meacurenents at a height of three feet.
Fast field experience has indicated
that the gamma reading from fonisation-type survey meters at ground level
is sbout 50% higher than at three feet.
Therefore if it be assured that
& ground level gamma reading of a survey zoter is equivalent te a surface
dose rate, the ratio ef beta dose rate at 7 mg/em~ to gamma doce rate at
Sree ie about 200 to
1.
Another approach to estinating the ratio of bete dose rate at 7 ng/ex*
to gecma
dose rate at three feat is as follows.
Aseuning a wmiiforn distri-
bution of 1.0 megacurie per square zile of gamma aetivity, the dose rate
reading from an infinite field is about 4.1 roentgena/hour.” Caleulations
given in appendix B indicate that « like concentration of fallout neterial
will produes about 430 reps/hour at 7 ag/os®. This suggeste a beta te
ganna ratio of about 100 te 1 which ie about a factor of two lower than
the first approach.
Added support to this latter method of est inating
beta doses is found in appendix
C.
Such considerations may be fraught with pitfalls.
above
Por exemple, the
discussion inplies a uniforz distribution ef felbutaeberted,
Ovvicusly,
thie is not correct but how far this deviate: from the facts and to what
extent this influences the results 4s
difficult to assess.
indicate that the production of recognisable beta burns
particle requires a high specifie activity.
Calculations
from a single
(See Policy III for discussion.)
It nay/be,however, that the particles of fallout are eloze enough te have
overlapping of radiation fields and thus require signifieantly lover
specific activity of the particles to produce beta burns.
Weapons",
1950
CLASSIFIED
ec
*'rffects of Atomica
This hypothesis
ee
Ql