Author/Authors :
Lübelsmeyer، نويسنده , , K. and Arbabi، نويسنده , , S. and Braunschweig، نويسنده , , W. and Chu، نويسنده , , Z. and Krais، نويسنده , , David R. and Kubicki، نويسنده , , Th. and Rente، نويسنده , , C. and Syben، نويسنده , , O. and Tenbusch، نويسنده , , F. and Toporowski، نويسنده , , M. and Wittmer، نويسنده , , B. and Xiao، نويسنده , , W.J.، نويسنده ,
Abstract :
Surface barrier detectors processed in Aachen using semi-insulating (SI) GaAs from several manufacturers have been irradiated with high fluences of neutrons (mean energy 1 MeV, fluence up to Φn ∼ 5 × 1014 cm−2), pions (191 MeV, fluence up to Φπ ∼ 0.6 × 1014 cm−2) and protons (23 GeV, fluence up to Φp ∼ 2 × 1014 cm−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 in the charge collection efficiencies has been observed for all investigated materials. SI-GaAs material with low carbon (LC) content 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.
