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The proportional counter is a type of gaseous ionization detector device used to measure particles of ionizing radiation.The key feature is its ability to measure the energy of incident radiation, by producing a detector output pulse that is proportional to the radiation energy absorbed by the detector due to an ionizing event; hence the detector's name.
A Coulter counter [1] [2] is an apparatus for counting and sizing particles suspended in electrolytes. The Coulter counter is the commercial term for the technique known as resistive pulse sensing or electrical zone sensing. The apparatus is based on the Coulter principle named after its inventor, Wallace H. Coulter.
A wire chamber or multi-wire proportional chamber is a type of proportional counter that detects charged particles and photons and can give positional information on their trajectory, [1] by tracking the trails of gaseous ionization. [2]
The first commercial liquid scintillation counter was made by Lyle E. Packard and sold to Argonne Cancer Research Hospital at the University of Chicago in 1953. The production model was designed especially for tritium and carbon-14 which were used in metabolic studies in vivo and in vitro .
The D'Hondt method, [a] also called the Jefferson method or the greatest divisors method, is an apportionment method for allocating seats in parliaments among federal states, or in proportional representation among political parties.
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.
A complete Geiger counter, with the Geiger–Müller tube mounted in a cylindrical enclosure connected by a cable to the instrument. The Geiger–Müller tube or G–M tube is the sensing element of the Geiger counter instrument used for the detection of ionizing radiation.
Most frequency counters work by using a counter, which accumulates the number of events occurring within a specific period of time.After a preset period known as the gate time (1 second, for example), the value in the counter is transferred to a display, and the counter is reset to zero.