Silicon photomultipliers, often called "SiPM" in the literature, are Silicon

Silicon

Silicon is a chemical element with the symbol Si and atomic number 14. A tetravalent metalloid, it is less reactive than its chemical analog carbon, the nonmetal directly above it in the periodic table, but more reactive than germanium, the metalloid directly below it in the table...

 single photon

Photon

In physics, a photon is an elementary particle, the quantum of the electromagnetic interaction and the basic unit of light and all other forms of electromagnetic radiation. It is also the force carrier for the electromagnetic force...

 sensitive devices built from an avalanche photodiode

Avalanche photodiode

An avalanche photodiode is a highly sensitive semiconductor electronic device that exploits the photoelectric effect to convert light to electricity. APDs can be thought of as photodetectors that provide a built-in first stage of gain through avalanche multiplication. From a functional standpoint,...

 (APD) array on common Si

Si

Si, si, or SI may refer to :- Measurement, mathematics and science :* International System of Units , the modern international standard version of the metric system...

 substrate. The idea behind this device is the detection of single photon events in sequentially connected Si

Si

Si, si, or SI may refer to :- Measurement, mathematics and science :* International System of Units , the modern international standard version of the metric system...

 APDs. The dimension of each single APD can vary from 20 to 100 micrometres, and their density can be up to 1000 per square millimeter. Every APD in SiPM operates in Geiger-mode

Single-Photon Avalanche Diode

In optoelectronics the term Single-Photon Avalanche Diode identifies a class of solid-state photodetectors based on a reverse biased p-n junction in which a photo-generated carrier can trigger an avalanche current due to the impact ionization mechanism...

 and is coupled with the others by a polysilicon quenching resistor. Although the device works in digital/switching mode, the SiPM is an analog device

Analog device

Analog device is an apparatus that measures continuous information. The measured analog signal has an infinite number of possible values. The only limitation on resolution is the accuracy of the measuring device. Such apparatus operates with variables which are constituted by continuously measured...

 because all the microcells are read in parallel making it possible to generate signals within a dynamic range from a single photon

Photon

In physics, a photon is an elementary particle, the quantum of the electromagnetic interaction and the basic unit of light and all other forms of electromagnetic radiation. It is also the force carrier for the electromagnetic force...

 to 1000 photon

Photon

In physics, a photon is an elementary particle, the quantum of the electromagnetic interaction and the basic unit of light and all other forms of electromagnetic radiation. It is also the force carrier for the electromagnetic force...

s for just a single square millimeter area device. The supply voltage (Vb) depends on APD technology used, and typically varies between 25 V and 70 V, thus being from 30 to 50 times lower than the voltage required for a traditional photomultiplier tubes

Photomultiplier

Photomultiplier tubes , members of the class of vacuum tubes, and more specifically phototubes, are extremely sensitive detectors of light in the ultraviolet, visible, and near-infrared ranges of the electromagnetic spectrum...

  (PMT

PMT

PMT may refer to:* Parent Management Training* Photomultiplier tube, an extremely sensitive light detector* Program Map Table, program specific information in an MPEG transport stream* Place–manner–time*Post-glacial marine transgression*Pearl milk tea...

s) operation.
SiPM has been invented in Russia in Moscow Engineering Physics Institute [1 - 4]. This design idea was then used with some variations by SensL, Photonique, Hamamatsu, Voxtel Inc., STMicroelectronics and other companies (see the list of SiPM Manufacturers below).

Typical specs for a SiPM:

1. Total quantum efficiency is about 20%, being similar to a traditional PMT
   PMT
   PMT may refer to:* Parent Management Training* Photomultiplier tube, an extremely sensitive light detector* Program Map Table, program specific information in an MPEG transport stream* Place–manner–time*Post-glacial marine transgression*Pearl milk tea...
   
   
2. Gain (G) is also similar to a PMT
   PMT
   PMT may refer to:* Parent Management Training* Photomultiplier tube, an extremely sensitive light detector* Program Map Table, program specific information in an MPEG transport stream* Place–manner–time*Post-glacial marine transgression*Pearl milk tea...
   
    being approx. 10⁶.
3. G vs Vb dependence is linear, does not follow a power law
   Power law
   A power law is a special kind of mathematical relationship between two quantities. When the frequency of an event varies as a power of some attribute of that event , the frequency is said to follow a power law. For instance, the number of cities having a certain population size is found to vary...
   
    like in the case of PMT
   PMT
   PMT may refer to:* Parent Management Training* Photomultiplier tube, an extremely sensitive light detector* Program Map Table, program specific information in an MPEG transport stream* Place–manner–time*Post-glacial marine transgression*Pearl milk tea...
   
   s
4. Timing jitter is optimized to have a photon arrival time resolution of about 100 ps
5. Signal decay time is inversely proportional to square root of photoelectrons number within an excitation event
6. The signal parameters are practically independent on external magnetic fields, in contrary to vacuum PMT
   PMT
   PMT may refer to:* Parent Management Training* Photomultiplier tube, an extremely sensitive light detector* Program Map Table, program specific information in an MPEG transport stream* Place–manner–time*Post-glacial marine transgression*Pearl milk tea...
   
   s
7. Small dimensions permits extremely compact, light and robust mechanical design

External links

SiPM Manufacturers:

• SENSL http://sensl.com/products/silicon-photomultipliers/
• Photonique http://www.photonique.ch/Products_SSPM_main.html#1.0SSPMs
• Hamamatsu Hamamatsu SiPM Catalog
• Voxtel Voxtel Homepage
• Zecotek Photonics http://www.zecotek.com/503/1107/
• Amplification Technologies http://www.amplificationtechnologies.com/products.htm
• STMicroelectronics SiPM Consortium presentation http://arxiv.org/abs/0705.0672v1
• Radiation Monitoring Devices, Inc. http://www.rmdinc.com/research/ird1.html