Patent ID: 8426827

Claim:
A detector, comprising: a first scintillation material having a light yield temperature dependence and an output responsive to radiation emitted from an ionizing radiation source, the output of the first scintillation material being at a first energy level; a second scintillation material having a light yield temperature dependence similar to the first scintillation material and an output responsive to radiation emitted from an ionizing radiation source, the output of the second scintillation material being at a second energy level different than the first energy level; and detection circuitry including: a photo multiplier tube configured to convert photon outputs from the first and second scintillating materials to electrical pulses; a counter circuit configured to count the electrical pulses generated in the photo multiplier tube by the first and second scintillation materials; and a gain control circuit configured to monitor the electrical pulses generated in the photomultiplier tube by the second scintillation material that exceed those of the first scintillation material and further configured to adjust a gain of the detector upon detecting a drift in the output of the second scintillation material.