17th Workshop on Shielding Aspects of Accelerators, Targets, and Irradiation Facilities (SATIF-17)

Monte Carlo Benchmarking of Concrete Activation Induced by 9.7 GeV Electrons at PAL-XFEL

Oct 20, 2026, 3:35 PM

20m

IBS Science Culture Center, Daejeon, Korea

Oral Session 3. Code benchmarking and intercomparison

Speaker

Euna Lee (Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea)

Description

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.