Radiopurity studies of a rock sample from the Aut region

Efforts are underway to set up an underground laboratory in India for rare event studies like double beta decay, dark matter, etc. For such experiments, mitigation of radiation background is of paramount importance and understanding ambient background at the site, originating from the rock, is one of the crucial factors. With this motivation, the radiopurity studies of a rock sample from the potential laboratory site in the Aut tunnel of Himachal Pradesh (India) have been carried out using the TIFR low background experimental setup (TiLES). The concentration of K-40 in Aut rock is observed to be lower by a factor of ~1000 as compared to the samples from BWH (Bodi West Hill), Tamil Nadu (India), current designated site for India-based Neutrino Observatory. The natural radioactive trace impurity Th-232 is lower in the Aut rock, while U-238 is somewhat higher than the BWH rock. Overall, the ambient gamma ray background at Aut is expected to be lower than the BWH, while ambient neutron background is expected to be similar. Further, to assess the neutron-induced long lived activity, fast neutron activation studies have been carried out on both the Aut and BWH rock samples at the Pelletron Linac Facility, Mumbai.

Automated summary

Efforts are being made to establish an underground laboratory in India for rare event studies. Researchers have conducted radiopurity studies on rock samples from the potential laboratory site, finding lower levels of radiation contamination compared to other sites. This is significant for reducing radiation background. Additionally, neutron-induced activity was assessed through experiments.