Investigation of the radiation damage of GaAs detectors by protons, pions and neutrons

• 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.383-389
• Main Authors: Tenbusch, F, Arbabi, S, Braunschweig, W, Chu, Z, Krais, R, Kubicki, Th, Lübelsmeyer, K, Rente, C, Syben, O, Toporowski, M, Wittmer, B, Xiao, W.J
• Format: Article
• Language: English
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/S0168-9002(96)01261-2

Surface barrier detectors processed in Aachen using SI-GaAs from several manufacturers have been irradiated with high fluences of neutrons (mean energy 1 MeV, fluence up to Φ n ∼ 5 × 10 14cm −2), pions (191 MeV, fluence up to Φ π ∼ 0.6 × 10 14cm −2) and protons (23 GeV, fluence up to Φ p ∼ 2 × 10 14cm −2). The detectors have been characterized in terms of macroscopic quantities like I- V characteristic curves and charge collection efficiencies for incident minimum ionizing- (mip) as well as α-particles. All detectors work well after the exposure. At the highest fluences a sizable degradation concerning the charge collection efficiencies has been observed for all investigated materials. SI-GaAs material with low carbon content (LC material from FCM, Freiberg) seems to be less affected than substrates with a higher carbon concentration. At the highest irradiation level the mip signal from a 250 μm thick detector made of LC material amounts to 8000 electrons (at 400 V bias voltage) independent of peaking times between 40 ns and 2.2 μs. The leakage currents for this material are even reduced after the irradiation.