Performance of a 60 gram cryogenic germanium detector

A 60-g particle detector which utilizes the ionization and the phonons produced by a particle interaction has been developed. Six NDT (neutron transmutation doped) Ge thermistors are attached to a pure germanium crystal which has implanted contacts for drifting charge. The authors have operated the detectors at 30 mK and have studied its response to irradiation by 18- and 60-keV photons from an /sup 241/Am source. An analysis of the resolution of the detector which addresses the noise of the front-end electronics and signals from extraneous sources such as microphonics is presented. The simultaneous measurement of phonons and ionization has been demonstrated to have a resolution of 4 keV. This joint detection should prove to be very valuable in distinguishing between candidate dark matter interaction events and competing background processes.<
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