A photomultiplier is a device that converts incident photons into an

electrical signal In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The '' IEEE Transactions on Signal Processing' ...

. Kinds of photomultiplier include: * Photomultiplier tube, a

vacuum tube A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric voltage, potential difference has been applied. The type kn ...

converting incident photons into an electric signal. Photomultiplier tubes (PMTs for short) are members of the class of

s, and more specifically vacuum phototubes, which are extremely sensitive detectors of light in the

ultraviolet Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiati ...

, visible, and

near-infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...

ranges of the

electromagnetic spectrum The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies. The electromagnetic spectrum covers electromagnetic waves with frequencies ranging from ...

. ** Magnetic photomultiplier, developed by the Soviets in the 1930s. ** Electrostatic photomultiplier, a kind of photomultiplier tube demonstrated by

Jan Rajchman Jan Aleksander Rajchman ( London, 10 August 1911 – 1 April 1989) was a Polish electrical engineer and computer pioneer. Biography Jan Aleksander was son of Ludwik Rajchman and Maria Bojańczyk. His father was a Polish bacteriologist and ...

of RCA Laboratories in Princeton, NJ in the late 1930s which became the standard for all future commercial photomultipliers. The first mass-produced photomultiplier, the Type 931, was of this design and is still commercially produced today. * Silicon photomultiplier, a solid-state device converting incident photons into an electric signal. Silicon photomultipliers, often called "SiPM" in the literature, are

solid-state Solid state, or solid matter, is one of the four fundamental states of matter. Solid state may also refer to: Electronics * Solid-state electronics, circuits built of solid materials * Solid state ionics, study of ionic conductors and their ...

single-

photon A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are Massless particle, massless ...

-sensitive devices based on Single-photon avalanche diode (SPAD) implemented on common silicon substrate.Silicon Photom ultiplier Technology at STMicroelectronics From SPAD to SiPM
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References

{{SIA * Particle detectors