Mechanically-cooled germanium detector using two Stirling refrigerators

In this paper, we present a developed mechanically-cooled germanium gamma-ray detector using Stirling refrigerators. Two Stirling refrigerators having cooling faculty of 1.5 W at 80 K were used to cool down a germanium detector element to 77 K instead of a dewar containing liquid nitrogen. An 145 cm³ (56.0 mmf×59.1 mml) closed-end Ge(I) detector having relative detection efficiency of 29.4% was attached at the refrigerators. The size of the detector was 60 cml×15 cmh×15 cmw. The lowest cooling temperature, 70 K was obtained after 8 hours operation. The energy resolutions for 1.33 MeV gamma-rays and for pulser signals were 2.43 keV and 1.84 keV at an amplifier shaping time of 2 μsec, respectively