Characteristics of irradiated silicon microstrip detectors with ⟨1 0 0⟩ and ⟨1 1 1⟩ substrates

In a program of developing radiation-hard silicon sensors for the LHC-ATLAS experiment. we have irradiated various types of silicon sensors with 12 GeV protons at KEK. Among the other properties, we made a comparative study of characteristics of the sensors with two wafer planes <1 1 1 > and <1 0 0 >. The studied sensors are p-on-n type, which satisfy the ATLAS-SCT specifications. Possible dependence on the substrate orientation could result from different dangling-bond configurations, The compared characteristics are the charge collection efficiency, interstrip capacitance, and noise levels. The noise levels were measured with a real ATLAS-SCT electronics system. A substantial difference is observed in the interstrip capacitance at similar to 10 kHz, while the difference is small at > 1 MHz, The differences in the charge collection efficiency and in the noise levels appear to be small. (C) 2001 Elsevier Science B.V. All rights reserved.