OBJECTIVES
The operations with which this report is concerned were carried out as part of Project
2.66. The objevitves were to: (1) determine whether any corr<iation exista between the
contact radtation hazard on aircraft that have recenuy fowu through nuclear cloucs and
the dose rate measured on the surface by an AN/PDR-39 (T1B) survey meter; (2) study
the distribution, intensity, and docay of the conta'nination that causes the contact hazard;
and (3) evaluate the amouni of protection offered oy each of a number of different types
of gloves.
1.2.
BACKGROUND AND THEORY
During recent years concern has grown over th: potentially serious contact radiation
he cd that might be encountered by personnel who come in contact with aircraft recently
contaminated by flight through nuclear clouds.
This concern has been prompted in large
part by theoretical conside. ‘ations ag typified by analyses such as those in References 1
and 2.
For the purposeof their theoretical analyst: of the problem of beta intenaities, the
authors of Reference 1 assumed an idealized geometry !n which the contamination was
considered to be distributed uniformly over an infinite plane.
Based on this asaumption,
the ratio of the beta intensity to that o. the gamma was calculated to be about 130 to 1.
It was concluded that the beta hazard was of sufficient magaitude to warrant special instrumentadon for measurement of the hazard in all areas cf fission fragmont contamination.
Similarly, it was shown in Refercace 2 that in air or tissue the fon track censity of
moderately energetic beta particles Is about 76 times that of tne photon of compareble
energy; hence, if two betas are emitted for each photon, the ratio of these fontration
intensities would be 150 to 1.
As a result of analyses of this kind, experiments were undertaken to measure the
relative tonization intensities of beta and gamma radiation under conditions that might
be encountered in the field.
Reference 3 is an example of such a field experiment. In
this particular instance, the measurementof the Leta- gamma ratio was undertaken in
desert fallout regions. While this was an expe.iment of primary interest to ground
troops, some of the resulta can be applied tc the aircraft problem. Of particular interest
ia the finding that a somewhat-high ratio of veta to gamma fonization intensides could,
in some tnstances, be changed to a field of almost pure gamma by removal uf one relatively large particle in the vicinity of the area of measurement. Such a particle may
contribute most of the beta radiation for that par.icular insasurcuent. This demonstraiss
the fact that the effects of beta radiation will be experienced only in close proximity to
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1.1
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INTRODUCTION
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