Background modelling for the TEXONO experiment

TEXONO collaboration is pursuing a research program on low energy neutrino and dark matter physics at the Kuo-Sheng Neutrino Laboratory (KSNL). The KSNL is located at a distance of 28 m from a 2.9 GWt (thermal) reactor core with around 30 MWE (meter water equivalent) overburden. The current goal of collaboration is to develop novel detectors with kg scale target mass, 100 eV sensitivity and extremely low-background to study the neutrino-nucleus coherent scattering. The main detector of TEXONO experiment is point-contact High Purity Germanium (PCGe), which is widely used for various experimental investigations, such as dark matter experiments, neutrino experiments and double beta-decay experiments. We present a background model for PCGe that is located in the KSNL under 50-ton passive shielding house. It is impossible to completely remove the background events, but the background level can be suppressed by employing proper shielding material. The background analysis of the detector plays a pivotal role in finding the contaminants present in the different components of the detector, shielding around the detector and the surrounding. In order to include the cosmic ray induced background, intensive studies are in progress