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Commercial single-photon avalanche diode module for optical photons. A single-photon avalanche diode (SPAD), also called Geiger-mode avalanche photodiode [1] (G-APD or GM-APD [2]) is a solid-state photodetector within the same family as photodiodes and avalanche photodiodes (APDs), while also being fundamentally linked with basic diode behaviours.
Active and passive current-quenching techniques have been used for this purpose. SPADs that operate in this high-gain regime are sometimes referred to being in Geiger mode. This mode is particularly useful for single-photon detection, provided that the dark count event rate and afterpulsing probability are sufficiently low.
A Geiger counter (/ ˈ ɡ aɪ ɡ ər /, GY-gər; [1] also known as a Geiger–Müller counter or G-M counter) is an electronic instrument used for detecting and measuring ionizing radiation. It is widely used in applications such as radiation dosimetry , radiological protection , experimental physics and the nuclear industry .
Photon counting eliminates gain noise, where the proportionality constant between analog signal out and number of photons varies randomly. Thus, the excess noise factor of a photon-counting detector is unity, and the achievable signal-to-noise ratio for a fixed number of photons is generally higher than the same detector without photon counting.
Although the device works in digital/switching mode, most SiPMs are analog devices because the microcells are read in parallel, making it possible to generate signals with a dynamic range from a single photon to 1000 photons for a device with just a square-millimeter area.
The characteristic curve of Geiger–Müller tube response with constant radiation against varying tube voltage. The Geiger plateau is the voltage range in which the G-M tube operates in its correct mode, where ionization occurs along the length of the anode. If a G–M tube is exposed to a steady radiation source and the applied voltage is ...
Geiger Field, named for aviation pioneer Gen. Harold C. Geiger, ... Before 1965, the terminal building sat on the south side of the runways and United, Northwest and West Coast were the only ...
Geiger–Müller tubes are the primary components of Geiger counters. They operate at an even higher voltage, selected such that each ion pair creates an avalanche, but by the emission of UV photons, multiple avalanches are created which spread along the anode wire, and the adjacent gas volume ionizes from as little as a single ion pair event.