Mtg oe tt ey Bae
activity than ground yawa measurement, particularly where fallout
It was also found to give earlier indication
of arrival, this probably hecause of its greater sensitivity,
There
We
MEMTATICN
INSTRU
!
Le Aerial SurreyMonitoring
la reason to believe that these characteristics would apply in Pacific
teste and aight prove useful in warning of fallout arrival.
Ae
The SCLSTAMETER,
Ganeral Descriptione®
Taw SCINTAYETIR, a self-
contained, cater root, battery oporated scintailation type eran
A particularly gratifying ach levement of this pro,;ram was the utilisation of personnel, untrained in radiation instrumentation, for the
Operation of the automatic monitoring equipment. This represents a
tremendous economy in the use of the scarce musber of personnel
trained in radiation safety techniquese It has been demomtrated
that a fairly cosprehenaive acnitoring program can be cont imed cover
a protacted period without tying up a large number of trained personnel.
detectcs with a fost ceaponse ting, was caed faq all aerial surveys.
The unit weitere oo icntly less thas Sive mounts with
battertas.
The
single seer scule ia divided lomritheically enabling severnl de-
Cades of retintion intensity to be read without switehing arraneemerta. Tw modela, the “‘H-3-3 and M50, have a range from 0.003
te 100 arfor and titfer only in battery comlement. A third model,
the Hel-A, has a rarge from 0.001 to 10 rfpre This high Level
inetrumert wes develored for tre use of cloud tracking aircraft
B.
Conversion of Aertel “eagur
te to Ground Level (ntenaitiess
An air to grouni calibeation preaadure wa* tar
r the
STi.
VETER at Priwesck in Cobraary prior to CASTLE and repeated at Bikini
a fone dase sftare BPAY. Similar calibration war had been conducted
ered awe
and was soe rtangivaly on the WILSON Mltehted it wae not utilized in ato’! svreert but wae serviaad by “ASL personnel.
for the SCin7tire,| syedaneesos ta the SCINTAMETER, prior to its
netelSeattnc Jo ga) A
use tiring 'VY.
The ealibration pme-dure consisted firet of enadueting « ‘horough
survey of the radiation intensity at 3 f%. over an area contaninated
by f1asion products fol lowed by -easuremente using identical instruments cver the sone area from an aireraft at altitudes of from -
50 to 1000 %.
«Ne ratios of the average ground intensity to values:
Reascred at selected a.c’ tudes constitute an atberuation curve
which may be used fy udjueting serial readings Lukan cver areas of
unknown contamination to growuad Level intensitivs.
There are several poesible errors snd variabiees which. nay couse
variations in the sitematiun factors derived... Thecearat rad latier
instrument orrer, (this includes energy dependenséSfiich le dis-
cussed in Section V7, altinater ervor, huma errir;. irrezaiar dis-
tribution of fission products om the ground, fSisetin product age,.
and variaticn in ‘:« abecrption of different sectleas within an air
eraft and betwee~ sircraft. (Soth P2¥ aircraft ast helicopters vere
utilised’), Variation {a ie area of the radioactine source nay also
he suggested ss 1 cause of variation in attermat ion: Ssctor, however,
although the ‘zlanta ured for celibration sites varied sarkedly in
sise and shape, ‘he attenmation factoce vere not masanrabdl~+ 1!/ferant.
“for detailed daseription of ingtruments see "HASE-154, OPERATING CROCTOURZS,
FALLOUT MONITRING POH CASTEE
~58-
new sr bheds se eS dediAShomeseas AE te Leneagtie 7
was of low intensity.