Measurements on GaAs strip and pixel detectors in a 50 GeV pion beam

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Accelerators, spectrometers, detectors and associated equipment, 1997-04, Vol.388 (3), p.408-411
• Main Authors: Syben, O, Arbabi, S, Braunschweig, W, Breibach, J, Chu, Z, Karpinski, W, Krais, R, Kubicki, Th, Lübelsmeyer, K, Rente, C, Siedling, R, Tenbusch, F, Toporowski, M, Wittmer, B, Xiao, W.J
• Format: Article
• Language: English
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/S0168-9002(96)01259-4

GaAs strip and pixel detectors constructed in Aachen have been tested at CERN in a 50 GeV pion beam in September 1995 in collaboration with the CMS Tracker group. The strip detectors had a pitch of 100 μm and were made of a 250 μm thick Freiberger SI-GaAs wafer [1]. The three strip detectors had a strip width of 25, 50 and 75 μm, respectively. Using the fast PreMux128 preamplifier multiplexer chip ( τ p = 50 ns) a signal to noise ratio of 15 was obtained for the widest strips at normal beam incidence for a bias voltage of 170V. The 8 × 8 pixel arrays with a pixel size of 1 × 1 mm 2 and 0.5 × 0.5 mm 2, respectively, were read out with the PreMux128 as well. Here a signal of 12500e − was obtained for both detectors, leading to a maximum signal to noise ratio of 20 at perpendicular beam incidence and 170 V bias voltage.