Speaker
Description
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.cern
| Topics | T5. Induced radioactivity and decommissioning |
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