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. A semiconductor is a material with an electrical conductivity between that of a conductor and an insulator. The electrical conductivity of a substance measures how much electric current flows when a given electrical potential is placed across it. A perfect insulator has an electrical conductivity of 0, indicating that no current flows through it even when an electrical difference is present. A semiconductor normaly acts like an insulator up to certain potential difference, called the breakdwon voltage, above which it becomes conducting.  

Silicon photomultipliers use semiconductor technology to detect single photons at room temperature. A semiconductor is a material with an electrical conductivity between that of a conductor and an insulator. The electrical conductivity of a substance measures how much electric current flows when a given electrical potential is placed across it. A perfect insulator has an electrical conductivity of 0, indicating that no current flows through it even when an electrical difference is present. A semiconductor normally acts like an insulator up to certain potential difference, called the breakdown voltage, above which it becomes conducting.  

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.  

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.