Fast timed active shield for a gamma-ray spectrometer

Abstract

The operational problems of the gamma ray spectrometer shielded passively with 12 cm of lead and actively by five 0.5 m x 0.5 m x 0.05 m plastic veto shields are described. In the present paper we describe the new results of our ground based actively shielded extended range low level gamma spectrometer emphasizing the anticoincidence timing details which are unavoidable for the proper operation of the system After the new adjustment of active shield germanium system, total count rate in anticoincidence background spectrum was 0.38 c/s (50 keV-2 MeV), the achieved reduction factor with respect to the passively shield background spectrum is 2.42. The 51 1 keV reduction factor is 4.25.