hyper-Kamiokande experiment. In addition, for the linac, an upgrade project to double the repetition rate is in progress to realize a proton beam irradiation facility. This presentation reports on the current status and upgrade progress of the J-PARC accelerators.

Challenge to direct observation of structure dynamics in photochemical reactions by using Soft X-ray FEL of PAL-XFEL

• Shinichirou Minemoto (The University of Tokyo)

Room: 5F Grand Hall

Operation Status of KOMAC Linac

• Hyeok-Jung Kwon (Korea Atomic Energy Research Institute)

Room: 5F Grand Hall

Status of PLS-II and PAL-XFEL

• Changbum Kim (Pohang Accelerator Laboratory)

Room: 5F Grand Hall

Oral Poster Room: 5F Grand Hall