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Sensors and Transducers
Published in David C. Swanson, ®, 2011
To breakdown the particle events according to their respective energy levels, a proportional counter is made by lowering the plate voltage and optimizing the gas mixture so that the collected charge is proportional to the energy of the particle. This type of detector has multiple “channels” or bands of energy where the number of particle events in each band is tallied independently making it useful for measuring x-rays and γ-rays separately. Another version of this is the scintillation counter, where a crystal or gas fluoresces to produce detectable photons that are proportional to the particle energy. These photons are generally quite weak, so the signal needs to be amplified using a phosphor to convert the photons to electrons, and then an electron multiplier tube to boost up the number of electrons for charge detection. A charge amplifier completes the system to produce a reasonable voltage proportional to the particle energy. These types of counter have a limited number of energy bands, or channels as they are called, allowing the relative energies to be estimated. However, the charge integration/amplification time is vulnerable to multiple particles “piling up” to be mistaken as a single, much higher energy particle, so this type of detector can be in error in high radiation fields.
Radiation Detection and Measurement
Published in Shaheen A. Dewji, Nolan E. Hertel, Advanced Radiation Protection Dosimetry, 2019
A proportional counter is essentially an ionization chamber, operated at a higher potential, wherein pulses are detected rather than charge measured. Pulse heights produced in an ionization chamber are small, but when the potential is increased, there is a region of operation where pulse heights increase with applied potential. This type of operation can provide additional information that is useful for characterizing the radiation being measured (Knoll 2010).
Ionizing Radiation
Published in David M. Scott, Industrial Process Sensors, 2018
Normally the avalanche produced in the tube gives a pulse that is independent of the energy of the incident radiation, but under certain conditions the pulse is proportional in height to the energy. This type of gas-filled detector is called a proportional counter.
Radiation Protection at Petawatt Laser-Driven Accelerator Facilities: The ELI Beamlines Case
Published in Nuclear Science and Engineering, 2023
Anna Cimmino, Veronika Olšovcová, Roberto Versaci, Dávid Horváth, Benoit Lefebvre, Andrea Tsinganis, Vojtěch Stránský, Roman Truneček, Zuzana Trunečková
Prompt gamma and neutron dose rates are measured in the high-occupancy areas (control rooms) or regularly accessed areas (corridors). A combined novel monitor for pulsed radiation, the LB-6419 (Refs. 63, 64, and 65) is used. It comprises a helium-based proportional counter for neutron detection and a plastic scintillator for beta and gamma detection. Also, the characteristics of the radiation field in some locations has allowed for the installation of photon detectors only. A wide-range pressurized ionization chamber66 was selected for this purpose.