Monte Carlo study of reduction of inherent Pb-210 decay chain emissions from shielding in whole body counters

被引：0
作者：
Mendes, Bruno Melo [1 ]
Meira-Belo, Luiz Claudio [1 ]
Souza, Guilherme Cavalcante de Albuquerque [1 ]
de Campos, Tarcisio Passos Ribeiro [1 ]
机构：
[1] Ctr Desenvolvimento Tecnol Nucl CDTN CNEN, Ave Presidente Antonio Carlos 6-627, BR-31270901 Belo Horizonte, MG, Brazil
来源：
RADIATION PHYSICS AND CHEMISTRY | 2025年 / 230卷
关键词：
Pb-210; Decay chain; Whole body counter; Shielded cabin; ENERGY PHOTON EMITTERS; BREMSSTRAHLUNG; CALIBRATION; LEAD;
D O I：
10.1016/j.radphyschem.2025.112548
中图分类号：
O64 [物理化学（理论化学）、化学物理学];
学科分类号：
070304 ; 081704 ;
摘要：
In vivo monitoring systems require shielding that significantly reduces the contributions of environmental background radiation. Lead is a material extensively used in shielding against ionizing radiation. However, contamination with Pb-210 and radioactive elements from its decay chain may make using this material for shielding in vivo systems unfeasible. Thus, this study aims to evaluate the contribution of the Pb-210 and its decay chain emissions generated by the lead shielding and detected in a NaI(Tl) scintillator positioned in the center of a lead cabin. The means of attenuating these emissions were also evaluated. The contributions of photon, beta, and monoenergetic electron emissions from the main radionuclides in the Pb-210 chain were computationally evaluated in a NaI(Tl) detector inside a 13 cm thick shielded cabin. Zinc, copper, and tin plates with 1-, 3-, and 5 mm thicknesses were tested to attenuate the Pb-210 decay chain contributions. The percentage reduction factor was calculated for the total count rate and different energy ranges. Bremsstrahlung photons generated by beta particles emitted by Bi-210 constitute the main contribution of Pb-210 and its decay chain. Gamma photons from Pb-210 also represented a relevant contribution to the simulated in vivo system. Among the materials tested, Tin demonstrated the highest efficiency for shielding emissions from the Pb-210 decay chain in all energy ranges studied. Zinc offered the best cost/attenuation ratio. Copper plates presented intermediate performance. Future studies will evaluate whether the inclusion of a layer of low-Z material between the lead and the tested shielding materials can improve the attenuation of bremsstrahlung-generated photons.
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