A Description of the Jetset Barrel Gamma Veto

Abstract

In its phase-I implementation, the photon coverage in the Radphi experiment is confined to angles forward of 40^o in the lab. These forward angles are the most important for reconstructing the final states of interest to this experiment. However our lack of knowledge about what photons were produced at larger angles has an important effect on our ability to reject background events in our sample. Discussion is underway with David Hertzog at the University of Illinois concerning the possible loan of the barrel gamma veto (BGV) spaghetti calorimeter modules from the Jetset experiment at LEAR for use as a photon multiplicity counter in the Radphi experiment. In addition to providing a veto on events with large-angle photons, it could also provide medium-resolution calorimetry for low-energy showers. In combination with a barrel scintillator array (barrel CPV) it could also provide information on the number and angles of charged-particle tracks. This report summarises the design and features of the BGV, and shows some of the data from the Jetset experiment which give an indication of its performance. Many of the figures contained in this report are taken from the thesis of Johannes Ritter.