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BREAKDOWN VOLTAGE (Vbr) OR GAIN ADJUSTMENT AT SUB-PIXEL BUFFER FOR TEMPERATURE COMPENSATION AND CONTROL

IP.com Disclosure Number: IPCOM000248335D
Publication Date: 2016-Nov-16

Publishing Venue

The IP.com Prior Art Database

Abstract

A technique for compensating and controlling temperature of a solid state photomultiplier (SSPM) is disclosed. The technique includes an imaging detector system and method for controlling temperature of a solid state photomultiplier (SSPM). The imaging detector system includes a detector having a solid state photomultipler and a temperature control module. The solid state photomultiplier includes a plurality of microcells. The microcells output a signal indicative of a temperature of the solid state photomultiplier. The temperature control module is communicatively coupled to one or more than one microcell. The temperature control module provides a control signal to adjust at least one operating parameter of the detector. The method for controlling a temperature of an imaging system detector includes biasing a microcell of a plurality of microcells of a solid state photomultiplier, providing a signal from the microcell to control circuit, wherein the signal is indicative of a temperature of the solid state photomultiplier and adjusting at least one parameter based on the signal provided from the microcell.

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BREAKDOWN VOLTAGE (Vbr) OR GAIN ADJUSTMENT AT SUB-PIXEL BUFFER FOR TEMPERATURE COMPENSATION AND CONTROL

BACKGROUND

The present invention relates generally to an imaging detector system and more particularly to a technique for adjusting gain or breakdown voltage (Vbr) for compensation and control of temperature at sub-pixel buffer.

Generally, imagining technologies include one or more detectors configured to convert incident radiation to electrical signals that may be utilized for image formation.  Such detectors employ solid state photomultipliers (SSPM), for example silicon photomultipliers (SiPM), for detecting optical signals generated in a scintillator in response to an incident radiation. 

In detector systems, temperature variations of a SiPM device have a negative impact on overall detector performance and image quality.  For example, due to sensitivity of breakdown voltage (Vbr) and dark count rate to temperature, changes in temperature results in variations in baseline of dark current and device gain, thereby, degrading timing and/or energy resolution.  Such variations in temperature may be due to reasons, for example, heat dissipation of the SiPM device, non-uniform system cooling, and other environment changes, such as, magnetic field fluctuations. 

A conventional SiPM based detector system utilizes cooling systems that rely on thermocouples. The thermocouples are coupled to a package of SiPM devices to monitor temperature of the SiPM device.  However, such indirect measurements of temperature are typically inefficient and/or inaccurate and do not allow for real time monitoring and control. 

Therefore, it would be desirable to have a technique for controlling temperature of the solid state photomultiplier.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 is a diagrammatical representation of an exemplary PET imaging system in accordance with some aspects of the proposed technique.

Figure 2 depicts a block diagram representing one example of front-end readout electronics of a PET data acquisition system 230, such as may be used with the PET system 110 of Figure 1.

Figure 3 depicts a single SiPM, 240.

Figure 4 depicts a side view of a SiPM based detector assembly 400.

Figure 5 depicts a SiPM based detector system.

Figure 6 depicts the disclosed detector system 600.

Figure 7 depicts block diagram of the detector 600.

Figure 8 depicts a flowchart describing a method 800 for controlling a temperature of a detector in accordance with an embodiment of the disclosed technique.

DETAILED DESCRIPTION

A technique for compensating and controlling temperature of a solid state photomultiplier (SSPM) is disclosed. The technique includes an imaging detector system and method for controlling temperature of a solid state photomultiplier (SSPM). The imaging detector system includes a detector having a solid state photomultipler and a temperature control module. The solid state photomultiplier includes a plurality of microcells. The microcells output a sig...