Development of High Resolution Homogeneous Calorimeter Using Liquid Xenon

点击翻译按钮获取中文摘要

In this scientific research project we have developed high resolution homogeneous calorimeter using liquid xenon.This new type of calorimeter uses liquid xenon as the active medium that emits UV scintillation lights upon incidence of gamma rays and electrons. A number of photomultiplier tubes (PMTs) surrounding the liquid xenon measure these scintillation lights. The calorimeter does not contain any passive material like electrodes in the liquid xenon volume, thus can fully observe all the energy deposits.We mostly concentrated on developments of various technologies necessary to realize a large volume (an order of 1,000 liters or 3 tons) detector.Liquid xenon as the detector medium is guaranteed to be perfectly uniform, however, some impurity contamination, if it exists, absorbs the scintillation light and could deteriorate the performance of such a large volume device. We successfully developed a new, efficient purification method to remove impurities very quickly by circulating liqu … More id xenon through molecular sieves using a cryogenic centrifugal liquid pump. We also developed methods and techniques for xenon transfer, xenon pressure/temperature control, safety precaution, etc. These are necessary for practical application of a large volume liquid xenon detector.We examined the performance of a liquid xenon detector by using π^0 decays. In this test we collected waveform data of PMTs and proved that we can distinguish incident gamma-rays from alpha particles. We also succeeded in developing a new type of PMTs with photocathode and base circuit that can sustain very high background rates even at low temperatures. Computer codes were developed to simulate the detector response and were shown to agree very well with the observed data.An avalanche photodiode (APD) was operated and tested in liquid xenon. The APD is very compact and has a very high quantum efficiency. The success of this test opened up extensive future applications such as monitoring of absorption length. Less