Abstracts Physics

The design, construction and calibration of a low-energy, low exposure-rate ionization chamber

by Arthur Porter Clarke

A low-energy, low-exposure-rate, guarded-field ionization chamber system with a sensitive volume of approximately 1040 cm³ and an exposure-rate range from 60 mR/h to less than 0.5 mR/h was designed, constructed and calibrated. The calibration was effected by constructing and calibrating a 60 cm³ volume transfer chamber of similar design against a Victoreen 415A Intercomparison Standard. The transfer chamber was then used to calibrate the 1040 cm³ chamber. The overall error of the calibration was estimated to be less than ± 4%. The linearity of the chamber over the energy range of 7.5 to 40 keV was ± 1.45%.