Systems and methods for detector output adjustment

Patent metadata

Field	Value
Publication number	US-10466368-B2
Application number	US-201715422833-A
Country	US
Kind code	B2
Filing date	Feb 2, 2017
Priority date	Feb 2, 2017
Publication date	Nov 5, 2019
Grant date	Nov 5, 2019

Abstract

A silicon photomultiplier (SiPM) based detection system includes a plurality of scintillators, SiPMs, a front end circuit, adjustment circuits, and an energy and position processing unit. The SiPMs have a non-linear response to energy deposition corresponding to radiation detection. The adjustment circuit is configured to receive an analog signal from SiPMs, and to provide an adjusted analog signal, which is configured to simulate a signal corresponding to a linear response. The energy and position processing unit utilizes the adjusted signal to provide energy and position information of detected events in the detector block.

First claim

What is claimed is:

1. A silicon photomultiplier (SiPM) based detection system comprising:
a plurality of scintillation crystals configured to detect radiation events, and to generate light photons responsive to deposited energy;
a plurality of SiPMs having a non-linear response, positioned in respect to one or more of the plurality of scintillation crystals to form a scintillation block and configured to provide an analog signal responsive to received light photons;
a front-end circuit including a plurality of buffer amplifiers, each buffer amplifier coupled to at least one respective SiPM and configured to relay signals from the at least one respective SiPM;
a plurality of adjustment circuits coupled to corresponding buffer amplifiers and SiPMs, each adjustment circuit configured to receive the analog signal from the corresponding SiPM via the front end circuit, and to adjust the received analog signal to provide an adjusted analog signal configured to simulate a signal from the corresponding SiPM corresponding to a linear response, wherein each of the plurality of adjustment circuits provides an accurate summed energy for events shared among at least some of the: plurality of scintillation crystals or plurality of scintillation detector blocks; and
an energy and position processing unit coupled to the plurality of adjustment circuits and configured to provide energy and position signals using the adjusted analog signals.

2. The detection system of claim 1 , further comprising a data acquisition unit coupled to the energy and position processing unit, and configured to receive the energy and position signals and to determine energy and position information using the energy and position signals.

3. The detection system of claim 2 , the data acquisition unit further comprising analog to digital converter (ADC) that is configured to digitize the energy and position signals from the energy and position processing unit, and provide digital energy and position information for data processing.

4. The detection system of claim 2 , wherein the energy and position information provides a total energy deposition of detected gamma ray or X-ray photon using adjusted analog signal.

5. The detection system of claim 2 , wherein the energy and position information provides at least a two-dimensional position of detected gamma rays or X-ray photons using the adjusted analog signal.

6. The detection system of claim 1 , wherein the analog signal comprises at least one of a current signal or a voltage signal.

7. The detection system of claim 1 , wherein the output signal of at least one of the SiPMs is a current signal, and a corresponding output signal of a corresponding buffer amplifier comprises at least one of a current signal or a voltage signal.

8. The detection system of claim 6 , wherein the adjustment circuit could be configured to provide a polynomial adjustment to a current signal provided by the corresponding buffer amplifier.

9. The detection system of claim 8 , wherein the adjustment circuit further comprises:
a current mirror configured to receive and copy the current signal and provide corresponding first and second copied signals;
a current squarer configured to receive the first copied signal and square the first copied signal to provide an amplified squared signal;
a current amplifier configured to receive the second copied signal and provide an amplified signal; and
a current summer configured to receive the amplified squared signal, the amplified signal, and an offset signal, and to combine the received signals to provide the adjusted analog signal.

10. The detection system of claim 6 , wherein the adjustment circuit is configured to provide an exponential adjustment to a current signal of the corresponding buffer amplifier.

11. The detection system of claim 1 , wherein the energy and position information based on adjusted analog signal is used to correct timing information of at least one of the radiation events.

12. The detection system of claim 1 , wherein the configuration of the adjustment circuit is determined based on a pixel-by-pixel based calibration process at various operational conditions.

13. The adjustment circuit of claim 12 , wherein the operational conditions comprise at least one of a SiPM device condition, an energy of detected gamma or X-ray photon, or crystal configuration.

14. The adjustment circuit of claim 13 , wherein the configuration of the adjustment circuit is real-time adjusted based on the operational conditions.

15. A method comprising:
detecting radiation events with scintillation crystals to generate light photons;
receiving the light photons with a silicon photomultiplier SiPM device having a non-linear response;
providing a SiPM signal responsive to receiving the light photons generated in response to the radiation events to an adjustment circuit via front end circuit;
adjusting, in an analog domain, the SiPM signal with the adjustment circuit to provide an adjusted analog signal configured to simulate a signal from the SiPM device corresponding to a linear response, wherein the adjusting comprises providing an accurate summed energy for events shared among at least some of a plurality of scintillation crystals;
providing an energy and position signal using the adjusted analog signal.

16. The method of claim 15 , further comprising digitizing the energy and position signal.

17. The method of claim 15 , wherein the SiPM signal is a current signal, and a corresponding output signal of the buffer amplifier is at least one of a current signal or voltage signal.

18. The method of claim 15 , wherein adjusting the analog signal comprises providing at least one of a polynomial adjustment or an exponential adjustment.

Assignees

• Gen Electric

Inventors

• Fu Geng
• Qian Hua
• Lai Hao
• Guo Jianjun
• Ivan Adrian
• Yanoff Brian

Classifications

• G01T1/208

  Circuits specially adapted for scintillation detectors, e.g. for the photo-multiplier section · CPC title

• G01T1/202 Primary

  the detector being a crystal · CPC title

• G01T1/2018 Primary

  Scintillation-photodiode combinations · CPC title

• G01T1/20184 Primary

  Detector read-out circuitry, e.g. for clearing of traps, compensating for traps or compensating for direct hits · CPC title