Field engineering by continuous hole injection in silicon detectors irradiated with neutrons

The electric field in irradiated silicon diodes was modified by manipulating the occupation of deep levels. This was achieved by continuous injection of holes using light illumination. Effective trapping probabilities and space-charge concentrations were measured in this operating mode. The bias voltage needed to establish the electric field in the whole detector volume, charge collection, power consumption and shot noise were investigated. The optimum operation point was found to be independent of irradiation fluence, providing a robust way of operating highly irradiated detectors, even if irradiated in a non-uniform way.