Portable transfer digital dosemeter for beam output measurements with X and gamma rays, electrons and neutrons

The British Journal of Radiology
A SankaranP Gangadharan

Abstract

This instrument was developed in response to a requirement for an accurate, stable and portable transfer dosemeter for calibration, at therapy dose levels, of equipment used for generating X and gamma rays, electrons and neutrons. The detector is a 0.5 cm3 ionization chamber capable of fitting various wall materials reproducibly at the end of the chamber stem. The measuring system uniquely combines the features of a MOSFET electrometer and an automatic Townsend balance. When used for X, gamma and neutron radiations, the instrument measures the tissue kerma in free air on two ranges: 0.001 - 1.999 Gy (0.1 - 199.9 rad) and 0.01 - 19.99 Gy (1 - 1999 rad) or their exposure equivalents, with autoranging feature when the first range is exceeded. The polarizing voltage (180 V) can be reversed for electron and neutron dosimetry. The dosemeter has a measuring accuracy of +/- 0.2% FS +/- 1 digit and operates on four 1.5 V torchlight cells or on AC mains (200-250 V, 50 - 60 Hz). It utilizes solid state devices, CMOS integrated circuits and displays, and is not affected by RF fields. The instrument is enclosed in a brief-case for portability and is easy to operate and maintain in a hospital.

References

Mar 1, 1979·The British Journal of Radiology·J R WilliamsC J Parnell
Jul 1, 1975·Medical Physics·A R Smith, P R Almond
Apr 1, 1976·The International Journal of Applied Radiation and Isotopes·D Greene, J Miles
Oct 1, 1966·Physics in Medicine and Biology
Apr 1, 1969·The British Journal of Radiology·D K Bewley, C J Parnell
Mar 1, 1972·Physics in Medicine and Biology·E G Aird, F T Farmer
May 1, 1980·Physics in Medicine and Biology·A Sankaran, P Gangadharan

Related Concepts

Electronic
Fast Electrons
X-Rays, Nuclear
Neutrons
Nuclear Track Detection
Radiotherapy Dosage
Roentgen Rays

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