Vibration Reduction in a Pulse Tube-Cooled High Purity Germanium Detector

Abstract

High-purity germanium (HPGe) is a vibration-sensitive, high-resolution detector. It has been found that microphonic noise induced by vibration and electromagnetic interference from EMC causes energy resolution degradation in HPGe detectors. In this paper, to enhance the energy resolution of a pulse tube-cooled high purity germanium detector, a passive vibration isolation system for the portable pulse tube cooler (PTC) was employed and investigated. In order to evaluate the performance of the vibration isolation system, micro-vibration tests of the compressor with a vibration isolation kit and detector mounting interface were performed. Meanwhile, detector energy resolution and detector signal noise were tested, respectively, under the PTC, with the isolation system switched to either an on or off condition. The test results indicate that the effectiveness of passive vibration isolation techniques is confirmed, and no degradation was induced by PTC vibration on detector energy resolution.