A form of gamma-ray detector. Similar to the ionization chamber in that a center rod electrode is maintained at a positive potential relative to the cylindrical chamber wall. The difference is that the Geiger-Mueller tube chamber contains gas at a low pressure and maintains the center electrode at a high positive voltage (e.g., 900-l000 volts). Incident gamma rays cause the ejection of electrons from detector walls into the gas. As the ejected electron is drawn toward the highly charged center electrode, other collisions occur between each electron and gas atoms, thus producing additional electrons which in turn cause additional ionization by collision. That results in a multiplication of the ionization events, and an avalanche of electrons arrives at the central electrode. The surge of electrical current must be quenched before another surge can be determined. That results in a number of easily detectable pulses related to the number of gamma-ray interactions. Increased length and additional plates and baffles are used to increase the number of interactions by incident gamma rays. The increased length tends to decrease vertical resolution. Compare scintillation counter.
terms:geiger_mueller_counter
terms/geiger_mueller_counter.txt · Last modified: 2023/11/22 08:41 by 127.0.0.1