A Prototype Combination TPC Cherenkov Detector with GEM Readout for Tracking and Particle Identification and its Potential Use at an Electron Ion Collider

¹ Physics Department, Brookhaven National Laboratory, Upton, NY 11973 USA
² Physics Department, Yale University, New Haven, CT 06520 USA
³ Physics Department, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA

^a Corresponding author: woody@bnl.gov

Published online: 21 February 2018

Abstract

A prototype detector is being developed which combines the functions of a Time Projection Chamber for charged particle tracking and a Cherenkov detector for particle identification. The TPC consists of a 10×10×10 cm³ drift volume where the charge is drifted to a 10×10 cm² triple GEM detector. The charge is measured on a readout plane consisting of 2×10 mm² chevron pads which provide a spatial resolution ∼ 100 μm per point in the chevron direction along with dE/dx information. The Cherenkov portion of the detector consists of a second 10×10 cm² triple GEM with a photosensitive CsI photocathode on the top layer. This detector measures Cherenkov light produced in the drift gas of the TPC by high velocity particles which are above threshold. CF₄ or CF₄ mixtures will be used as the drift gas which are highly transparent to UV light and can provide excellent efficiency for detecting Cherenkov photons. The drift gas is also used as the operating gas for both GEM detectors. The prototype detector has been constructed and is currently being tested in the lab with sources and cosmic rays, and additional tests are planned in the future to study the detector in a test beam.