Radiation Dosimeters Detect The Dose Absorbed By External Ionising Radiation
Dosimeters based on metal-oxide-semiconductor field-effect transistors are being employed as clinical Dosimeters for radiotherapy radiation beams. The following are the primary benefits of MOSFET devices:
1. The MOSFET dosimeter is a direct reading device with a small active area (less than 2m).
2. When packed, the MOSFET has a physical dimension of less than 4 mm.
3. The post-radiation signal is preserved indefinitely and is dose rate independent.
MOSFET gate oxide, which is commonly silicon dioxide, is used as an active sensing material in MOSFET Dosimeters. Radiation causes defects (electronic-hole pairs) in the oxide, which influences the MOSFET's threshold voltage.
The change in threshold voltage is proportional to the dosage of radiation. Alternative high-k gate dielectrics for radiation Dosimeters include hafnium dioxide and aluminium oxides. When heated, a thermo luminescent dosimeter monitors the intensity of light emitted from a Dy or B doped crystal in the detector. The amount of light emitted is proportional to the amount of radiation emitted.
These were once sold surplus, and one format used by submariners and nuclear workers resembled a dark green wristwatch containing the active components and a highly sensitive IR wire ended diode mounted to the doped LiF2 glass chip, which emits the stored radiation as narrow band infrared light when the assembly is precisely heated (hence thermo luminescent) until it is depleted. The key benefit is that the chip quietly records dose until exposed to light or heat, thus even a used sample stored in darkness can offer useful scientific data.
Read More - https://latesthighlightscmi.blogspot.com/2023/04/Dosimeters-necessary-tool-for-those-who.html
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