Operation of heavily irradiated silicon detectors under forward bias

Test diodes made of detector grade Si have been irradiated by fluences up to 2.8 × 1014 1 MeV neutrons per cm2. We observe that signals from minimum ionising particles are produced with high charge collection efficiency (CCE∼70%) at relatively low forward bias voltages. The more usual reverse bias requires ∼10 times larger voltage to produce similar CCE.