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Extended- and Point-source Radiometric Program

出版	Health Physics Division, Oak Ridge National Laboratory, 1962
URL	http://books.google.com.hk/books?id=f9tYAAAAYAAJ&hl=&source=gbs_api
EBook	FULL_PUBLIC_DOMAIN

註釋An extended-source calibration area was set up in the Nevada Test Site area to encourage a standardization of airborne radiometric instrumentation among several government agencies. and private companies. A simulated plane-source array was laid out with positions at 100-ft intervals in the form of a square 2000 ft on a side. For ground measurements a smaller square array of 100 positions at 10-ft intervals was placed in the center of the large array. Two sets of sources were used in the array. Cobalt-60 and cesium-137 sources of 4.5 and 15 mc, respectively, were available for the large array and sources one hundredth of these values in the smaller array. Point sources of Co(exp 60), Cs(exp 137), and I(exp 131) of the order of 2 curies each were available for comparison with the area sources. Measurements 3 ft above the area sources indicated 200 micronr/hr for Co(exp 60) and 225 micronr/hr for Cs(exp 137). Four government agencies and one private company participated in an intercalibration exercise during November 1960. Various types and sizes of aircraft from a Cessna 172 to a Douglas Dc-3 were used. Various instrumentation devices, mostly scintillation type detectors, were tested. Flights ranging from 100- to 1000-ft altitude included background measurements, instrument calibration, intercalibration, proof-testing equipment, comparison of point- and area-source measurements, measurements of air attenuation and buildup of gamma radiation, and gamma-ray spectral measurements.