A multistep avalanche chamber with optical readout for use as a 2-dimensional VUV photon or particle track detector

Abstract

Abstract A multistep avalance chamber with optical readout has been built and tested as a position sensitive VUV photon detector for use in Cherenkov ring imaging and as a particle track detector. Readout of the chamber, which has a uniform field geometry, is achieved by exploitation of the secondary light emission that occurs during gaseous multiplication. This light is focused onto, and detected by, an image intensifier tube which is itself viewed by an electronic image sensor array affording a genuinely 2-dimensional readout of the position of the avalanche initiated by an incident VUV photon or particle track. Efficient detection of single VUV photons has been achieved with a positional resolution of 260 μm in both dimensions. Given a more suitable image intensifier tube, this could be reduced to 100 μm or less for both VUV photons or particle tracks.