Intrinsic background radiation of LaBr3(Ce) detector via coincidence measurements and simulations

• Published in: Nuclear science and techniques 2020-10, Vol.31 (10), p.33-42, Article 99
• Main Authors: Cheng, Hao, Sun, Bao-Hua, Zhu, Li-Hua, Li, Tian-Xiao, Li, Guang-Shuai, Li, Cong-Bo, Wu, Xiao-Guang, Zheng, Yun
• Format: Article
• Language: English
• Subjects: Energy; Hadrons; Heavy Ions; Nuclear Energy; Nuclear Physics
• ISSN: 1001-8042; 2210-3147
• DOI: 10.1007/s41365-020-00812-8

The LaBr 3 (Ce) detector has attracted much attention in recent years because of its superior characteristics compared with other scintillating materials in terms of resolution and efficiency. However, it has a relatively high intrinsic background radiation because of the naturally occurring radioisotopes in lanthanum, actinium, and their daughter nuclei. This limits its applications in low-counting rate experiments. In this study, we identified the radioactive isotopes in the ϕ 3 ′ ′ × 3 ′ ′ Saint-Gobain B380 detector by a coincidence measurement using a Clover detector in a low-background shielding system. Moreover, we carried out a Geant4 simulation of the experimental spectra to evaluate the activities of the main internal radiation components. The total activity of the background radiation of B380 is determined to be 1.523 (34) Bq/cm 3 . The main sources include 138 La at 1.428 (34) Bq/cm 3 , 207 Tl at 0.0135 (13) Bq/cm 3 , 211 Bi at 0.0136 (15) Bq/cm 3 , 215 Po at 0.0135 (3) Bq/cm 3 , 219 Rn at 0.0125 (12) Bq/cm 3 , 223 Fr at 0.0019 (11) Bq/cm 3 , 223 Ra at 0.0127 (10) Bq/cm 3 , 227 Th at 0.0158 (22) Bq/cm 3 , and 227 Ac at 0.0135 (13) Bq/cm 3 . Of these, the activities of 207 Tl, 211 Po, 215 Po, 223 Fr, and 227 Ac are deduced for the first time from the secular equilibrium established in the decay chain of 227 Ac.