Changes

The standard technology for such detectors, originally developed for atomic and nuclear physics experiments, is based on the photomultiplier vacuum tube.  Particle physics experiments have relied on photomultiplier tubes for over 40 years.  Ever since the invention of the transistor, efforts have been made to create semiconductor-based photon detectors, but certain drawbacks have limited their use to a few niche applications.  Recently, however, progress has been made toward the goal of creating silicon-based detectors with single-photon sensitivity that can operate at room temperature.  These devices are called silicon photomultipliers.

The standard technology for such detectors, originally developed for atomic and nuclear physics experiments, is based on the photomultiplier vacuum tube.  Particle physics experiments have relied on photomultiplier tubes for over 40 years.  Ever since the invention of the transistor, efforts have been made to create semiconductor-based photon detectors, but certain drawbacks have limited their use to a few niche applications.  Recently, however, progress has been made toward the goal of creating silicon-based detectors with single-photon sensitivity that can operate at room temperature.  These devices are called silicon photomultipliers.

Silicon photomultipliers use semiconductor technology to detect single photons at room temperature. Semiconductors are solids that have a conductivity between that of conductors and insulators, and can be changed with the addition of different impurities. (Electrical conductivity is the ability for a substance to move electrons from one area to another. It is primarily determind by the band gap of a substance. The band gap is the distance that an electron must travel before it goes into the conduction band. Smaller band gaps would equal a higher electrical conductivity) Semiconductors can be used to detect single photons because of their sensitivity to electrical fields.  

Silicon photomultipliers use semiconductor technology to detect single photons at room temperature. A semiconductor is a material that has a conductivity between that of a conductor and an insulator. That conductivity can be changed with the addition of different impurities. (Electrical conductivity is the ability for a substance to move electrons from one area to another. It is primarily determind by the band gap of a substance. The band gap is the distance that an electron must travel before it goes into the conduction band. Smaller band gaps would equal a higher electrical conductivity) Semiconductors can be used to detect single photons because of their sensitivity to electrical fields.  

The vast majority of electrical devices today make use of semiconductors. One very common electrical component is called a diode. A diode is a device that allows electricity to flow one way, but not the other.

The vast majority of electrical devices today make use of semiconductors. One very common electrical component is called a diode. A diode is a device that allows electricity to flow one way, but not the other.