Study of radioactive impurities in neutron transmutation doped germanium

作者：Mathimalar S; Dokania N; Singh V; N**** V^*; Pillay R G; Shrivastava A; Jagadeesan K C; Thakare V

来源：Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment , 2015, 774: 68-73.

DOI：10.1016/j.nima.2014.11.056

• Neutron transmutation doping
• Radioactive impurities
• gamma-Rays

A program to develop low temperature (mK) sensors with neutron transmutation doped Ge for rare event studies with a cryogenic bolometer has been initiated. For this purpose, semiconductor grade Ge wafers are irradiated with thermal neutron flux from Dhruva reactor at Bhabha Atomic Research Centre (BARC), Mumbai. Spectroscopic studies of irradiated samples have revealed that the environment of the capsule used for irradiating the sample leads to significant levels of Zn-65, Ag-110m and Ta-182 impurities, which can be reduced by chemical etching of approximately similar to 50 mu m thick surface layer. From measurements of the etched samples in the low background counting setup, activity due to trace impurities of Sb-123 in bulk a is estimated to be similar to 1 Bq/g after irradiation. These estimates indicate that in order W use the NTD a sensors for rare event studies, a cooldown period of similar to 2 years would be necessary to reduce the radioactive background to <= 1 mBq/g.

• 出版日期2015-2-21