HPGe Systems HPGe Systems Author: Tim This page is dedicated to providing a step-by-step setup of an HPGe system The graded shield uses 4-inch thick walls of low background lead, layered with tin and copper to suppress x-rays excited by the lead. There is a small hole at the bottom of the shield for the HPGe cryogenic dip-stick to exit the shield and enter the externally held liquid nitrogen. A small slot permits the necessary cabling to also enter the shield. These include the detector HV, preamp power, test signal in, energy pulse out, and HV inhibit out. The preamplifier is house in the bottom section of the detector. Slowly lower through the shield into the dewar. The underneath view. The fully seated detector.