Position sensitive solid-state photomultipliers, systems and methods

• US 8,884,240 B1
• Filed: 10/15/2009
• Issued: 11/11/2014
• Est. Priority Date: 06/08/2009
• Status: Active Grant

• Current Assignee: Radiation Monitoring Devices, Inc. (Dynasil Corp. of America)
• Original Assignee: Radiation Monitoring Devices, Inc. (Dynasil Corp. of America)
• Inventors: Shah, Kanai S., Christian, James, Stapels, Christopher, Dokhale, Purushottam, McClish, Mickel
• Primary Examiner(s): Porta, David
• Assistant Examiner(s): LEE, SHUN K
• Application Number:
  US12/580,172
• Time in Patent Office: 1,853 Days
• Field of Search: 250/363.05, 250/370.11, 250/370.14
• US Class Current: 250/370.14
• CPC Class Codes: G01R 33/481 MR combined with positron emission tomography [PET] or single photon emission computed tomography [SPECT]
• CPC Class Codes: G01T 1/1603 with a combination of at least two different types of detector see provisionally also G01T1/16
• CPC Class Codes: G01T 1/18 with counting-tube arrangements, e.g. with Geiger counters tubes H01J47/08; with alarm provision G01T7/125
• CPC Class Codes: G01T 1/20184 Detector read-out circuitry, e.g. for clearing of traps, compensating for traps or compensating for direct hits
• CPC Class Codes: G01T 1/20185 Coupling means between the photodiode and the scintillator, e.g. optical couplings using adhesives with wavelength-shifting fibres
• CPC Class Codes: G01T 1/208 Circuits specially adapted for scintillation detectors, e.g. for the photo-multiplier section
• CPC Class Codes: G01T 1/248 Silicon photomultipliers [SiPM], e.g. an avalanche photodiode [APD] array on a common Si substrate
• CPC Class Codes: G01T 1/249 specially adapted for use in SPECT or PET SPECT imaging G01T1/1642; PET imaging G01T1/2985; detecting prohibited goods, e.g. weapons, explosives, hazardous substances, contraband or smuggled objects G01V5/20
• CPC Class Codes: G01T 1/2985 In depth localisation, e.g. using positron emitters; Tomographic imaging (longitudinal and transverse section imaging; apparatus for radiation diagnosis sequentially in different planes, steroscopic radiation diagnosis); using external radiation sources A61B6/02

Abstract

An integrated silicon solid state photomultiplier (SSPM) device includes a pixel unit including an array of more than 2×2 p-n photodiodes on a common substrate, a signal division network electrically connected to each photodiode, where the signal division network includes four output connections, a signal output measurement unit, a processing unit configured to identify the photodiode generating a signal or a center of mass of photodiodes generating a signal, and a global receiving unit.

Claims

1. An integrated silicon solid state photomultiplier (SSPM) device operable in a Geiger mode, the device comprising:

a pixel unit including an array of more than 2×

2 p-n micro-pixels on a common substrate;

a signal division network electrically coupled to each micro-pixel, the signal division network including four output connections each for providing an output signal;

a signal output measurement unit configured to measure the output signal from each output connection;

a processing unit configured to process the output signals so as to identify the micro-pixel generating a signal or a center of mass of micro-pixels generating a signal, and

a global signal receiving unit comprising a preamplifier electrically coupled in series with a capacitor, wherein the capacitor is electrically coupled to the micro-pixels,

wherein the signal division network further includes a plurality of resistive elements;

the micro-pixels are arranged in a plurality of rows and columns;

the micro-pixels arranged in the same row are coupled in parallel with one another;

the micro-pixels arranged in the same column are coupled in parallel with one another;

one of the plurality of resistive elements is provided, for each row of micro-pixels, in series between the micro-pixels in the same row and the micro-pixels in an adjacent row; and

one of the plurality of resistive elements is provided, for each column of micro-pixels, in series between the micro-pixels in the same column and the micro-pixels in an adjacent column.

2. The device of claim 1, wherein a drain voltage is applied to each micro-pixel.

3. The device of claim 2, wherein each micro-pixel further includes a pair of transistors, and a gate of each transistor is electrically coupled to the resistive element.

4. An integrated silicon solid state photomultiplier (SSPM) device operable in a Geiger mode, the device comprising:

a pixel unit including an array of more than 2×

2 p-n micro-pixels on a common substrate;

a signal division network electrically coupled to each micro-pixel, the signal division network including four output connections each for providing an output signal;

a signal output measurement unit configured to measure the output signal from each output connection;

a processing unit configured to process the output signals so as to identify the micro-pixel generating a signal or a center of mass of micro-pixels generating a signal, and

a global signal receiving unit comprising a preamplifier electrically coupled in series with a capacitor, wherein the capacitor is electrically coupled to the micro-pixels,

wherein the signal division network further includes a plurality of resistive elements;

the micro-pixels are arranged in a plurality of rows;

the micro-pixels arranged in the same row are coupled in parallel with one another and are each coupled in parallel with one of the plurality of resistive elements; and

one of the plurality of resistive elements is coupled in series between each pair of micro-pixels arranged in the same row.

5. The device of claim 4, wherein the signal output measurement unit includes a resistive element and a preamplifier electrically coupled to each of the four output connections.

6. A radiation detection system comprising:

the integrated silicon solid state photomultiplier (SSPM) device of claim 4; and

a scintillator optically coupled to the SSPM device.

7. The system of claim 6 wherein the scintillator comprises individual elements matched to the geometry of the integrated silicon SSPM.

8. The system of claim 6 wherein the scintillator comprises a pixellated microcolumnar scintillator.

9. The system of claim 6 wherein the scintillator comprises a substantially continuous scintillator.

10. A combined PET/MRI imaging system, comprising:

a main magnet for use in MRI imaging;

an RF coil disposed in the main magnet for use in MRI imaging; and

a PET scanner disposed between the main magnet and the RF coil for use in PET imaging, the PET scanner comprising the integrated silicon solid state photomultiplier device of claim 4.