Construction and expected performance of the hadron blind detector for the PHENIX experiment at RHIC

Abstract

A new hadron blind detector (HBD) for electron identification in high density hadron environment has been installed in the PHENIX experiment at RHIC in the fall of 2006. The HBD will identify low momentum electron–positron pairs to reduce the combinatorial background in the e+e− mass spectrum, mainly in the region below 1 GeV/c2. The HBD is a windowless proximity-focusing Cherenkov detector with a radiator length of 50 cm, a CsI photocathode and three layers of gas electron multipliers (GEM). Pure CF4 is used as a radiator and a detector gas. This proceeding describes the construction details and the expected performance of the HBD.