A Direct Reading Rate Meter for High Intensity Penetrating Radiation
- Naval Medical Research Inst., Bethesda, MD (United States)
- Naval Ordnance Lab., White Oak, MD (United States)
Inherent technical difficulties in the measurement of X-ray intensities from 100 to 5,000 r/minute, at exciting potentials between 400 and 2,000 K.V.P., have been investigated. Extending the ranges of conventional condenser-electrometer dose meters by use of absorbing media not only increases energy dependence, but is also found to cause an apparent displacement in effective geometrical location of the ionization chamber. 250 r, 1,000 r and 2,500 r condenser chambers have proved susceptible to serious errors from dielectric leakage, which increase rapidly with chamber range above 100 r and with radiation energy above 200 K.V.P. Associated measurements of voltage saturation indicate that no error from this source need be expected for full scale exposure times exceeding two seconds. A direct reading circuit has been developed to combine the known wavelength characteristics of “air wall” thimble type chambers with the linear current response of a portable d’Arsonval galvanometer. A 25 r Victoreen chamber, remotely read through lengths up to 70 feet of polyethylene coaxial cable, shows linear calibration from 35 to 5,500 r/minute with over-all reproducibility to the order of ± 1.5 per cent. Ionization readings correspond, within the accuracy of chamber volume determination, to the definitive value of e.s.u./cc. second.
- Research Organization:
- Naval Medical Research Inst., Bethesda, MD (United States); Naval Ordnance Lab., White Oak, MD (United States)
- Sponsoring Organization:
- US Department of the Navy, Office of Naval Medical Research
- NSA Number:
- NSA-07-002058
- OSTI ID:
- 4390984
- Report Number(s):
- NM--006-012.04.57
- Country of Publication:
- United States
- Language:
- English
Similar Records
A RADIOMETER
Use of a Victoreen 500 electrometer to determine ionization chamber collection efficiencies