Performance of microstrip gas chambers in BNL-E885: a search for ΛΛ-hypernuclei

The performance of MicroStrip Gas Chambers (MSGC) in BNL Experiment 885, a search for ΛΛ-hypernuclei, is detailed. Chambers with an active area of 80×50 mm2 were instrumented and operated as a vertex detector in the experiment. Furthermore, two distinct types of microstrip prints were utilized in these chambers. Prints manufactured with Integrated Circuit (IC) photolithographic technology have fine tolerances and thin minimum trace widths, but can suffer from a high rate of defects per print and are more costly. Prints constructed with Printed Circuit (PC) photolithographic technology have coarser tolerances but relatively few defects per print, and are extremely cost-effective. Results of bench and beam tests of both IC and PC based MSGCs are presented and their performance in BNL-E885 is discussed. E885 marks the first use of PC based MSGCs in an experiment.