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OPTICAL BUFFER LAYER FOR SILICON PHOTOMULTIPLIERS (Si-PM)

IP.com Disclosure Number: IPCOM000199447D
Publication Date: 2010-Sep-04
Document File: 4 page(s) / 23K

Publishing Venue

The IP.com Prior Art Database

Abstract

A technique proposing an optical buffer layer which maintains a uniform distribution of light out of a scintillator is disclosed. This technique proposes utilization of an optical buffer layer between the scintillator and silicon photomultipliers (Si-PM). By using the proposed technique high optimization of the silicon photomultipliers (Si-PM) device becomes possible.

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This is the abbreviated version, containing approximately 57% of the total text.

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RP13482

OPTICAL BUFFER LAYER FOR SILICON PHOTOMULTIPLIERS (Si-PM)

BRIEF ABSTRACT

    A technique proposing an optical buffer layer which maintains a uniform distribution of light out of a scintillator is disclosed. This technique proposes utilization of an optical buffer layer between the scintillator and silicon photomultipliers (Si-PM). By using the proposed technique high optimization of the silicon photomultipliers (Si-PM) device becomes possible.

KEYWORDS

    Silicon Photomultipliers (Si-PM), scintillator, avalanche photodiode (APD), photomultiplier tubes (PMT), sensor, optical buffer layer, photon, energy resolution.

DETAILED DESCRIPTION

    Generally, Silicon Photomultipliers (Si-PM) are Silicon single photon sensitive devices built from an avalanche photodiode (APD) array on a common Si substrate. Typically, Si-PM devices are used for detection of single photon events in sequentially connected Si APDs. Every APD in a Si-PM operates in Geiger mode and is coupled with other Si-PMs by a poly silicon quenching resistor. The Si-PM device works in digital or switching mode. However, Si-PM is an analog device since all microcells are read in parallel which makes it possible to generate signals within a dynamic range from a single photon to up to thousand photons for a single square millimeter area device. Supply voltage

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RP13482

depends on APD technology used and typically varies between 25 V and 70 V. This voltage is 30 to 50 times lower than the voltage required for traditional photomultiplier tubes (PMT) operation.

    Conventionally, a Si-PM is designed for a configuration where the light coming from a scintillator is uniformly distributed over the surface of a sensor. However, in a configuration where the scintillator is in intimate contact with the Si-PM, the scintillation event occurs close to the Si-PM surface. In such a situation, the light density is very high and results in a loss of energy resolution.

    There existsno known solution for the problem as Si-PM is a relatively new technology that is still being explored. The alternative to the Si-PM is a photomultiplier tube (PMT). PMTs are members of the class of vacuum tubes, and more specifically phototubes. PMTs are extremely sensitive detectors of light in the ultraviolet, visible, and near-infrared ranges of...