Patent ID: 7800071

Claim:
A method of reducing polarization in a photon counting CdZnTe (CZT) pixilated detector including at least one monolithic semiconductor plate having a monolithic cathode electrode and a pixilated anode with electrodes coupled thereto, wherein the semiconductor plate comprises a trap level having an energy level between a valence band and a conduction band of the semiconductor plate, wherein, in response to absorption of ionizing high flux X-ray radiation in the semiconductor plate, the pixilated detector generates an electrical signal in the anode electrodes by electron motion towards the anodes, wherein the absorption of the high flux X-ray radiation creates an inhomogeneous positive space charge in the semiconductor plate, wherein the inhomogeneous positive space charge produces a polarization effect in the semiconductor plate by an attraction of electrons to the cathode electrode, and wherein the polarization effect causes a reduction in the electron motion towards the anode electrodes, thereby reducing the electrical signal generated in the anode electrodes, the method including: optically coupling into the semiconductor plate infra-red (IR) radiation of one or more wavelengths, to which the semiconductor plate is at least partially transparent, such that the IR radiation is to ionize the trap level so as to generate trapped positive charges in the semiconductor plate and to homogenize the positive space charge by producing a substantially uniform space charge over substantially the entirety of the semiconductor plate, and so as to reduce the polarization and the attraction of the electrons to the cathode electrode by the inhomogeneous space charge, thereby to improve a drift of the electrons toward the anode electrode.