Measurements of possible type inversion in silicon junction detectors by fast neutron irradiation

The successful application of silicon position sensitive detectors in experiments at the SSC or LHC depends on an accurate assessment of the radiation tolerance of this detector species. In particular, fast neutrons (Eav = 1 MeV) produce bulk displacement damage that is projected, from estimated fluences, to cause increased generation (leakage) current, charge collection deficiencies, resistivity changes and possibly semiconductor type change or inversion. Whereas the leakage current increase was believed to be the major concern for estimated fluences of 1012 n/cm2 experiment year at the initial SSC luminosity of 1033/cm2-sec, increased luminosity and exposure time has raised the possible exposure to 1014 n/cm2, which opens the door for the several other radiation effects suggested above to play observable and significant roles in detector degradation or change. 17 refs., 19 figs