Low-pressure multisteo detector for very low energy heavy ions

Abstract

We describe a large-area timing and position-sensitive multistep gaseous detection heavy ions. It consists of a preamplification stage operating as a parallel plate avalanche chamber directly coupled to a multiwire proportional chamber. The detector operates at a pressure range of 1–4 Torr, with very thin window foils. The principle of operation and the performance of the detector when used with various ions are presented. It has a high gain and good time resolution (better than 180 ps fwhm) and localization properties (better than 0.2 mm (fwhm)). Its efficiency for low energy high mass ions was tested with 160Gd ions and found to be 93% (equal to the electrode transparency) down to kinetic energies of 1.3 MeV.