A cryogenically cooled single-crystal BGO anti-Compton spectrometer

The construction and experimental results of a novel compact anti-Compton spectrometer system are reported. The device consists of a large BGO scintillation crystal with a cylindrical well. Inside the well, a 56 mm diameter, 57 mm high (n-type) germanium crystal is mounted. The entire assembly is cooled down to 104 K. Scintillation light from the BGO crystal is detected by a 127 mm diameter PM tube. The assembly has the advantage of a compact design and the absence of any material between the Ge and the BGO crystal. A peak-to-total ratio of 0.60 is obtained with a /sup 60/Co source and 0.74 with a /sup 137/Cs source.<
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