{PEESay
ec
*
aw sone eee
mea”.
uncertainty of these data was discussed under Criteria Il.
They do suggest,
however, that if the contamination of a relatively large area of the exposed
ar
body produces less than one roentgen infinite gamma dose as Measured by a
survey meter held four inches from the surface there is a large probability
that beta burns will not result.
(See also discussion under Criteria II.)
Doses From Snai) Sources
When the same dose rate reading is produced at a given height above a
surface from a smaller area, the amount of contamination per unit area is
greater (other factors being equal),
Therefore, it would seem desirable to
reduce the recommended dose rate levels when reletively small arcss are ine
volved.
It is recognized that radiation from
enother nearby spot may con-
tribute to the survey meter rescirg when monitoring a smell area on peorsorn-
nel, but this has not heen taken into account. first becsuse of the difficulty of establishing a prior eppraisal of this variable factor and, second,
whatever this contribution may be it will now become an added safety factor.
Of course, the problem is still complex because when considcring
smaller cnd smaller aress the eventual end point is a single particls,
dan
estimate of beta doses at the surface of an imaginary sphere surrounding a
fallout particle is given in appendix E and an estimate of betsx doses from
a single particle required to produce recognizable erythema is presented in
appendix Ff.
Calculations indicate that the specific activity of some indi-
‘vidual particles found in fallout would be great enough to produce recogniz~
¢
able erythema if held in contact with the skin for less than one day, yet the
gamma dose rate reading at 4 inches may be relatively small (See appendix G.).
Additional information on doses from individual particles has recently
beenreported,”around
*HW~33068,
A status report.
Sept. 15, 1954.