Operation TEAPOT Nevada Test Site, February - May 1955. Project 38.3. Evaluation of Civil Defense Radiological Defense Instruments. Report to the Test Director.

摘要

Experiments were performed during Operation Teapot: (1) to investigate the beta-gamma exposure-rate ratio from fall-out to establish design criteria for high-range survey instruments, (2) to evaluate commercial radiological defense instruments, and (3) to investigate the feasibility of the use of commercial and amateur roll film and dental X-ray film as indicators of prompt gamma radiation. The results of the beta-gamma exposure-rate ratio measurements indicate that, for an instrument having a beta window of the order of 50 mg/sq cm thickness, the quantity of hazardous radiation not indicated by the instrument will not exceed a factor of 2. An analysis of the absorption data of fission-product radiation indicates the presence of high-energy beta radiation, low-energy gamma radiation, and secondary X-radiation in large quantities immediately postshot. The soft component tends to diminish rapidly, and the high-energy gamma radiation of the longer-lived fission products becomes predominant after approximately 2 days. The evaluation of commercial radiological defense instruments indicated that: (1) satisfactory calibration facilities must be developed, (2) ionization-chamber survey meters must have sealed chambers to avoid change in sensitivity with altitude, (3) an operational check rather than a simple battery check must be provided for all survey meters, and (4) dosimeters intended for monitoring applications must not demonstrate leakage resulting from high initial exposure and must be relatively insensitive to beta contamination.