A SMALL WRIST DOSIMETER FOR BETA AND GAMMA RADIATION (thesis)
The principles of ion chamber design are discussed, and a personnel dosimeter embodying them is described. The device is basically a parallel-plate ionization chamber with closely spaced circular electrodes and may be worn conveniently anywhere on the body. The sensitive volume and capacitance of the chamber are chosen to permit charging and reading with Victoreen Minometers. The chamber has x and gamma radiation responses which are independent of energy above 100 kev. The maximum departure from energy independence is about 30 per cent and occurs at 50 kev. The outer, ribbed structure is made of nylon and forms a short cylinder about 11/2 in. in diameter and about 3/4 in. high. Filling the space between the ribs is a conducting plastic film approximating the human epidermis in thickness and forming one plate of the chamber. The electrical capacitance is in the air gap between the plates, and in the insulating plastic base between the lower plate and the metal cap which holds the dosimeter to the wearer. Calibrations for beta particles were made with 2 pi geometry obtained by inserting the dosimeter in a paraboloidal cavity formed in a rotating solution of a betaemitting isotope. The response varies from 38 to 63 per cent of the dose to the basal layer of the epidermis for isotopes emitting beta particles with average energies in water from 52 kev for S/sup 35/ to 694 kev for Y/sup 90/, respectively. (auth)
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- DOE Contract Number:
- W-7405-ENG-26
- NSA Number:
- NSA-15-001525
- OSTI ID:
- 4142260
- Report Number(s):
- ORNL-2730
- Resource Relation:
- Other Information: Submitted to Vanderbilt Univ. Orig. Receipt Date: 31-DEC-61
- Country of Publication:
- United States
- Language:
- English
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