Compton suppression spectrometer with parallel sampling model of anti-coincidence counting system

Compton suppression spectrometer for the measurement of low background γ ray has adapted the anti-coincidence counting system of parallel sampling model and an effective material shielding, also automatic data collecting and processing. In the well-type anti-coincidence model, the detecting sensitivity was 2.02 pCi for 137Cs standard thin-film source which was placed above 3.5 cm from NaI(Tl) main detector. Integral background was 115 cpm in the energy range 50 ∼ 2000 keV. Compared to the model without anti-coincidence, it was reduced by 61.5%