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17th Workshop on Shielding Aspects of Accelerators, Targets, and Irradiation Facilities (SATIF-17)
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Asia/Seoul
IBS Science Culture Center, Daejeon, Korea
IBS Science Culture Center, Daejeon, Korea
Expo-ro, 55, Yuseong District, Daejeon, Korea
Description
The 17th Workshop on Shielding Aspects of Accelerators, Targets, and Irradiation Facilities (SATIF-17) will be held at the IBS Science Culture Center of Daejeon, Korea on 20-22 Oct. 2026, and will be hosted jointly by the Institute for Rare Isotope Science (IRIS) and Pohang Accelerator Laboratory (PAL) supported by Nuclear Energy Agency (NEA) and DAEJEON Tourism Organization.
Following the original spirit of the SATIF workshop, main objectives are:
- promoting the information exchange among experts in the field of accelerator shielding and related topics;
- identifying areas where international cooperation can be fruitful;
- creating task forces in order to achieve progress in specific priority areas.
Important Dates
- Workshop Dates : 20-22 October 2026
- Abstract Submission Open : 12 March 2026
- Abstract Deadline :
31 July 202631 August 2026 - Registration Deadline : 20 September 2026
Contact (Homepage)
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1
Registration
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2
Welcome & Opening
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Session 1. Source terms, new accelerator facilities and related topicsConvener: Nam-Suk Jung (Pohang Accelerator Laboratory / POSTECH)
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3
Overview of the Radiation safety on RAON
The heavy ion accelerator consists of an ISOL and an IF system, where the ISOL produces rare isotopes using a 70 MeV proton beam and is configured so that they can be re-accelerated by the IF system. In the IF system, for the stable isotope U-238, the maximum beam energy is 200 MeV/u. Currently, a cyclotron-based ISOL system and a low-energy superconducting accelerator are in operation, and preparations are underway for the high-energy section. The radiation safety device for the accelerator is designed to prevent radiation exposure or contamination spread during the operators’ daily activities and to stop the release of radioactive materials generated by the operation of the heavy ion accelerator. This safety device is designed so that the safety system is configured and operated independently. The safety system consists of personal safety and interlock systems as well as a radiation monitoring system, and the details will be explained in this workshop.
Speaker: INSEOK HONG (IBS) -
4
The Facility for Rare Isotope Beams: Radiation Transport Supporting Power Ramp-Up
The Facility for Rare Isotope Beams (FRIB) serves as the world’s most powerful heavy-ion accelerator. Currently operating at 20 kW, plans are underway to increase beam power by a factor of 20.
In operation since 2022, FRIB produces rare-isotope beams through in-flight fragmentation of high-power beams of stable heavy-ion isotopes ranging from oxygen to uranium at energies up to 200 MeV per nucleon. Besides high power, challenges unique to FRIB compared to most other hadron facilities include its location in an urban public setting and ever-changing beam conditions.
The role of the FRIB Radiation Transport Group is to provide analysis to underpin facility decisions on regulatory compliance and operational efficiency. Examples of recent group work are shown supporting the facility’s progress to higher power including fast estimator tools applicable for constantly-changing beam conditions and validation efforts.This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics and used resources of the Facility for Rare Isotope Beams (FRIB) Operations, which is a DOE Office of Science User Facility under Award Number DE-SC0023633.
Speaker: Juan Zamora (Facility for Rare Isotope Beams) -
5
Shielding Calculations for PETRA IV Beamlines using FLUKA Monte Carlo Code
In recent years, a new fourth generation of light sources has emerged based on advanced storage-ring lattice concepts. This new approach enables a significant reduction in horizontal emittance compared with existing facilities. PETRA III at DESY is one of the brightest synchrotron radiation sources worldwide, serving a broad international and multidisciplinary user community through 25 specialized beamlines operating at a storage-ring energy of 6 GeV and a beam current of 120 mA. The PETRA IV project aims to upgrade the current synchrotron radiation source PETRA III at DESY into an ultra-low-emittance fourth generation of light source.
Within the framework of the PETRA IV project, the new experimental hall PXW, located in the western part of the DESY campus, will host additional PETRA IV beamlines. Radiation shielding calculations have been performed using the FLUKA Monte Carlo code to determine appropriate wall and ceiling thicknesses for the optics and experimental hutches. In addition, FLUKA simulations have been used to evaluate key parameters, such as beam offset in the optics hutch, which significantly influences radiation levels in the optic hutches. This work presents the current status of the PETRA III beamlines and the planned beamlines for PETRA IV, along with selected results from the shielding calculations for PETRA IV hutches, it also includes an investigation of beam-offset estimation for a monochromatic beamline, as well as the challenges and difficulties encountered in shielding design and construction implementationSpeaker: Leila Mokhtari Oranj (DESY) -
10:20 AM
Coffee Break
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6
Swap-Out Safety Analysis Methods for the ALS-U Project
The Advanced Light Source Upgrade (ALS‑U) project at the Lawrence Berkeley National Laboratory (LBNL) requires a comprehensive evaluation of a swap‑out incident, defined as an errant electron beam being injected into a photon beamline and subsequently lost, resulting in potentially unacceptable radiation dose levels on the experimental floor. Historically, for the currently operated ALS facility, this scenario was analyzed through detailed reverse‑tracking accelerator physics simulations to determine the precise locations and apertures of beam masks capable of intercepting mis‑steered electrons inside the accelerator tunnel. While effective, that method demanded extensive knowledge of all lattice elements and required nearly two years of sustained computational effort.
For ALS‑U, a more streamlined and forward‑looking methodology was developed. Consistent with the current ALS safety strategy, the upgraded facility will rely on multiple engineered layers of protection, including beam‑energy and beam‑current interlocks to reduce the probability of occurrence and interlocked radiation monitors to minimize event duration. Additionally, clearing magnets at the entrance of photon beamlines together with photon beam masks will ensure that any errant beam is lost inside the shield walls.
However, because the ALS‑U magnet lattice was still evolving during the safety analysis phase, traditional reverse‑tracking was impractical. Instead, a ray‑tracing–based approach that uses all electron beam trajectories transmitted through the main aperture that separates the electron storage ring from the photon transport line and includes the effect of the clearing magnet field, was implemented to identify the worst possible electron strike locations for a set of representative beamlines, followed by radiation‑transport simulations to quantify dose levels outside the shield walls and verify the existing shielding.
This analysis validates the efficacy of the clearing‑magnet concept, allows to optimize masks aperture and location along a beamline without the need of extensive electron beam reverse tracking, and identifies locations where supplemental shielding is needed.
Together, these results provide a robust technical basis for the ALS‑U swap‑out safety strategy and ensure that the upgraded facility meets stringent radiation‑protection requirements while enabling next‑generation synchrotron performance.Speaker: Stefania Trovati (Lawrence Berkeley National Laboratory) -
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Radiation Protection, Power and Beam Loss Management for the SLAC Linac Coherent Light Source-II High-Energy Upgrade (LCLS-II-HE)
The Linac Coherent Light Source II High-Energy (LCLS-II-HE) upgrade at SLAC extends the superconducting radiofrequency linac from a nominal beam energy of 4 GeV to 8 GeV, doubling available beam power to approximately 240 kW and enabling expanded free-electron laser capability. The higher beam energy produces harder and more forward-peaked electromagnetic showers, which can elevate dose rates at shielding boundaries, penetrations, and outside facility boundary, increase air-activation potential, cause damage to safety devices (beam dumps, stoppers, and collimators), and raise residual-radiation source terms. Meeting radiation-protection goals and operating the facility within the pre-defined safety envelope under these conditions requires an integrated approach that couples engineered access control and beam-limiting functions with updated shielding and instrumentation.
This work summarizes the implementation of the Radiation Safety System (RSS) for LCLS-II-HE, with emphasis on beam loss control and radiation protection for high-power operations. The RSS framework integrates engineered controls through shielding, the Access Control System (ACS), and the Beam Containment System (BCS). The ACS prevents personnel exposure during beam operations by enforcing controlled access states and interlocked entry protections. The BCS limits the radiological consequences of credible beam-loss scenarios through a combination of passive shielding, beam-loss monitoring with interlocked devices, and beam shutoff instrumentation. Major upgrades for LCLS-II-HE include the reevaluation of shielding for 8 GeV beam operation, expansion and reconfiguration of BCS components, and modifications to PPS boundaries and operational modes to support the enhanced accelerator capabilities.
A key component of safe high-power operation is power management using credited BCS devices limiting beam current and energy together with distributed long beam-loss monitoring, with conservative trip thresholds derived from systematic uncertainty tracking and protection-setting methodology. This integrated approach provides bounded operation across normal tuning and abnormal loss conditions, supporting reliable accelerator performance while maintaining protection of workers, users, the public, and the environment.
Keywords: LCLS-II-HE; radiation safety system; access control system; beam containment system; shielding; beam loss monitoring; power management
This work was supported by the United States Department of Energy Contract DE-AC02-76SF00515.
Speaker: Jan Blaha (SLAC National Accelerator Laboratory) -
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Radiological Commissioning of the LCLS-II CW Superconducting Linac: Shielding Validation and Radiation Monitor Performance
The Linac Coherent Light Source II (LCLS-II) at SLAC is a continuous-wave (CW) superconducting radiofrequency (SCRF) electron linac that accelerates electrons to about 4 GeV at MHz repetition rates, with a design beam power of 120 kW and a maximum credible beam power of 1.2 MW. Radiological commissioning advanced through staged beam destinations: halo collimators along the linac, the Beam Switch Yard Dump (BSYD) embedded in the 17 m iron muon shield wall between the linac and the undulators, and the electron beam dumps (EBDs) that follow the soft and hard X-ray undulators. At each stage, prompt and residual dose rates were measured, and passive shielding and active monitoring systems were validated.
All prompt dose rates at occupied service-area penetrations remained below the 5 μSv/h design limit at every beam power commissioned so far, up to about 19 kW. The highest readings stayed about a factor of two below that limit. FLUKA Monte Carlo calculations reproduce the measured prompt and residual fields, in most cases within a factor of two and at several locations within a few tens of percent. This shielding benchmark directly supports the radiation-protection framework for the High-Energy (HE) upgrade to 8 GeV, now being installed.
Beam-loss and radiation monitor commissioning produced several transferable findings. CIVIDEC B4 polycrystalline diamond Point Beam Loss Monitors (PBLMs) exhibited signal decay with an approximately 18-hour half-life after beam-off due to charge trapping, rendering them unsuitable for machine protection; single-crystal B1 replacements respond proportionally and promptly to beam loss with no extended decay. Thick targets attenuate the Cherenkov signal from quartz Long Beam-Loss Monitor (LBLM) fibers by more than an order of magnitude. Oxygen-15 activation of dump cooling water, read by a Residual Dose Monitor (RDM) at the heat exchanger, provides a real-time proxy for the power delivered to the dumps, the onset delay and the decay constant being set by the coolant transit time and by the short-lived activation products. Dark current from SCRF cryomodules produces a persistent radiation background, and characterizing how these fields propagate through the linac tunnel is essential for reliable interpretation of the fixed monitor baselines.Speaker: Thomas Frosio (SLAC) -
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Discussion : Session 1. Source terms, new accelerator facilities and related topics
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3
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Lunch
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Session 3. Code benchmarking and intercomparisonConvener: Toshiya Sanami (KEK)
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Overview and Results of the “Intercomparison” Reported at SATIF
This paper reports on the “Intercomparison” conducted from SATIF-3 through SATIF-16 (excluding SATIF-11).
Unlike “benchmarks,” which are compared with experimental data, “intercomparisons” aim to compare differences among computational codes using identical calculation conditions (such as source, material composition, and conversion factors for dose, etc.). Two types of intercomparison initiatives were conducted within SATIF. Both were “collaborative efforts by SATIF participants” in which participants submitted results obtained using their respective codes in response to “proposed challenges” issued by the organizing committee, and the results of the inter-code comparisons were reported at SATIF.
This presentation will introduce the details of these two types of intercomparisons and the final results obtained.Speaker: Hideo Hirayama (KEK, High Energy Accelerator Research Organization and Nuclear Regulation Authority) -
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The Shielding Integral Benchmark Archive Database (SINBAD) Technical Review Group
The Shielding Integral Benchmark Archive Database (SINBAD) was established in the late 1990’s as a collaborative undertaking between the OECD Nuclear Energy Agency (NEA) and the Oak Ridge National Laboratory (ORNL) Radiation Safety Information Computational Center (RSICC), with the aim to preserve the information on radiation shielding experiments, to answer codes and nuclear data validation needs and to make benchmarks available in a standardised format to the international community. In 2021, the NEA Expert Group on Physics of Reactor Systems (EGPRS) initiated a SINBAD Task Force (TF) gathering shielding experts, experimentalists and benchmark evaluators with the aim to reinvigorate the work on SINBAD and to reactivate its community.
Between 2021 and 2025, the SINBAD TF has successfully steered the development of the database providing new documentation, new maintenance processes and new entries to be evaluated. In 2024, the database migrated to the NEA GitLab server, leading to SINBAD Version 2: a transparent, collaborative, version-controlled, and continuously improved database of 102 entries. In 2024 and 2025, the SINBAD TF approved the first two major additions to the database in ten years: a new evaluation of experimental measurements performed at the Health Physics Research Reactor (HPRR) at ORNL and a complete revision of the pre-existing ORNL Oxygen Broomstick evaluation. Three other existing evaluations also went through minor revisions. These accomplishments demonstrated the new collaborative opportunities offered by the transition to the NEA GitLab server and the updated licences and maintenance processes. With the momentum gained by the Task Force, the NEA Nuclear Science Committee (NSC) decided in 2025 to promote it to a Technical Review Group (TRG). This newly mandated body is composed of 22 delegates representing 11 NEA member countries. The first meeting of
the TRG was held in February 2026 and its first mandate runs until December 2027.The SINBAD TRG mandate now also includes the preservation of numerical intercomparisons to contribute to the international verification effort, as it was suggested by the SATIF-16 participants. The first numerical entry in SINBAD consists of the compilation and analysis of intercomparison exercises developed through the successive SATIF meetings. The report, still under review, focuses on three major intercomparison exercises in iron and concrete shields: attenuation of medium and high energy neutrons, dose caused by medium energy neutrons and neutron energy spectra comparison.
During its meeting in February, the SINBAD TRG proposed several new potential entries, including an evaluation of measurements reported by the Japan Atomic Energy Research Institute (JAERI) of induced radioactivity from a mercury target irradiated at the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory (BNL) using a 24/2.83 GeV proton beam. Other proposals included evaluations of zirconium and oxygen broomsticks neutron transmission experiments, evaluations of 238U neutron transmission experiments and a numerical intercomparison derived from a simplified alarm placement benchmark from the International Criticality Safety Benchmark Evaluation Project (ICSBEP).A subgroup to develop machine-readable data formats for SINBAD was also proposed. This follows the overall data management strategy of the NSC and its adaption to recent changes in the way data is consumed. Experts and data users specifically express needs for machine-readable data, standardised data formats and application programming interfaces (APIs), while maintaining state-of-the-art quality assurance for the data. The goal of the subgroup is to propose a pilot machine-readable entry from the SINBAD database, accompanied with wellspecified data formats. These formats will be designed in conjunction with the subgroups supervising similar efforts in other NSC databases.
The presentation will provide an overview of the above-mentioned accomplishments made by the SINBAD Task Force and objectives of the new SINBAD Technical Review Group.
Speaker: Davide Mancusi (OECD/NEA) -
12
Nuclear Data Sensitivity and Uncertainty Analysis of the TIARA Fe and Concrete Shielding Benchmark from the SINBAD Database
Shielding Integral Benchmark Archive and Database (SINBAD) [1] includes over 100 shielding benchmarks covering fission, fusion and accelerator applications. The project started in the early 1990-ies at OECD/NEA Data Bank and RSICC with the objective to preserve the experimental data and the information on the measurement procedure. SINBAD provides an experimental database for the integral validation and improvement of basic nuclear data and computer codes. The analysis of benchmarks helps identifying nuclear data status and needs where future nuclear data evaluation and experimental activities should focus,
23 accelerator benchmark experiments involving both neutrons and gamma-rays are included with shielding materials such as Fe/stainless steel, Cu, W, O, concrete and many more. Many more benchmarks are waiting in the “to-do” list since many years, since the progress in benchmark evaluations is practically at the stillstand since over a decade. Better times seem to be ahead with the SINBAD Task Force slowly starting adding new entries. While the 2012 SATIF presentation [2] still describes well enough the present status of the database, the new organisational framework should act as an invitation to accelerator community to consider contribution experimental data to SINBAD again.
An analysis of TIARA benchmark, included in SINBAD using both Monte Carlo and deterministic codes will be presented. The combined use of both methods allowed to spot some differences and inconsistences in the modern nuclear data evaluations, such as FENDL-3.2, JEFF-4.0 and ENDF/B-VIII.1. Moreover, the transport calculations were complemented by the sensitivity and uncertainty (S/U) calculations to identify the most sensitive isotopes and nuclear reactions, and to evaluate the computational uncertainties due to nuclear data uncertainties.
S/U analysis of a recent IFMIF-DONES concrete benchmark performed at the Rez facility will be presented. This concrete benchmark represents a good potential candidate for future SINBAD evaluation.
REFERENCES
[1] I. KODELI, E. SARTORI, SINBAD – Radiation shielding benchmark experiments, Annals of Nuclear Energy 159 (2021) 108254.
[2] I. Kodeli, P. Ortego, R.E. Grove, A. Yamaji, Current Status of Accelerator Benchmarks in OECD/NEA Radiation Shielding Experiments Database SINBAD, Workshop Proceedings "Shielding Aspects of Accelerators, Targets and Irradiation Facilities - SATIF-11", Tsukuba, Japan 11-13 September 2012, NEA No. 7157, OECD 2013Speaker: Ivan Alexander Kodeli (UKAEA) -
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Benchmark and applications of the Mesh-Enabled Fluence Weighting tool for Radiation Protection studies for the LHC experiments
Upgrades to the CERN Large Hadron Collider (LHC) and its experiments began on 29 June 2026 and are expected to last until 2030. During this time, the four large LHC experiments will be modified to withstand the higher collision rates and irradiation conditions of the new High-Luminosity LHC (HL-LHC). Dismantling and decommissioning of activated detector components will be followed by the installation of new detectors and electronics. A significant quantity of radioactive material will be removed from the radiation areas, and the evacuated material must undergo detailed radiological characterisation to determine the most appropriate disposal paths.
The CERN RP group typically uses the FLUKA Monte Carlo code to support radiation safety assessments and calculation of various operational radiation protection quantities. The Mesh-Enabled Fluence Weighting (MEFW) tool was developed to improve efficiency by building on FLUKA’s existing capabilities.
This paper summarises the results of a benchmark of Monte Carlo simulation predictions for the Compact Muon Solenoid (CMS) experiment. Thirty-eight samples representing three commonly used materials in accelerator and detector components were installed in various locations of the cavern and left in position for several months of beam irradiation. The samples were then analysed by means of gamma spectrometry with High Purity Germanium (HPGe) detectors. Benchmark simulations were performed with the FLUKA code and the MEFW tool.
The tool can be applied more broadly, as material composition, irradiation history, and cooling time are all defined at the post-processing stage, allowing a single simulation dataset to support multiple independent studies. As an example, the MEFW tool was used to classify LHCb detector components removed in 2018. Calculated quantities that will be presented include material activation, RADOS RTM 661/440 lnc detector response, total detectable gamma-ray signal, and the minimum object mass required for classification by RADOS measurement.
Overall, the tool supports rapid pre-assessment of clearance measurements and helps identify regions where further measurements may be required.
Speaker: Bartosz IDZIOR (KIT/CERN) -
2:40 PM
Coffee Break
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14
Assessing stray neutron dose variability across Monte Carlo codes in a proton therapy scenario
Monte Carlo (MC) simulations are widely used for dosimetry in proton therapy, yet substantial differences in neutron dose estimates persist between simulation codes due to variations in nuclear interaction models and cross-section libraries. To quantify these differences, a collaborative study by EURADOS Working Groups 6, 9, and 11 compared neutron fluence and dose equivalent calculations using five widely employed MC codes (PHITS, MCNP, FLUKA, GATE, and TOPAS).
A clinically relevant spread-out Bragg peak proton beam was simulated in a reference water phantom. Neutron fluence spectra and dose equivalents were evaluated at several out-of-field locations using each code's default physics models and nuclear data libraries. The influence of alternative proton and neutron cross-section libraries and different nuclear models was also investigated.
All codes reproduced the proton dose distribution consistently, with spatial differences below 2 mm. In contrast, neutron fluence varied by up to 130%, while neutron dose equivalent differed by as much as 88%, depending on the selected nuclear data. Variations in proton interaction cross-sections had a greater impact on neutron production than differences in neutron cross-sections. Simulations employing the same nuclear data libraries showed good agreement across codes, identifying the choice of nuclear data as the dominant source of variability.
Speaker: Dávid Horváth (ELI ERIC) -
15
Benchmark activation experiment of various foil samples using the ESS accelerator dump line
A set of tools for fast and reliable activation calculations is being studied and developed at the European Spallation Source (ESS). These consist of classic radiation transport codes, and more novel and rapid solutions, involving machine learning techniques for activation estimations. This set of tools will provide support for operations and radioactive waste classification and management.
As part of the validation effort proposed, an experiment was conducted at ESS, using the Proton Beam Imaging device (PBI) in the Beam Dump line of the linear accelerator as an irradiation facility for six foil samples, made of Al, Cu, Fe, Ni, Nb and Bi. The samples were positioned on top of the component, which contains an Aluminum Oxide screen that acts as a spallation target. After an irradiation, the gamma spectra emitted by the samples was measured using Canberra Mirion HPGe detectors, and activation at the end of irradiations for present nuclides was extracted from the measurements and using the Genie2k software.
The experimental conditions were replicated using PHITS 3.35, with the source term for the irradiations extracted from the imaging device measurements. Activation calculations were performed using DCHAIN, and activity from the experimentally identified nuclides was compared to computational results.Speaker: Tomás Dähn Costante (European Spallation Source ERIC) -
16
Monte Carlo Benchmarking of Concrete Activation Induced by 9.7 GeV Electrons at PAL-XFEL
Concrete activation has been investigated at several accelerator facilities, including Pohang Light Source (PLS) with 2.5 GeV electrons. To extend the experimental benchmark database to a higher-energy electron beam dump environment, concrete activation experiments were conducted at the Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL-XFEL). A thick copper target (Ø 10.2 × 25.35 cm2, 17.65 X0) was installed in the HX main beam dump bunker, and concrete samples from PAL accelerator facilities were placed on both the left and right sides of the target. A 9.7 GeV electron beam with a beam power of 106 W irradiated the copper target for about 72 hours.
Each concrete sample was measured using an HPGe detector, and the activity concentrations [Bq/g] at the end of the irradiation were determined. The experimental setup was also simulated in detail in PHITS-3.35 and FLUKA 4-5.1. The elemental compositions of the concrete samples, including trace elements, were obtained by elemental composition analysis and incorporated into the Monte Carlo (MC) material definitions as mass fractions. The induced activity concentration of the concrete was calculated considering the irradiation profile.
The neutron and photon fluences in samples were calculated in MC codes, and the activity concentrations for 13 radionuclides were compared between measurements and calculations. The neutron fluences predicted by the two codes were similar, whereas their high-energy photon fluences differed by less than a factor of two. For example, for Co-57, which is dominantly produced by photonuclear reactions, the calculated activities differed substantially between the two codes and showed particularly large discrepancies with the measurements. For other radionuclides, including those predominantly produced by thermal neutron capture reactions, the two codes produced comparable predictions, while the discrepancies between calculated and measured activity concentrations ranged from factors of approximately two to four. Further detailed comparisons between calculated and measured activity concentrations will be discussed.Speaker: Euna Lee (Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea) -
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Discussion : Session 3. Code benchmarking and intercomparison
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10
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4:10 PM
Coffee Break
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Session 5. Induced radioactivity and decommissioningConvener: Anna Ferrari (Helmholtz-Zentrum Dresden-Rossendorf (HZDR))
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18
Development of Survey-based Clearance Methods for the Decommissioning of Cyclotron Yoke Steel
Recently, many cyclotrons used for the production of [F-18] FDG in Korea is in the phase of dismantling. While many studies, such as the assessment of activation levels, have been conducted for cyclotron decommissioning, the research on survey-based clearance method has not been carried out domestically. Therefore, this study aims to discuss the feasibility of developing a survey-based method for Yoke steel of the self-shielded RDS Eclipse cyclotron, which has been out of operation for 9 years.
Since the Yoke steel of the cyclotron are bulky, they are suitable for applying survey-based clearance methods. A FHZ512 BGO(1.5 x 1.5-inch BGO) and FHZ512A(1.5 x 1.5-inch NaI(Tl)) scintillation-based rate meter, which have high detection efficiency, were considered as measurement equipment. First, detection limits according to ISO 11929-1 were obtained through background measurements for each detector. When the measurement time for the background and the Yoke steel was set to 60 seconds, the detection limits for the BGO detector and the NaI(Tl) detector were found to be 9 cps and 7.7 cps, respectively. Using the FLUKA 4-5.2 code, information on radionuclides of interest within Yoke steel was obtained through cyclotron activation calculations that reflected operational history. Subsequently, the expected count rate when measuring Yoke steel with scintillation-based rate meter was obtained using the FLUKA code, and if the count rate is greater than the detection limit, it is evaluated that survey-based clearance method is feasible. Based on results of FLUKA code calculation and field measurement at the cyclotron facility, it was found that it is reasonable to set the radionuclide of interest to a single nuclide, Co-60, rather than multiple nuclides, and that survey-based clearance method can be sufficiently applied to Yoke steel even considering the short measurement time.Speaker: Nam-Suk Jung (Pohang Accelerator Laboratory / POSTECH) -
19
Tritium Production and Release in Particle Accelerator Environments: From Calculations to Experiments
Tritium production in particle accelerator facilities must be carefully evaluated to ensure safe operation and compliance with regulatory limits. Radiation transport codes can estimate tritium production in accelerator components and shielding; however, they generally do not describe the subsequent release of tritium or its diffusion through shielding materials.
This work presents an integrated approach that combines radiation transport calculations with experimental measurements. The Monte-Carlo codes CERN-FLUKA and PHITS are used to design and optimize the planned experimental setup in which various materials are irradiated by secondary particles generated from proton beam interaction with a target. These irradiated materials would then be submerged in water for a specified period, after which the tritium concentration in the water would be measured. These experimental results will provide estimates of tritium release from irradiated materials and support the development of improved models for tritium transport, as well as environmental release in accelerator facilities; this will help expand the tools available for tritium management and safety assessment in the accelerator community.Speaker: Dali Georgobiani (Fermilab) -
20
Residual Dose Rates Measured vs Calculated during Inner Reflector Plug 2 Exchange at SNS
The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) is an accelerator-based neutron source facility that provides the most intense pulsed neutron beams in the world for scientific research and industrial development. SNS converts a 1.8 MW proton beam of 1.3 GeV energy and sub-micro-second pulse width incident on a mercury target into a neutron source at 60 Hz repetition rate. The neutron production occurs when a horizontally injected proton beam strikes the liquid mercury target contained by vessel, which is placed in the center of the target monolith.
The central components of the SNS target monolith are the Proton Beam Window (PBW), the Inner Reflector Plug (IRP), and the target vessel. During operation, these components are exposed to intense radiation fields and therefore become highly radioactive. The incoming proton beam passes through the PBW before striking the liquid-mercury target vessel, which is located within the IRP.
The IRP is replaced on regular basis because neutron poisons in certain moderators gradually burn out, reducing their ability to produce the narrow neutron pulses required for neutron-scattering applications. The replacement of IRP is a complex task due to its location in the area receiving high irradiation, being under significant amount of shielding, and its size requiring removal in segments. For planning the replacement workflow to help to reduce radiation exposure to workers dose rates for each stage of extraction/replacement operation are predicted. Residual dose rates are evaluated through detailed analyses using the MCNP particle-transport code and the Cinder2009 transmutation code. While the replacement was taking place, measurements were performed and later were compared to the calculations.Speaker: Irina Popova (Oak Ridge national Laboratory) -
21
Radiation protection studies and operational experience from the decommissioning of the CNGS target area
The CERN Neutrino to Gran Sasso (CNGS) facility was commissioned in 2006 and operated from 2008 to 2012. It was designed to observe muon to tau neutrino oscillations with an intense muon-neutrino beam generated on the CERN side and directed over 732 km toward the Gran Sasso National Laboratory in Italy. 400 GeV/c protons were extracted from the CERN SPS and interacted with a carbon target, producing pions and kaons that subsequently decayed into muons and neutrinos. The CNGS facility accumulated a total of 1.8 × 10²⁰ protons on target with an average beam power of 510 kW.
The primary motivation for decommissioning the CNGS target area is to reduce the amount of radioactive material requiring long-term on-site storage at CERN. Additionally, decommissioning irradiated target areas allows future projects or experiments to re-use these areas. A specific motivation is the extension of the AWAKE facility, designed to study an innovative particle acceleration method based on proton-driven plasma wakefields. The CNGS target area is in a 100-m-long cavern, located 60 m below ground. It contains around 600 m³ of items to be removed: beamline elements, shielding blocks, supports, ventilation ducts, cables, and other small components.
This study details the radiation protection aspects of the ongoing decommissioning of the CNGS target area planned for completion in 2026. It covers the preparation phase, including FLUKA estimates of the residual dose rates and radionuclide inventories of the main components. It also presents benchmark comparisons between FLUKA simulations and measurements performed during the decommissioning phase. Finally, operational aspects and challenges encountered during the project are discussed, providing valuable feedback for future decommissioning campaigns.
Speaker: Arnaud Devienne (CERN) -
22
Discussion : Session 5a. Induced radioactivity and decommissioning
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Session 4. Shielding and DosimetryConvener: Stefania Trovati (Lawrence Berkeley National Laboratory)
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23
Beam-Loss and Shielding Evaluation Based on Neutron Dosimetry in the NanoTerasu Storage Ring
Introduction
NanoTerasu is a fourth-generation synchrotron light source consisting of a 3-GeV linear accelerator and a storage ring with a circumference of 349 m. The spatial distribution of secondary neutrons generated by electron beam losses contains information on the locations and intensities of beam losses, and is therefore important for shielding design and radiation protection. In this study, the neutron dose distribution in the storage-ring tunnel was measured to identify beam-loss locations. Based on the measured distribution, the beam lifetime was evaluated, and the relationship between neutron doses inside and outside the tunnel was investigated.
Methods
To measure the neutron dose distribution around the entire 349-m circumference of the storage ring, approximately 100 passive dosimeters (Nagase Landauer Luminescence Badges) were installed on the inner wall of the storage-ring tunnel at intervals of approximately 3 m. The dosimeters measured neutron doses during an operating period of 290 h with an average stored beam current of approximately 190 mA. Localized beam-loss locations were identified from peaks in the measured neutron dose distribution.
Results
Localized neutron dose-rate peaks of 4.5 μSv/h and 5.9 μSv/h were observed near the injection section and in one of the storage-ring cells, respectively. Residual radioactivity was also detected at the latter location, suggesting the presence of localized beam loss. Outside the tunnel, neutron doses were below the detection limit at most measurement points. However, at locations corresponding to relatively high neutron dose rates inside the tunnel, neutron doses exceeding the detection limit were also observed outside the tunnel. These results indicate that localized beam losses contribute to the radiation field outside the tunnel after transmission through the shielding structure.
Furthermore, the beam lifetime determined by the identified localized beam loss was estimated to be approximately 64 h, while that associated with Touschek scattering and residual-gas scattering was approximately 13 h. Combining these loss mechanisms yielded an overall beam lifetime of approximately 11 h, which was in good agreement with the beam lifetime determined from the measured decay of the stored beam current.Conclusions
Neutron dose mapping enabled the identification of localized beam-loss locations and their relative intensities in the NanoTerasu storage ring. Increased neutron doses outside the tunnel were observed at positions where relatively high dose rates were observed inside the tunnel, demonstrating a correlation between localized beam losses and the external radiation field. These results are useful for identifying beam-loss hotspots and for assessing shielding measures. In addition, the beam lifetime evaluated from the neutron dose distribution was consistent with that derived from operational data, demonstrating that this method is effective for both beam-loss evaluation and radiation-field assessment.
Speaker: Akihiro Takeuchi (National Institutes for Quantum Science and Technology) -
24
Gas Bremsstrahlung Measurements for Benchmarking PHITS Simulations at NanoTerasu
NanoTerasu is a 3-GeV synchrotron radiation facility in Japan that has been routinely operated at the design beam current of 400 mA since November 2025. In electron storage rings, gas bremsstrahlung produced by interactions between stored electrons and residual gas molecules is unavoidable, and thus shielding against both high-energy photons and photoneutrons is essential. The shielding design of NanoTerasu was evaluated using analytical calculations based on residual gas composition and PHITS Monte Carlo simulations. To validate these calculations and benchmark PHITS simulations, we performed the first direct measurements of gas bremsstrahlung at NanoTerasu.
We installed a $3\times3$ array of CsI(Tl) scintillation detectors ($5\times5\times30$ cm$^3$ each) to capture the lateral development of electromagnetic showers induced by gas bremsstrahlung downstream of a long straight section of the storage ring. Plastic scintillators were additionally used for charged-particle discrimination, and a lead absorber with selectable thicknesses was placed in front of the detector array to suppress low-energy photons. Charge signals from the CsI detectors were recorded using a mesytec MDPP-16-QDC digitizer during routine beam operation periods.
Reliable energy calibration from the MeV to GeV region was achieved using $^{60}$Co and $^{137}$Cs $ \gamma$-ray sources, environmental radiation peaks, and energy-deposition peaks of cosmic-ray muons [1]. Energy-calibrated gas-bremsstrahlung spectra were compared with PHITS calculations of energy deposits in the CsI detectors. The presentation will discuss the measurement and calibration procedures, and a systematic comparison between measured and simulated spectra under various lead-shielding conditions. These measurements are expected to establish a basis for future quantitative validation of gas-bremsstrahlung simulations and the associated shielding design at NanoTerasu.
[1] Hayakawa et al., “Energy Calibration of CsI(Tl) Scintillation Detectors for Gas Bremsstrahlung Measurement at NanoTerasu”, Proceedings of the 40th Workshop on Radiation Detectors and Their Uses, KEK Proceedings 2026-3, 108-120 (2026).
Speaker: Seiya Hayakawa (National Institutes for Quantum Science and Technology) -
25
Comparison of CR-39 Personal Neutron Dosimeter Measurements and PHITS Calculations in a 24 GeV/c Proton-Induced Radiation Field
In high-energy accelerator facilities, severe radiation exposure may occur in accidental scenarios, such as personnel being inadvertently left inside an accelerator tunnel during beam operation or unexpected beam delivery. Personal dosimeters may provide essential information for estimating the received dose after such events. However, the reliability of dose assessment using personal neutron dosimeters under extremely high-dose and high-energy mixed radiation fields has not yet been fully established.
Monte Carlo simulations have been widely used to evaluate complex high-energy radiation fields in accelerator facilities. Nakao et al. measured high-energy neutron streaming through an access maze at the CERN High-energy AcceleRator Mixed-field (CHARM) facility using activation detectors and showed that Monte Carlo simulations can reasonably reproduce the measured radiation field [1]. In the present study, PHITS simulations were used to calculate neutron dose values for comparison with CR-39 measurements.
An irradiation experiment with CR-39 personal neutron dosimeters was conducted in the access maze of the CERN/CHARM. The neutron doses evaluated from the CR-39 dosimeters were compared with the calculated neutron dose values. In the typical neutron response energy range of CR-39, from 25 keV to 15 MeV, the measured and calculated doses agreed within a factor of 1.9. When the comparison was extended to a wider neutron energy range from 0.025 eV to 1 GeV, the agreement remained within a factor of 2.5.
In addition to the dose comparison, microscope images of the chemically etched CR-39 detectors were further analyzed to investigate track features possibly related to high-energy neutron interactions. Pit candidates were extracted using a simplified image analysis method based on size and shape features. Multi-charged-particle candidates relevant to observable etched pits were selected from PHITS T-Product dump data by combining particle type, energy, emission direction, and generation position with SRIM-based LET and stopping range in CR-39. The PHITS results indicated that such candidates were mainly associated with neutrons above approximately 10 MeV.
Some observed multi-pit clusters showed spatial patterns similar to the multi-charged-particle topologies predicted by PHITS. These results suggest that topology-based information from CR-39 microscope images may complement conventional track-count-based dose evaluation and help interpret observed track features in relation to high-energy neutron-induced charged-particle production predicted by Monte Carlo simulations.
[1] Measurements and Monte Carlo simulations of high-energy neutron streaming through the access maze using activation detectors at 24 GeV/c proton beam facility of CERN/CHARM, N. Noriaki, et al., J Nucl Sci Technol. 2021;58(8):899–907.
Speaker: Eunji Lee (KEK/J-PARC) -
26
Discussion : Session 4a. Shielding and Dosimetry
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Session 2. Code status, development and model convertersConvener: Hee-Seock Lee (Pohang Accelerator Laboratory, POSTECH, South Korea)
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Multiphysics, seven incident particles nuclear data libraries generation: TENDL-2025
The multipurpose, Multiphysics nuclear data libraries generated by TALYS-2.2 & neutron resonance databases, TEFAL, TASMAN as the Evaluated Nuclear Data Library TENDL has now been released every other year recently. Considerable experience has been acquired during the production years of global repetitive seven incident particles (neutron, proton, deuteron, triton, alpha, helium and gamma induced) multipurpose, application agnostic nuclear data libraries with covariance information up to 200 MeV incident energy on about 2850 (T½ > 1s) targets Z=3 6Li to Z=115 291Mc. The library information is stored in the ENDF-6, GNDS-2.0 data formats explicitly below 30 MeV, implicitly above. The backbone of this achievement is completeness, quality, upgradability and, most of all, reproducibility and methodology. Since, TENDL has been comprehensively embraced by many, quite different applications (accelerator, astrophysics, fusion, fission, medical, experimental, decommissioning, etc.) that require multifaceted nuclear structure, reaction data in various forms, primary and derived, for not only criticality but shielding, transport, radioprotection, inventory (daughters T½ > 0.1s), experimental interpretation, materials or earth sciences. The essential knowledge is not the TENDL libraries themselves, but rather the necessary physics models, databases and methods, processes, scripts, codes, tools and know-how that go into the making of every evaluation of the libraries. Recent efforts have focused on better assessment of the underlying physics reproductible open-source models coding, default’s nuclear structure data, charge particles related parameters, the incorporation of updated databases information and metrics into the scientific framework workflow. The codes are hosted at the IAEA nuclear data section GitHub while the bulkier libraries, in original formats and many application forms, are now available from Imperial College London servers.
Industry recognized traditional nuclear data libraries (JEFF-OECD, JENDL-Japan, ENDF/B-US, CENDL-China) have, are being assembled over decades by hand, evaluator’s added nuclides/reactions/energies as and when it was deemed necessary for principally fission, low energy, neutron-based applications. The methodology is robust when high-quality, differential and integral experimental data are available and can be successfully embedded in their making; however relative to the total set of target nuclides/reactions/energies/daughters and derived data needed for the many other applications such as accelerator shielding, these libraries are restricted and incomplete. They generally do not contain any more than a very small fraction of the target, data, forms and observables needed for other non-operational fission, non-criticality applications: non-elastic double differential data, branching ratio, radionuclides daughters’ production, gas, emitted particles and residual recoil spectra, etc. Since many (or most) reactions important for advanced; shielding, accelerators, fusion, instrumentation and manufacturing, security or astrophysics systems have few, scattered or no experimental differential information, one cannot rely on these traditional libraries, and a robust model alternative is necessary to explore the broader nuclear application landscapes. TENDL-2025 fills the space between on-the-fly high energy collision models and low energy tables, leads the way scientifically and technologically into chartered and uncharted territory. Machine Learning and Artificial Intelligence processes are being deployed on the scientific framework workflow. The use of TALYS as an advanced single energy event generator is also proposed.
https://tendl.imperial.ac.uk
https://www-nds.iaea.org/talys/Speaker: jean-christophe sublet -
28
Recent Developments of the Serpent Monte Carlo Code
Serpent is a multi-purpose, three-dimensional, continuous-energy Monte Carlo neutron and photon transport code developed at VTT Technical Research Centre of Finland. Originally established in reactor physics and criticality safety, its scope has broadened considerably in recent years toward applications of direct interest to the SATIF community, including radiation shielding and damage, dosimetry and detector modelling, and fusion neutronics.
Recent developments include new physics and radiation-source sampling models, improved energy-deposition and damage estimates, and extended particle-cascade transport capabilities, supported by new methodologies and libraries in nuclear data handling that extend to transport and activation/transmutation calculations.
New variance-reduction techniques, hybrid tallying schemes, advanced detectors, source characterization methods, and sensitivity and uncertainty quantification capabilities are complemented by broader geometry support and interfaces for coupling with other transport and multi-physics codes, some of which are now part of VTT's Kraken framework, extending Serpent's applicability to complex, realistic problems relevant to shielding and dosimetry applications.
As this application space has grown, so has the emphasis on verification, validation, and quality assurance: Serpent's development and release process now relies on a structured V&V program aligned with NQA-1 and ISO 9001, reflecting its increasing use in contexts where qualification and traceability of results are required.
Speaker: Ana Jambrina (VTT Technical Research Centre of Finland Ltd)
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10:35 AM
Coffee Break
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Session 2. Code status, development and model convertersConvener: Hee-Seock Lee (Pohang Accelerator Laboratory, POSTECH, South Korea)
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MARS code developments and applications to DUNE/LBNF, PIP-II and Mu2E projects
Major features of the most recent version of the MARS code as well as ongoing developments are described. The latter include the following: (i) a new geometry module based on SDF (Signed Distance Field) surface representation; (ii) transitioning from an outdated representation of
output data; (iii) refactoring of the code and removal of obsolete Fortran features; (iv) adaptation to execution in a distributed computing environment. Applications of the code to major projects at Fermilab−DUNE/LBNF, PIP-II, and Mu2E−are described as well.Speaker: Igor Rakhno (Fermi National Accelerator Laboratory) -
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FLUKA: status and recent developments
See the abstract in attachment
Speaker: Anna Ferrari (Helmholtz-Zentrum Dresden-Rossendorf (HZDR)) -
31
FLUKA new developments towards the 5th code generation
FLUKA users are already benefiting from a steady stream of physics and technical improvements delivered through the current production code. After native support for unstructured meshes made available in v4-5, the upcoming major release v4-6 improves isomer production, enables direct use of PENDF neutron databases, introduces X-ray reflection at boundaries, and provides a refined fission model. Point-wise neutronics has been substantially enhanced, with better treatment of unresolved-resonance cross sections, Doppler broadening corrections, exotic reaction channels, and ab-initio thermal-scattering law handling for crystalline and molecular materials. Each release is subject to an elaborate, multi-layered validation campaign — combining continuous integration testing, dedicated feature test suites, and the FLUKAVAL framework of reference test cases with automated execution and analysis — ensuring that new physics and technical developments are thoroughly vetted before reaching users. These advances translate directly into more accurate and reliable simulations for radiation protection, accelerator design, medical physics, and space applications, without requiring users to change their existing workflows.
Looking ahead, the 5th generation of FLUKA is undergoing its most significant evolution to date: a full re-architecture built on top of the Geant4 toolkit and a modern geometry engine, designed to combine FLUKA's physics performance with the flexibility, extensibility, and interoperability of a widely adopted simulation framework. This next generation will bring seamless mixed-geometry modeling, improved medical imaging workflows, and refined treatments of ionization and multiple scattering. A modernized nuclear database will improve the accuracy and consistency of decay, transition, and level data across simulations.
Complementing this transition, new AI-assisted tools are emerging to support users and developers alike — from automated input creation and code documentation to intelligent assistance embedded directly in the Flair graphical interface — easing the path for the community as it will migrate to FLUKA v5.
Flair continues to serve as the shared GUI and geometry backbone across this evolution, now supporting FLUKA v4 & v5, PHITS, MCNP, and (partially) OpenMC, with on-the-fly cross-code input conversion as well as expanded lattice and torus support. A newly refined geometry engine delivers a ten-fold performance increase for geometries using parentheses, bringing their tracking speed on par with manually optimized, expanded geometries. Since FLUKA v5 builds directly on the flair geometry kernel, it inherits these performance gains immediately, showcasing how improvements to the shared infrastructure benefit both generations of the code at once.
Speaker: Vasilis Vlachoudis (CERN) -
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Unstructured Mesh geometries in FLUKA: Recent Developments and Applications
Support for CAD-based geometries through conversion into Unstructured Mesh (UM) elements was introduced as of FLUKA v4-5.0, strongly enhancing the workflow between engineering design and radiation transport simulations, as well as allowing for the use of state-of-the-art anthropomorphic mesh phantoms.
FLUKA’s optimized implementation, utilizing the capabilities of Flair’s geoviewer kernel, enables the import of CAD-derived UMs composed of tetrahedral, pentahedral, or hexahedral elements, while supporting different mesh formats. Complex engineered geometries can now be constructed by concatenating multiple UMs and combining them with conventional constructive-solid-geometry bodies and lattice elements for periodic structures. To further facilitate interplay between FLUKA and engineering software and to extend the use of UM geometries for internal dosimetry studies, the implementation supports scoring within individual UM elements and uniform particle sampling in UM-defined regions.
The upgraded capabilities of FLUKA are demonstrated by two representative applications. The first exploits the support of UMs to implement the ICRP 145 mesh phantoms into FLUKA and calculate a consistent set of particle-fluence-to-effective-dose conversion coefficients. The second application demonstrates the assembly of an accelerator beam line geometry in FLUKA, where individual components represented by UMs are combined using the recently released LineBuilder (LB) tool.
Speaker: Giuseppe Mazzola -
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AI-Agent-Assisted Shielding Calculations: Implementation of PHITS Workflows and Prospects for Multi-Code Monte Carlo Simulations
Monte Carlo particle transport codes are essential tools for accelerator shielding design, radiation safety assessment, and dose evaluation. However, their practical use requires detailed knowledge of input syntax, geometry modeling, source definition, tally selection, statistical uncertainty evaluation, and output interpretation. Recent progress in large language models and AI agents may provide a new way to support such complex workflows.
In this presentation, we introduce AI-assisted workflows developed for PHITS as a practical example. An AI-readable knowledge base was prepared from PHITS manuals, lecture materials, recommended inputs, sample files, utility information, and developer-curated cautions. This knowledge base was used for conversational PHITS support with NotebookLM and for AI-agent-driven execution and analysis workflows using agents such as Codex and Claude Code. Demonstration tasks showed that AI agents could edit PHITS input files, execute calculations, inspect errors, perform post-processing, and assist with shielding optimization when appropriate knowledge resources and operational rules were provided.
Based on these results, we would like to discuss at the meeting the future role of AI agents in shielding calculations, particularly their potential to execute multiple Monte Carlo codes under comparable conditions, support benchmarking and intercomparison, and help users focus on physical interpretation, uncertainty assessment, and engineering judgment.Speaker: Tatsuhiko Sato (Japan Atomic Energy Agency) -
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Discussion : Session 2. Code status, development and model converters
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Lunch
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2:00 PM
Technical Tour Rare isotope Accelerator complex for ON-line experiments, Daejeon, Korea
Rare isotope Accelerator complex for ON-line experiments, Daejeon, Korea
Gukjegwahak-ro 1, Yuseong District, Daejeon, Korea -
Poster SessionConvener: INSEOK HONG (IBS)
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Residual Dose Assessment of High-Activity Water at the TRIUMF ARIEL Proton Target Station
High-activity water (HAW) generated during proton-beam operation represents an important source of residual radiation at high-power accelerator facilities. At the TRIUMF ARIEL proton target station, activated cooling water associated with the beam dump and medical-target components can contribute to radiation fields in the Target Preparation and Service Room (TPSR) and adjacent accessible areas. This work presents a FLUKA-based assessment of the residual dose rates arising from activated water and investigates shielding configurations to maintain acceptable radiation levels in the neighbouring Hot Cell Ante Room. The activation and subsequent transport of radiation from the HAW package were simulated using a detailed model of the ARIEL target station and surrounding areas. A conservative short cooling time was considered to assess the radiation field shortly after beam operation. Different shielding concepts for the TPSR entrance were investigated, including a concrete maze and a shielded-door configuration. The calculations indicate that radiation streaming through the entrance can lead to elevated dose rates in the adjacent area when using the concrete-maze configuration, whereas the introduction of additional shielding substantially reduces the radiation field outside the TPSR.
Speaker: Marco Hartmann (TRIUMF) -
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Linking shielding calculation and BIM for accelerator facility design
When an accelerator facility is constructed, an architectural drawing is written based on shielding calculation results. Although shielding calculation and architectural design work separately, communication in design process between them is important to build a reasonable and easy-to-use accelerator facility. If communication is poor, the facility may be inconvenient layout which is a particular problem in medical accelerator facilities.
In order to facilitate the communication, a development is carried out to link the shielding calculation result and BIM that has been used in the design. BIM (Building Information Modeling) is a system that improves the efficiency of facility design and construction by inputting various information, such as building material information, into a 3D building model. We created a program to display the shielding calculation results of PHITS and DCHAIN on the BIM. This software can read PHITS and DCHAIN output files, convert them to a format that BIM software can read, and display them in a BIM model.
By linking BIM with shielding calculation results, it is possible to display 3D distributions of dose and activity. Communication between shielding calculations and architectural design become smoother, this allows to improve the efficiency of design work such as room layouts.Speaker: Koichi Okuno (Hazama-Ando Corporation) -
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Preliminary Evaluation of the G-Value for Ozone Production in Air under Synchrotron White-Beam Irradiation
Ozone can be produced when synchrotron white beams interact with air, but reported G-values vary with irradiation conditions and experimental configuration. In this preliminary study, ozone production was measured in a sealed air chamber using a bending-magnet white beam at four opening angles (0.177-0.5 mrad). The absorbed energy in air was calculated from the white-beam spectrum and air energy-absorption data. The G-value was calculated using the absorbed energy in air and the ozone concentration estimated at beam-off. The resulting values ranged from 1.252 to 1.744 molecules/100 eV, with a mean of 1.520 ± 0.207. The measurements were limited by the 0.5 ppm upper range of the ozone monitor, requiring irradiation to be restricted to 5 s. Further experiments using a wider-range UV absorption ozone monitor and additional white-beam conditions and beamlines are planned to refine the G-value evaluation and support ozone assessment in synchrotron beamline environments.
Speaker: Jonghun Jang (POSTECH PAL) -
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Measurement of Magnetic Field Variation in NdFeB and SmCo Permanent Magnets under Electron Beam Irradiation
Synchrotron radiation is generated when a high-energy electron beam passes through an insertion device — an undulator or a wiggler — that provides a periodic magnetic field. Because the electron trajectory is governed by this field, the magnetic properties of the device, such as field strength and period, directly determine the intensity, wavelength, and directionality of the emitted radiation. Insertion devices are built with either electromagnets or permanent magnets, and among permanent magnets NdFeB is the most widely used material. SmCo is also employed in several facilities, including the Linac Coherent Light Source (LCLS), and is planned for use at the Korea-4GSR multi-purpose synchrotron radiation facility.
The permanent magnets installed in the undulators operating at PLS-II and PAL-XFEL of the Pohang Accelerator Laboratory (PAL) are continuously exposed to radiation produced during beam operation, and their magnetic properties may degrade as a result. Verifying the radiation-induced change of the magnetic field is therefore essential for stable and reproducible synchrotron radiation generation. A previous study at PAL evaluated the magnetic field variation of NdFeB magnets irradiated by a 2.5 GeV electron beam [1]. In the present work, an irradiation experiment was carried out at the PAL-XFEL Main Beam Dump (MBD) in order to reach a considerably higher beam energy than in the earlier study, with the objective of characterizing the change of the magnetic field as a function of the electric charge accumulated on the magnet samples. A related evaluation of electron beam irradiation effects on permanent magnets reported by SOLEIL, a large accelerator facility in France, indicates that the damage threshold of SmCo is more than two orders of magnitude higher than that of NdFeB [2]. Accordingly, two types of permanent magnets, NdFeB and SmCo, were adopted as the study objects so that the effect of electron beam irradiation could be assessed for both materials currently used, or planned to be used, in domestic and overseas light source facilities.
The permanent magnet samples were mounted at the beam center position of the PAL-XFEL MBD, stacked vertically so that several samples could be irradiated simultaneously under the same beam condition while being exposed to different radiation levels depending on their vertical position. Following the approach reported in a previous study [3], the samples were not irradiated directly by the electron beam. Instead, a 4 cm thick copper target was placed in front of the sample assembly so that the samples were exposed to secondary radiation under a well-defined and uniform radiation field. The irradiation was performed continuously over a period of several days using the high-energy electron beam delivered to the beam dump during normal machine operation, and the accumulated charge incident on the assembly was recorded throughout the irradiation.
The residual dose rate at the magnet surface was measured with an ion chamber survey meter (Fluke Biomedical 451P) immediately after irradiation in order to confirm the activation of the samples. After a cooling period of more than two weeks, the three-dimensional magnetic field distribution (X, Y, and Z axes) was mapped at 1 mm intervals using a low-noise magnetic field transducer (SENIS, I3C-03C10L-B02T0K5J). The same measurement was performed before and after irradiation at identical positions so that the difference could be evaluated point by point.
The activation of the irradiated samples was confirmed from the residual dose rate measured near the magnet surface after the irradiation period, and the magnetic field distributions obtained before and after irradiation were compared for each sample. The effect of the electron beam irradiation on the magnetic field of the NdFeB and SmCo permanent magnets, together with its dependence on the accumulated charge, will be discussed.References
[1] R. Qiu, H.-S. Lee, J. Li, T.-Y. Koo, and T. H. Jang, “Radiation damage of Nd2Fe14B permanent magnets at 2.5 GeV electron accelerator,” Nucl. Instrum. Methods Phys. Res. A, vol. 594, no. 2, pp. 111–118, 2008.
[2] J.-B. Pruvost and P. Berkvens, “Challenges in Radiation Safety associated with SOLEIL II Upgrade project,” 12th International Workshop on Radiation Safety at Synchrotron Radiation Sources.
[3] Y. Asano, T. Bizen, and X. Marechal, “Analyses of the factors for the demagnetization of permanent magnets caused by high-energy electron irradiation,” J. Synchrotron Rad., vol. 16, no. 3, pp. 317–324, 2009.Speaker: UkJae Lee (Pohang Accelerator LAboratory) -
39
Conceptual Design of an AI-Based Integrated Environmental Radiation Monitoring System
Environmental radiation monitoring systems are required to provide reliable information on changes in ambient radiation levels and to support the early detection of abnormal radiological events. However, conventional monitoring systems mainly rely on dose-rate measurements, which provide limited information for identifying the origin of radiation level variations. This study presents a conceptual design of an integrated environmental radiation monitoring system combining multiple radiation detectors with artificial intelligence-based data analysis.
The proposed system consists of a high-pressure ionization chamber for ambient gamma dose-rate monitoring, a LaBr₃(Ce) scintillation detector for gamma-ray spectroscopy and radionuclide identification, and a BGO detector for monitoring high-energy radiation components, including cosmic-ray contributions. Radiation measurement data will be analyzed together with environmental and meteorological parameters to distinguish normal background variations from abnormal radiation events. Reference measurements under low-background conditions are also considered for characterizing cosmic-ray contributions and improving the reliability of the analysis. The proposed framework is intended to improve the interpretation of environmental radiation data, support more reliable identification of abnormal events, and reduce false alarms in environmental radiation monitoring.Speaker: Min Ji Kim (IBS) -
40
A KEK–CERN Collaborative Research Program on Radiation Protection for High-Energy Accelerators and Its Experiments
KEK and CERN have shared a common interest in radiation safety at high-energy accelerators. To place this cooperation on a durable and operational footing, the two organisations concluded — within the general framework of their Agreement on Collaborative Work (ICA-JP-0103) — a dedicated implementing appendix (KN6005/HSE, Appendix 28) on the Research and Development of Radiation Protection for High-Energy Accelerators, which entered into force in June 2024 for an initial period of five years. The appendix defines concrete mechanisms that directly enable joint experimental work: the mutual provision of beam time and facilities, the loan of equipment and in-house analytical tools, the exchange of personnel through Visiting Researcher and associated-member status, and joint data analysis with a view to common publication. Its scope includes the generation of benchmark data for Monte Carlo radiation-transport codes, shielding-calculation methodologies, radioisotope production and residual dose rates, the radiological characterisation of accelerator and experiment components, radiation monitoring, and radioactive-waste minimisation. In this contribution we introduce this framework and report on the personnel exchange and experimental programme that KEK and CERN have carried out together since 2015. A particular emphasis is placed on making the resulting data available to the community — through publications that include the full data in numerical form and through their compilation in shielding-benchmark databases such as SINBAD. We hope that this experience can serve as a model for the international cooperation and project implementation that SATIF seeks to foster.
Speaker: Toshiya Sanami (KEK) -
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Evaluation of Monte Carlo shielding calculations in the initial operational phase of RAON
In 2023, Institute for Rare Isotope Science (IRIS) successfully conducted a commissioning test using Rare isotope Accelerator complex for ON-line experiments (RAON) to accelerate a heavy-ion beam to low energy and transmit it to the experimental area. Prior to official operation, the facility must pass a regulatory inspection. In particular, the shielding design section validates the suitability of Monte Carlo-based shielding calculations by measuring dose rates outside the shielding wall during maximum beam power operation. However, during the initial operational phase, outside measurements are impractical due to the extremely low beam power.
In this study, to verify the suitability of the shielding calculation under low-power conditions, a target material with conditions more conservative than the source term of the shielding calculation was used. In addition, neutron and gamma detectors were installed around the beam dump to measure the radiation dose rate during operation, and the suitability was evaluated by comparing these measurements with the Monte Carlo shielding calculation.Speaker: Beomyeol Baek (Institute for Basic Science) -
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Irradiation profiles for Radiation Protection studies for the LHC Experiments for Long Shutdown 3
One of the tasks of the Radiation Protection (RP) group at CERN is to provide forecasts on the radiological classification of the areas within the main LHC experiments (ALICE, ATLAS, CMS, LHCb) and forecasts on the residual dose rates due to the induced radioactivity from the proton-proton and ion-ion collisions. These forecasts can be performed due to a knowledge of the expected luminosity to be delivered. Therefore, the related irradiation profiles will contain real luminosity data from previous operation periods and forecasts for future operation periods.
These predictions are essential to organize in advance the activities in the caverns as the LHC detectors are being upgraded during the Long Shutdown 3 that started on June 29, 2026. These activities will require multiple and prolonged interventions in residual radiation environments and the handling of activated detector components of different nature. An optimization of the dose to personnel will be needed for each intervention.
The RP studies have in common that FLUKA simulations are employed, and there are times in which they can be time consuming. Different approximations on the irradiation profiles could have a significant impact on the radiological quantities but this is not necessarily the case. In order to assess the impact of such approximations on the quantities while avoiding to perform new simulations when the irradiation profile has been changed, the RP group has developed a tool with which the ratio of two radiological quantities is given for each contributing radionuclide when comparing the two irradiation profiles. This results in a set of scaling factors that can be applied for each radionuclide so that the radiological quantity in the new situation can be computed.
Examples of the application of the tool will be presented. These include assessments on proposed changes to the operational schedule of the LHC such as the High Intensity Test period in the 2 weeks before the start Long Shutdown 3 as well as scaling factors for gamma spectroscopy results of activation samples that have been installed in the LHC experimental cavern for a limited period of time in view of the radiological classification of detector or infrastructure components.
In this communication we will present the workflow followed by the RP when providing the irradiation profiles, their consequences in the RP studies and how the tool optimizes the general workflow.
In addition, the first results and observations from the first months of Long Shutdown 3 will be presented.
Speaker: Miguel CABALLERO-PACHECO (CERN) -
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Induced Activity Assessment for the Decommissioning of Synchrotron SOLEIL Storage Ring
The SOLEIL II storage ring upgrade project [1, 2] is ongoing and aims at reducing drastically the horizontal emittance of the electron beam from 4 nm.rad for the present ring down to 80 pm.rad for the SOLEIL II new 4th generation storage ring light source. The corresponding long shutdown is scheduled between end of 2028 and end of 2030, when user operation will resume. The first half year will be dedicated to the deconstruction of all the machine equipment and auxiliary devices that were present in the storage ring during SOLEIL operation within the last 19 years.
During operation, all the 2.75 GeV electrons injected into the storage ring were lost and therefore able to activate the accelerator equipment. This paper will present the history records of the accumulated charges, the losses distribution along the ring and how they are simulated for activation assessment.
According to French Nuclear Regulation Authority (ASNR) requirements, a very detailed 3D model of the accelerator in the concrete tunnel was used to perform very extensive Monte Carlo simulations with the FLUKA code [3, 4]. This paper will present and discuss the results obtained so far and SOLEIL’s foreseen decommissioning strategy and waste management procedure to address to ASNR for authorization clearance.References
[1] J. Susini, “A brief introduction to the Synchrotron SOLEIL and its upgrade programme”, Eur. Phys. J. Plus, vol. 139, no. 80, 2024.
doi:10.10.1140/epjp/s13360-024-04872-2
[2] A. Nadji and L. S. Nadolski, “Upgrade Project of the SOLEIL Accelerator Complex”, Synchrotron Radiat. News, vol. 36, no. 1, 2023.
doi:10.1080/08940886.2023.2186661
[3] C. Ahdida et al., “New Capabilities of the FLUKA Multi-Purpose Code”, Front. Phys. vol. 9, no. 788253, 2022.
https://doi.org/10.3389/fphy.2021.788253
[4] G. Hugo et al., “Latest FLUKA developments”, EPJ Nuclear Sci. Technol., vol. 10, 2024.
doi:10.1051/epjn/2024023Speaker: Jean-Baptiste PRUVOST (Synchrotron SOLEIL)
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6:00 PM
Workshop Dinner at IBS Science Culture Center (Catering Buffet)
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Session 4. Shielding and DosimetryConvener: Irina Popova (Oak Ridge national Laboratory)
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Performances of the novel "TetraBall" single moderator neutron spectrometer at CMS from the analysis of 2025 and 2026 data
This contribution presents the novel single-moderator neutron spectrometer, named "TetraBall", developed by INFN within the CMS BRIL project, aiming at characterizing the complex neutron field in the CMS experimental cavern for the High-Lumi LHC era. The TetraBall is a wide energy range neutron spectrometer condensing the functionality of several Bonner Spheres in a single moderator. It is equipped with 42 SiC radiation-hard detectors organized in a tetrahedral geometry. It is designed to work in a single exposure mode and to be insensitive to incident gammas and charged hadrons. Thanks to a lead insert, exploiting the (n,xn) reaction, it can respond up to several GeV. It is designed to fulfill the CMS BRIL neutron monitoring requirements for the High-Lumi LHC period and it will be fundamental in benchmarking the FLUKA Monte Carlo expectations in several locations inside the underground experimental cavern. The first TetraBall propotype has been installed and commissioned in June 2025 and it has been operated in CMS continuously during the 2025 and 2026 LHC running periods. The unfolded neutron energy spectra, together with the total and partial neutron fluences, measured by the TetraBall system in 2025 and 2026 in different CMS locations will be shown. The results allow the benchmarking of the FLUKA Monte Carlo expectations at the level of 5%.
Speaker: Marco Costa (Universita e INFN Torino (IT)) -
45
Evaluation of the Second Target Station Standard Heavy Neutron Beamline Shutter
The Second Target Station (STS) Project at Oak Ridge National Laboratory (ORNL) is currently completing the final design of components related to Target Systems and Instrument Systems. These components include the rotating water-cooled tungsten target, two liquid-hydrogen moderators, instrument bunker shielding, and many others. Following completion of the Proton Power Upgrade (PPU) at the Spallation Neutron Source (SNS), the proton accelerator now produces 1.3 GeV protons at a frequency of 60 Hz. One quarter of these pulses will deliver 700 kW of beam power to the STS target.
This paper discusses analyses of the prompt dose rates associated with the STS standard heavy neutron beamline shutter when the standard heavy shutter attenuator intercepts the neutron beam inside the instrument bunker. The shutter is closed when the attenuator is rotated into the beam to shut off neutron transmission and allow users to change samples. The standard heavy neutron beamline shutter refers to the full assembly, including the shutter attenuator, drive motor, and associated components. The primary objective of these analyses is to evaluate the performance of the shutter attenuator downstream of the shutter, in the direction of the instrument sample location.
There are two major design requirements for the standard heavy neutron beamline shutter:
1) The standard heavy shutter attenuator shall reduce the total effective dose rate to less than 2 mrem/h at 3 m from the downstream face of the attenuator in white beam.
2) The instrument bunker shielding shall limit the total effective dose rate outside the bunker to less than 0.25 mrem/h at 30 cm from surfaces in generally accessible areas, including when the standard heavy shutter is in the closed position.These analyses were completed using MCNP 6.2. The results show that the standard heavy shutter design meets the specified design requirements with an attenuator consisting of twenty-nine 2.5 cm thick plates. The first twenty plates on the upstream (moderator) side are tungsten, and the remaining nine plates on the downstream (instrument) side are carbon steel.
This paper also describes model creation using GEOUNED, generation of variance reduction parameters with ADVANTG, and the methodology used to ensure adequate sampling of neutrons traveling along the beamline. It also compares these results with those for the primary shutters at the Spallation Neutron Source.
Speaker: Thomas Miller (Oak Ridge National Laboratory) -
46
ISOLDE Beam Dump Replacement: FLUKA residual dose rate calculations for radiological planning
The ISOLDE (Isotope Separator On-Line DEvice) facility at CERN produces radioactive ion beams for research in nuclear, atomic and solid-state physics using thick targets irradiated with a 1.4 GeV / 2 microA (2.8 kW) proton beam. The facility comprises two target stations, each equipped with a dedicated beam dump located about two metres downstream of the target. The beam dumps are surrounded by concrete shielding blocks and buried beneath several metres of soil.
To support future operation with a proton beam of up to 2 GeV and 6 microA (12 kW), the ISOLDE target area is being upgraded as part of the IBDRS (ISOLDE Beam Dump Replacement & Sustainability) project. The project, which is being carried out during ISOLDE’s Long Shutdown 3 (LS3, 2026–2027), includes the excavation of the soil above the beam dumps, their replacement and the reinforcement of the surrounding shielding.
Since the shielding blocks and beam dumps had remained largely inaccessible throughout the last 30 years of operation, neither their physical condition, relevant for handling and transport, nor the residual dose rates could be assessed in advance. The expected high dose rates and the uncertainty regarding the condition of the components made the planning of the dismantling particularly challenging.
This work presents the residual dose rate calculations carried out with the FLUKA Monte Carlo code to support the radiological planning of the dismantling of the existing beam dumps. As direct radiation measurements were not possible before the start of the work because the radioactive components were inaccessible, the simulations formed the basis for the step-by-step dose planning and the optimisation of the work in accordance with of the ALARA principle. They were used to estimate the maximum individual and collective doses associated with each stage of the dismantling sequence, from the initial configuration to the complete removal of the shielding and beam dump blocks. Additionally, a photon skyshine analysis was performed to evaluate the contribution of photon scattering in air to dose rates at larger distances from the worksite.
Once the shielding became accessible at the end of the excavation phase, radiation measurements were performed. The FLUKA predictions were benchmarked against these measurements, demonstrating very good agreement and confirming the reliability of the calculations across the dismantling sequence.Speaker: Victor Garcia Balcaza (CERN) -
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Japanese Shielding Material Standard for facility design (Concrete Edition)
In the construction of accelerator facilities in Japan, the concrete to be placed has not been decided at the time of shielding calculations. Therefore, shielding calculations are carried out with concrete compositions selected by the designers, e.g. from ANL-5800 (USA). However, the composition is not data for concrete in Japan, and the basis for the data is also unclear.
We have been developing a standard through a working group of the Atomic Energy Society of Japan (AESJ). The concrete composition data for shielding calculation was made based on the research results of Architectural Institute of Japan.
The concrete composition data defined two types of concrete composition: concrete using Si-based aggregates (andesite and sandstone) often used in Japan, and concrete using Ca-based aggregates (limestone).
The application of the concrete composition data is accelerator facilities below 20MeV (such as PET facilities). Accelerators with 20 MeV or more will be handled separately. This composition is not only applicable in accelerator facilities, but also in nuclear facilities and RI handling facilities.
Because the amount of moisture in concrete changes with wall thickness and age, a compositional correction equation for moisture was also established. Furthermore, in Japan, since the density of concrete is specified by customers in some cases, the correction formula of composition for density was also determined.
When the concrete to be placed is clear, the composition data actually analyzed may be used.
The developed concrete composition data will be published as the Atomic Energy Society of Japan standards.Speaker: Koichi Okuno (Hazama-Ando Corporation)
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10:00 AM
Coffee Break
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Session 4. Shielding and DosimetryConvener: Irina Popova (Oak Ridge national Laboratory)
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Radiations from 7Li(p,n)+235U RIB source; Monte Carlo Radiation Transport Simulations and Measurements
A 7Li(p,n) reaction and 235U system will replace the 252Cf based radioactive ion beam source at the Argonne Tandem Linac Accelerator System (ATLAS) accelerator. Re-purposing a room with no shield walls that housed a 252Cf source based RI source with a 30 kW intense n-γ producing source posed challenges from the radiation physics and operational radiation protection perspectives. FLUKA and PHITS Monte Carlo codes were used to study the radiation environments, with identical geometries and material compositions. Both codes predicted almost identical solid angle-integrated yields and directional doses from the 7Li(p,n) reaction for photons and neutrons. The number of fissions in the 235U foil predicted by PHITS was about 2 times higher than FLUKA, at 109 fissions per second. Comparison of photon spectra, due to the transport of neutrons and photons across the complex geometry, showed reasonable agreement in the shape and differential yield, but PHITS overpredicted the annihilation peak by a factor of a few and did not predict some of the peaks present in the FLUKA output, particularly from the Mo and Zr layers. The neutron spectrum and dose predicted by the codes were in good agreement. While the polyethylene/Masonite shielding showed good efficacy in reducing the neutron doses to less than 5 μSv/h, the prompt gamma dose required additional shielding. Weight considerations ruled out lead as the additional shield, and concrete was chosen to reduce the dose in the general public area. Induced activity was the highest in the target from 7Be, at 1012 Bq after one month of operation, followed by the Mo window. PHITS predicted about 2 orders of magnitude lower 7Be activity. Residual dose was estimated after shutdown without disturbing the shielding, and also from the target holder when it was removed after shutdown. For the latter scenario, the effect of a steel cask in reducing the dose was studied. Argonne’s radiation protection practices will be relied upon to keep the prompt and residual doses in other locations As Low As Reasonably Achievable (ALARA).
Speaker: Sunil Chitra (Argonne National Laboratory) -
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Remarks on neutron production of proton-induced 7Li nuclear data
Accurate neutron production cross sections are essential for the design and operation of accelerator-based neutron sources, as they directly affect predictions of neutron yield, energy spectra, and shielding performance.
In this study, neutron production cross sections for the p-Li reaction contained in two major nuclear data libraries, ENDF/B-VIII.0 and JENDL-5, were comparatively evaluated, because lithium is one of the most widely used target materials for accelerator-based neutron source. Significant discrepancies were identified between the two libraries for proton energies above 10 MeV. The differences were found to originate primarily from the treatment of reaction channels contributing to neutron production. Consequently, noticeable discrepancies were observed in both the shape and absolute values of the neutron production cross sections.
Although JENDL-5 showed better consistency than ENDF/B-VIII.0, further validation against experimental data is required for both libraries. Benchmark analyses using p-Li neutron production experiments at the Nuclear Physics Institute of the Czech Academy of Sciences and at CYRIC, Tohoku University, indicate that JENDL-5 reproduces the measured neutron spectra more reasonably than ENDF/B-VIII.0. Nevertheless, noticeable discrepancies in peak energy and neutron yield remain, highlighting the need for further improvement and validation of the evaluated nuclear data.Speaker: Saerom Kwon (National Institutes for Quantum Science and Technology (QST)) -
50
Discussion : Session 4b. Shielding and Dosimetry
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48
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Session 5. Induced radioactivity and decommissioningConvener: Dali Georgobiani (Fermilab)
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51
Estimation of Residual Activity in a Molybdenum Research & Development Experiment using FLUKA, MCNP and PHITS
Argonne National Laboratory successfully ran a Molybdenum Research Experiment (AMORE) to study production of \textsuperscript{99}Mo in which accelerator-driven subcritical fission of an aqueous LEU uranyl sulfate solution was demonstrated using an electron accelerator. Depleted uranium was used as the electron-to-photon converter and the neutrons produced irradiated a 20-liter uranyl sulfate solution (145 g/liter of uranium enriched to just under 20\%) which was surrounded by a water reflector tank. The geometry was constructed for MCNP and was exported to FLUKA and PHITS using FLAIR Graphical User Interface. The target and solution were contained in a lead shielded cell. The experiment produced 87.5 mCi of 99Mo/kWh-kg-\textsuperscript{235}U. Once the experiment was concluded, the uranyl sulfate solution was drained off, and the remaining components were kept for Decontamination and Decommissioning (DnD). The components were characterized for the residual activity, radionuclide distribution and residual dose rates. While FLUKA was used to estimate the residual dose rates, MCNP/CINDER and PHITS along with FLUKA were used to estimate the residual activity and residual nuclei distribution. To address some of the differences in the yield of radionuclides, PHITS calculations were repeated with ENDF/B-VIII coupled with CP2020, JEFF 4.0 in addition to the default JENDL5 PHITS uses. Residual activity from MCNP results were obtained from MCNP/CINDER calculations. MCNP simulations used cross section table for neutrons below 20 MeV (coinciding with the highest energy in most of the CINDER data libraries) and model physics above. In addition, model physics was used to determine residual nuclides from photonuclear reactions and from neutron-induced reactions with En > 20 MeV.
Experiments were run at 8-17 kW beam power at 40 MeV electron energy over 3 years, between 2018-2021. The exact irradiation history was used in calculations to estimate the residual nuclide yield after 5 years of cooling.
Depleted uranium had the highest activity at about \num{4.7E8} Bq, dominated by \textsuperscript{147P}m at 21\%, \textsuperscript{137}Cs at 16\%, \textsuperscript{137m}Ba at 15\%, \textsuperscript{90}Y and \textsuperscript{90}Sr at about 11\% each, and \textsuperscript{125}Sb at 8\%. These were followed by the \textsuperscript{106}Ru/\textsuperscript{106}Rh and \textsuperscript{144}Ce/\textsuperscript{144}Pr parent-daughter pairs, each at about 3\% per nuclide. FLUKA and MCNP agreed in terms of the highest yield radionuclides while PHITS predicted \textsuperscript{137}Cs as the highest yield radionuclide followed by \textsuperscript{147}Pm, for all cross-section data used. A notable difference in the depleted U converter was the yield of \textsuperscript{239}Pu which was ~ 7 times lower in FLUKA comparted to MCNP/CINDER while PHITS reported 30\% of MCNP results. The lower yield of \textsuperscript{239}Pu in FLUKA was attributed to the lower GDR photoneutron yield in the 20-40 MeV energy range, because of the Bezier fits used. Within PHITS, the three data sets gave almost the same yield, not only for \textsuperscript{239}Pu but also for the other radionuclides except for 14C which showed 12\% lower yield with ENDF data. Results from the simulations will be discussed for depleted U as well as the other components.Speaker: Sunil C. (Argonne National Laboratory) -
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Experimental Validation of FLUKA Predictions for Induced Radioactivity in Accelerator Materials at the Advanced Light Source
Accurate prediction of induced radioactivity is essential for accelerator lifecycle management, radioactive waste characterization, radiological zoning, and radiation protection. At the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory (LBNL), an experimental program was developed to benchmark FLUKA predictions of beam-loss-induced activation using irradiated metal samples installed in the accelerator complex.
Representative samples of stainless steel, copper, and aluminum were installed at selected locations along both the electron storage ring and photon beamline front ends inside the accelerator tunnel. Samples were positioned at different distances from electron beam-loss locations, including positions directly adjacent to accelerator components, approximately 30 cm from the beam axis, and near shielding walls. This configuration provides experimental data for evaluating the spatial distribution of induced radioactivity and validating predictions under different radiation field conditions.
A detailed FLUKA Monte Carlo model [1, 2, 3] was developed to predict beam-loss-induced activation of representative material samples using realistic accelerator geometry, material composition, sample locations, and operational beam parameters. Following irradiation, the samples are analyzed by high-resolution gamma spectrometry to determine radionuclide inventories and specific activities. The measured activities are compared with FLUKA predictions to benchmark beam-loss models, evaluate predicted activity distributions, and quantify uncertainties relevant to accelerator activation assessments and radioactive waste characterization.
This work demonstrates an experimental approach for validating Monte Carlo predictions of induced radioactivity in a synchrotron radiation facility. The validated simulation methodology will improve confidence in activation assessments at ALS and support radioactive waste classification, radiological zoning, and ALARA-based decision-making for accelerator maintenance, upgrades, and future decommissioning activities.
[1] G. Battistoni, et al., "Overview of the FLUKA code", Annals of Nuclear Energy 82, 10-18 (2015).
[2] C. Ahdida, et al., "New Capabilities of the FLUKA Multi-Purpose Code",
Frontiers in Physics 9, 788253 (2022).
[3] FLUKA website: https://fluka.cernSpeaker: Patrycja Dyrcz -
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Radiation Protection Studies for BDF/SHiP at CERN
CERN’s planned Beam Dump Facility (BDF) developed within the HI-ECN3 project will host the Search for Hidden Particles (SHiP) experiment, a next-generation facility designed to explore light dark matter and other hidden sector particles. At the core of the BDF is a tungsten target designed to absorb most of the particle cascade produced by the high intensity 400 GeV/c proton beam and surrounded by a massive shielding. Over its five-year design lifetime, corresponding to an integrated beam intensity of 2E20 protons on target (POT), the target is expected to reach extreme levels of activation.
To ensure compliance with CERN radiation protection regulations and to maintain occupational exposures and environmental impacts as low as reasonably achievable (ALARA), comprehensive radiation protection studies have been performed using the FLUKA Monte Carlo particle transport code.
In this work, the residual dose rates of the BDF target complex and radionuclide inventories of its most critical components were evaluated. Dedicated handling studies were performed to define feasible maintenance and replacement scenarios, demonstrate the need for remote operations, and identify the shielding and access provisions required to minimise personnel exposure. Particular attention was given to the BDF target as the most critical component from a radioactive waste perspective, including studies of its waste classification and the requirements for packaging, transport, and final disposal.
Speaker: O. L. Pinto
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12:10 PM
Lunch
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Session 6. Radiation damage to materialsConvener: Dali Georgobiani (Fermilab)
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Radiation Damage Assessment of Korea-4GSR Storage Ring Components Induced by Synchrotron Radiation
The Korean light source, which is a 4th-generation storage ring, has been planned and launched since July 2021. The electron beam is accelerated to 200 MeV in the linac, then injected into the booster ring, reaching 4 GeV before being injected into the storage ring. The stored current is 400 mA and the 2 mA electron beam is injected into the storage ring every 2 min. The storage ring has 28 symmetrical cells with a beam emittance of 62 pm·rad. The storage ring circumference is 799.297 m, and both the storage ring and booster ring are located in the same tunnel.
The storage ring utilizes a Multi-Bend Achromat (MBA) lattice design. Along the storage ring, magnets generate synchrotron radiation that penetrates or is scattered from the storage ring vacuum chamber and impinges on nearby materials such as cables and water hoses. These scattered photons deposit energy in the surrounding materials. This energy deposition consequently causes material damage. The vacuum group identified critical radiation-exposed locations at CN05, CN06, CN10, and CN12. To assess radiation damage risk, a detailed geometric model of the storage ring cell was simulated using FLUKA 4-5.0 (CERN version) [1]. Synchrotron radiation spectra generated by the storage ring magnets were calculated using the SPECTRA [2] code and subsequently transported through the detailed geometric model in FLUKA. Two representative materials with contrasting radiation resistance, polytetrafluoroethylene (PTFE), known as Teflon (low resistance), and epoxy (high resistance), were evaluated. Deposited energy and estimated material lifetimes were determined. The lowest radiation resistance thresholds of 0.3 and 100 kGy [3] were selected for Teflon and epoxy, respectively, as a conservative approach.
Results demonstrate that epoxy exhibits sufficient radiation resistance for all considered critical locations throughout the facility lifetime. In contrast, Teflon is predicted to suffer significant radiation damage, e.g., around CN06, with an estimated operational lifetime of only 5 months. This estimation is very conservative. However, protective measures are recommended: either replacing Teflon with a more radiation-resistant polymer such as polyetheretherketone (PEEK) or installing lead shielding to mitigate photon exposure to Teflon components.
These results demonstrate the necessity of radiation damage estimation for the materials around the storage ring [4].References
[1] C. Ahdida et al., New capabilities of the FLUKA multi-purpose code, Front. Phys. 9 (2022).
[2] T. Tanaka and H. Kitamura, SPECTRA: a synchrotron radiation calculation code, J. Synchrotron Radiat. 8 (2001).
[3] H. Schönbacher et al., Compilation of Radiation Damage Test Data: Part II, 2nd edition: Thermoset and Thermoplastic Resins, Composite Materials, CERN 98-01 (1998).
[4] P. Berkvens et al., The ESRF Extremely Brilliant Source (EBS), the 11th International Workshop on Radiation Safety at Synchrotron Radiation Sources (RADSYNCH 2023), Grenoble, France (2023).Speaker: Mahdi Bakhtiari (Pohang Accelerator Laboratory, POSTECH, Pohang, South Korea) -
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Summary of LCLS-II FEL Bootstrap Testing and Plan for LCLS-II-HE Testing
The LCLS-II is a superconducting linear accelerator that can generate 4 GeV electrons at repetition rates up to 1 MHz and is used at SLAC to generate a free electron laser (FEL) ranging between 200 eV and 4 keV for a variety of user experiments at the LCLS science hutches. As the FEL beam has very high brightness and can operate at high repetition rates, understanding its interactions with various materials is crucial for adequately developing and deploying radiation safety systems that can mitigate the primary hazard of the FEL beam, which is burning materials meant to contain the beam, and exposing a person to radiation. The design of radiation safety systems was performed using conservative assumptions and modeling; however, there is still uncertainty in the response of the system. To gain confidence in the system, a series of tests referred to as “bootstrap tests” has been developed for LCLS-II.
This talk will summarize the results of the bootstrap testing and provide experimental data related to FEL interactions with matter that are important to radiation safety. Some key experimental results include the confirmation of the tunneling effect for high repetition rate FEL beams in air, and characterization of the drill speed and hole formation of FEL beams burning materials relevant to radiation safety.
A look forward will also be presented to LCLS-II-HE, which extends the electron beam energy to 8 GeV while maintaining the high repetition rate capability, and the bootstrap plan that has been developed to address new hazards and the analysis that has been developed to mitigate hard x-ray beam hazards. Specific focus will be placed on new testing related to the ability of materials to withstand certain FEL exposure conditions and testing specific to hazards from hard x-ray diffraction.
This work was supported by Department of Energy contract DE-AC02-76SF00515.
The LCLS-II is a superconducting linear accelerator that can generate 4 GeV electrons at repetition rates up to 1 MHz and is used at SLAC to generate a free electron laser (FEL) ranging between 200 eV and 4 keV for a variety of user experiments at the LCLS science hutches. As the FEL beam has very high brightness and can operate at high repetition rates, understanding its interactions with various materials is crucial for adequately developing and deploying radiation safety systems that can mitigate the primary hazard of the FEL beam, which is burning materials meant to contain the beam, and exposing a person to radiation. The design of radiation safety systems was performed using conservative assumptions and modeling; however, there is still uncertainty in the response of the system. To gain confidence in the system, a series of tests referred to as “bootstrap tests” has been developed for LCLS-II.
This talk will summarize the results of the bootstrap testing and provide experimental data related to FEL interactions with matter that are important to radiation safety. Some key experimental results include the confirmation of the tunneling effect for high repetition rate FEL beams in air, and characterization of the drill speed and hole formation of FEL beams burning materials relevant to radiation safety.
A look forward will also be presented to LCLS-II-HE, which extends the electron beam energy to 8 GeV while maintaining the high repetition rate capability, and the bootstrap plan that has been developed to address new hazards and the analysis that has been developed to mitigate hard x-ray beam hazards. Specific focus will be placed on new testing related to the ability of materials to withstand certain FEL exposure conditions and testing specific to hazards from hard x-ray diffraction.
This work was supported by Department of Energy contract DE-AC02-76SF00515.Speaker: Andrew Rosenstrom (SLAC National Accelerator Facility) -
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Discussion : Session 5b. Induced radioactivity and decommissioning & Session 6. Radiation damage to materials
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54
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2:15 PM
Coffee Break
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Concluding Session: Summary, future actionsConvener: Nam-Suk Jung (Pohang Accelerator Laboratory / POSTECH)
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