Radiation Detectors
• Mica window • Low pressure gas • High voltage • Anode/cathode • High E field • Massive ionization • Electron avalanche • Pulse
• It detects individual radiation particles or photons; • It can be connected directly to a counter; • Radiation enters the tube through the thin mica window (good for α – particles), and ionizes the low pressure gas, e.g. air or argon; • Electricity conduction is improved at low pressure; • The free electrons are accelerated towards the anode by the high voltage producing more ionizations and free electrons; • An avalanche of electrons arrives at the anode, which is detected as a voltage pulse that can be counted electronically.
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