Apparatus comprising a semiconductor-based photomultiplier and method regarding gain stabilization
Apparatuses and methods as described herein can be used to help stabilize the gain of a semiconductor-based photomultiplier. In an embodiment, an apparatus can include a semiconductor-based photomultiplier. The apparatus can be configured to inject a first input pulse into the semiconductor-based photomultiplier; determine a revised bias voltage for the semiconductor-based photomultiplier based at least in part on a first output pulse corresponding to the first input pulse and a second output pulse from the semiconductor-based photomultiplier that is obtained at another time as compared to the first output pulse; and adjust a bias voltage for the semiconductor-based photomultiplier to the revised bias voltage. A calibration light source, a temperature sensor, and temperature information are not required to be used for the method.
1. An apparatus comprising a semiconductor-based photomultiplier, the apparatus being configured to:
inject a first input pulse into the semiconductor-based photomultiplier;
determine a revised bias voltage for the semiconductor-based photomultiplier based at least in part on a first output pulse corresponding to the first input pulse and a second output pulse from the semiconductor-based photomultiplier that is obtained at another time as compared to the first output pulse; and
adjust a bias voltage for the semiconductor-based photomultiplier to the revised bias voltage.
2. The apparatus of claim 1 , wherein the determination of the revised bias voltage is performed without any temperature information.
3. The apparatus of claim 1 , wherein the apparatus is further configured to analyze a set of bias voltages to monitor or determine a health of the apparatus.
4. The apparatus of claim 1 , wherein the apparatus further comprises a pulse injection circuit configured to inject the first input pulse into the semiconductor-based photomultiplier during normal operation of the apparatus.
5. The apparatus of claim 1 , wherein the apparatus further comprises a bias voltage supply circuit that is configured to provide a bias voltage to the semiconductor-based photomultiplier.
6. A method, comprising:
providing an apparatus comprising a semiconductor-based photomultiplier;
injecting a first input pulse into the semiconductor-based photomultiplier;
determining a revised bias voltage for the semiconductor-based photomultiplier based at least in part on a first output pulse corresponding to the first input pulse and a second output pulse from the semiconductor-based photomultiplier that is obtained at another time as compared to the first output pulse; and
adjusting a bias voltage for the semiconductor-based photomultiplier to the revised bias voltage.
7. The method of claim 6 , wherein determining the revised bias voltage is performed without a calibration light source or any temperature information for the semiconductor-based photomultiplier.
8. The method of claim 6 , further comprising integrating the first output pulse over time to obtain a first integrated signal.
9. The method of claim 8 , wherein a second integrated signal corresponds to the second output pulse.
10. The method of claim 9 , wherein determining the revised bias voltage comprises determining the revised bias voltage that is within 9% of V B1 , wherein:
V B1 =V B2 +N *( S 2 −S 1 )
V B1 is a bias voltage corresponding to the first output pulse,
V B2 is a bias voltage corresponding to the second output pulse,
N is a conversion factor,
S 1 is the first integrated signal; and
S 2 is the second integrated signal.
11. The method of claim 6 , further comprising analyzing a set of bias voltages to monitor or determine a health of the apparatus.
12. The method of claim 6 , wherein the semiconductor-based photomultiplier is a Si photomultiplier.
13. The method of claim 6 , wherein the apparatus further comprising a pulse injection circuit that is configured to inject the first input pulse into the semiconductor-based photomultiplier during normal operation of the apparatus.
14. The method of claim 6 , wherein the apparatus further comprising a bias voltage supply circuit that is configured to provide a bias voltage to the semiconductor-based photomultiplier.
15. The method of claim 6 , wherein the apparatus comprises a light source.
16. The method of claim 15 , wherein:
the light source is a luminescent material optically coupled to the semiconductor-based photomultiplier; and
the apparatus further comprises a temperature sensor adjacent to an interface between the luminescent material and the semiconductor-based photomultiplier.
17. The method claim 6 , wherein temperature information is used as a coarse adjustment for the revised bias voltage, and the first input pulse is used as a fine adjustment for the revised bias voltage.
18. A method comprising:
providing an apparatus comprising a semiconductor-based photomultiplier;
injecting a first input pulse into the semiconductor-based photomultiplier;
determining a revised bias voltage for the semiconductor-based photomultiplier based at least in part on a first output pulse corresponding to the first input pulse and a second output pulse from the semiconductor-based photomultiplier that is obtained at another time as compared to the first output pulse, wherein determining the revised bias voltage comprises determining the revised bias voltage that is within 5% of V B1 , wherein:
V B1 =V B2 +N *( S 2 −S 1 )
V B1 is a bias voltage corresponding to the first output pulse,
V B2 is a bias voltage corresponding to the second output pulse,
N is a conversion factor,
S 1 is the first integrated signal; and
S 2 is the second integrated signal; and
adjusting a bias voltage for the semiconductor-based photomultiplier to the revised bias voltage.
19. The method of claim 18 , wherein determining the revised bias voltage comprises determining the revised bias voltage that is within 1% of V B1 .
20. The method of claim 18 , wherein a second integrated signal corresponds to the second output pulse.