Temperature compensation circuit for silicon photomultipliers and other single photon counters

A method of making a radiation detector module comprising:

• forming an array of APDs;
• optically coupling sensor APDs with scintillators;
• optically shielding at least one reference APD;
• mounting the optically shielded at least one reference APD to the scintillator, the at least one reference APD being optically shielded from the scintillator;
• biasing the sensor and reference APDs to a breakdown region in a Gieger mode such that the sensor APDs breakdown in response to light from the scintillators and the at least one reference APD breaks down in response to a thermal generation of an electron-hole pair;
• quenching the sensor and reference APDs which break down such that the sensor APD generates a series of pulses indicative of light received from the scintillators and the least one reference APD generates a series of pulses indicative of temperature;
• connecting the optically shielded reference APD with a temperature compensation circuit which adjusts a bias voltage applied to the sensor APDs based on the series of pulses from the at least one reference APD.

A radiation detector module for use in radiation emission tomography, the detector module comprising:

• at least one monolithically disposed detector pixel, each detector pixel including a scintillator optically coupled to one or more sensor APDs that are biased in a breakdown region in a Geiger-mode and connected with quenching circuits, the sensor APDs being optically coupled to the scintillator and configured to output a current pulse in response to light from the scintillator corresponding to a single incident radiation photon;
• at least one monolithically disposed reference APD optically isolated from the scintillator, statically biased in a breakdown region in the Geiger mode, and configured with at least one quenching circuit to output a current pulse in response to each breakdown event triggered by a thermal generation of an electron-hole pair;
• at least one monolithically disposed temperature compensation circuit configured to determine a corrected voltage bias based on a rate of the thermally generated break down events;
• and
• at least one monolithically disposed variable voltage source configured to adjust the voltage bias applied to sensor APDs to apply the corrected voltage bias determined by the temperature compensation circuit.