Virtual Frisch-grid ionization chambers filled with high-pressure Xe

摘要

New approaches to the design of high-pressure Xe (HPXe) ionization chambers are described. HPXe ionization chambers represent a well-known technique for detecting gamma rays in the energy range between 50 keV and 3 MeV. Since the HPXe detector is an electron-only carrier device, its commonly accepted design includes a Frisch-grid—a metal mesh employed for the electrostatic shielding from the slowly drifting positive ions. The grid is a key element of the device's design which enables good energy resolution of the detector, typically 2-3% FWHM at 662 keV. However, the grid makes the design more complex and less rugged, especially for the field applications. Recently, we developed several designs of HPXe ionization chambers without shielding grids. The results obtained from the testing of these devices are presented here.