Silicon photomultipliers with internal calibration circuitry

Patent metadata

Field	Value
Publication number	US-2016182902-A1
Application number	US-201414574836-A
Country	US
Kind code	A1
Filing date	Dec 18, 2014
Priority date	Dec 18, 2014
Publication date	Jun 23, 2016
Grant date	—

Abstract

A silicon photomultiplier includes a plurality of microcells providing a pulse output in response to an incident radiation, each microcell including circuitry configured to enable and disable the pulse output. Each microcell includes a cell disable switch. The control logic circuit controls the cell disable switch and a self-test circuit. A microcell's pulse output is disabled when the cell disable switch is in a first state. A method for self-test calibration of microcells includes providing a test enable signal to the microcells, integrating dark current for a predetermined time period, comparing the integrated dark current to a predetermined threshold level, and providing a signal if above the predetermined threshold level.

First claim

1 . A silicon photomultiplier array comprising:
a plurality of microcells each providing a pulse output in response to an incident radiation, each microcell including circuitry configured to enable and disable the pulse output; each of the plurality of microcells including a cell disable switch and a self-test circuit; and wherein the pulse output is disabled when the cell disable switch is in a first state.

2 . The silicon photomultiplier array of claim 1 , including:
a row counter connected to a predefined row among the plurality of microcells, and configured to count a latch signal output of each microcell of the predefined row; a pixel controller connected to the row counter, the pixel controller configured to provide a signal to a control logic circuit of each of the plurality of microcells; and the row counter providing a dark count high indication signal to the pixel controller.

3 . The silicon photomultiplier array of claim 2 , the pixel controller configured to monitor the dark count high indication signal and, if the dark count high indication is below a predetermined threshold of inhibited microcells, provide an inhibit signal to the plurality of microcells.

4 . The silicon photomultiplier array of claim 3 , the pixel controller configured to remove the inhibit signal if the dark count high indication is above a predetermined number of inhibited microcells.

5 . The silicon photomultiplier array of claim 1 , a control logic circuit providing a configure cell signal to components of its respective microcell.

6 . The silicon photomultiplier array of claim 5 , the configure cell signal operative to cause a change in a comparator threshold voltage reference of the respective microcell.

7 . The silicon photomultiplier array of claim 1 , each of the plurality of microcells including:
an avalanche photodiode having an anode terminal and a cathode terminal; a first operational amplifier having an output terminal, a first input terminal in electrical communication with the cathode terminal and a second input terminal connected to a reference voltage level; a second operational amplifier having an input in electrical communication with the first operational amplifier output, the second operational amplifier having another input connected to a threshold voltage and an output in electrical communication with a one shot pulse circuit; a one shot pulse circuit configured to generate the pulse output; and a latch circuit in electrical communication with the second operational amplifier output.

8 . The silicon photomultiplier array of claim 7 , the first operational amplifier configured as a current sense amplifier.

9 . The silicon photomultiplier array of claim 7 , including a quenching circuit connected in series with the cathode terminal.

10 . The silicon photomultiplier array of claim 1 , including a pixel summer connected to the pulse output of each of the plurality of microcells.

11 . The silicon photomultiplier array of claim 1 , including the self-test circuit configured to provide a latch signal in response to a self-test operation.

12 . The silicon photomultiplier array of claim 11 , including the control logic circuit configured to provide a control signal to the cell disable switch based on a pixel controller signal and a signal provided by the latch circuit, the control signal causing the cell disable switch to change between two states.

13 . A method for self-test calibration of a respective microcell in a silicon photomultiplier array including a plurality of microcells, the method comprising:
providing a test enable signal from a pixel controller to the plurality of microcells to place each of the plurality of microcells in a self-test mode; integrating dark current generated by an avalanche photodiode within the respective microcell for a predetermined time period; comparing the integrated dark current of the respective microcell to a predetermined threshold level; and if the integrated dark current of the respective microcell is above the predetermined threshold level, providing a dark current high signal to the pixel controller.

14 . The method of claim 13 , including performing the dark current integration by an operational amplifier configured as a charge sense amplifier.

15 . The method of claim 13 , including adjusting the integration predetermined time period under control of the pixel controller.

16 . The method of claim 13 , including performing the self-test at power-on of the silicon photomultiplier array.

17 . The method of claim 13 , including disabling the respective microcell if the integrated dark count is above the predetermined threshold.

18 . The method of claim 17 , including:
quantifying a number of disabled respective microcells; and inhibiting the self-test if the number is above a predetermined quantity of disabled respective microcells.

19 . The method of claim 13 , including configuring the respective microcell into a self-test mode by changing a state of a switch within the respective microcell.

20 . The method of claim 19 , including providing a latch signal to change the switch state from a self-test circuit within the respective microcell.

Assignees

• Gen Electric

Inventors

• Guo Jianjun
• Dolinsky Sergei Ivanovich

Classifications

• G01T1/248

  Silicon photomultipliers [SiPM], e.g. an avalanche photodiode [APD] array on a common Si substrate · CPC title

• G01T1/208

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

• H04N17/002 Primary

  for television cameras · CPC title

• H04N5/341

  Electricity · mapped topic

• H04N25/773

  comprising photon counting circuits, e.g. single photon detection [SPD] or single photon avalanche diodes [SPAD] · CPC title