Tereral Taeceipt
ion.
Pann
Arr‘.
Reasitements were “ate oyer
sicreys wer 8
planes oaqcdp ed woth SOU TAS ESe, gearitive, wife ranve gare
selatiliation Snstrivertes capable of ~eae ries getuot |
ofan lit
saa “OH omrtse from aliitades
Siryey Slight
res
Of FON, or ereater,
7 were wate cover creedeteocmiran pattern) tanta adits
achiave axiom
coverage im salacted acreage
tre Marshall, Gar ine, “arinnay ard Yawaidar
triramithadd te the wick
tears Inccudes
ands.
Tata sac
Soree reorsiorally from ervey abreraft
Ete byt more penera® Ly from the wpiadror hase at the cracls
in
af each Miipht.
“paritione
The scintareters were onerated in Slight oy alrerafe
crey
rembers triined in the¢dr uae. Usually two instrumerts were
carried, one reserved as a arare. “he secintameter crerater reno rlad
beckrprrund reating, pomition, alvitute amd radiation tatmenrity fo
each island in the survey cat ern.
Jarksrouad san measured during
the adpreach to each istard at a distance of several niles. “hese
data were traramitted ti Trask Force “ewlquarters were ‘le intensity
at the atated altitude aver each istand was comynrtes to ground in-
tera'ty bv Treant of a calloration curve.
.
Measurenents were zenarally made from an altitude of -'. feat. Were
the upper range cf the instrument (160 mrf/ne’ wag exceelad at ore fhes
the neasurement would be rescated at signer altitudes until a vaiue
within the range 7f the {natminent wast cbtainal. Altitude wag reasured with a radio altimeter. The ratic of ground intensity ‘o the
intensity at tne operators position within the aimratt at 77°C tM. ig
appreximately 1. (Scintameter calibration is described in Section VI}.
The low and of the scintameter range 1s 0.002 me/or sot at theoretically
the minimal detectable armind intensity fs O.017 arftr.
In
reality, the minimal detectable value is controlled primarily ov the
gama backgrvind.
This backrround can be caused by cosmic rays,
nay cational instruments, fe reraft contamination, and possibly resi~
Seal bor> debris an tee wire “he oractical lower limit during CASTLE
was in the order of C28 mr/ir.
Following SPAT", sur sey narties, out ashore ab se~oral atolls in tre
area of fea yiest fallout, recomied large radiation intensity eradients
in darsct ons accreximately normal to the fallout patr. At Rongelap,
aoproxirately ainety miles from ground zero, a difference of an order
of magnitude in pamna radiation was noted Latween two opvagite ends
of the atori, a distarce of about “C miles. Tris evidence was substantiated hy #SLE CLizhts repeated on B 4 3 and 3 ¢ 19 during whirh
Cc
‘Iustre: ats are described in Secti
on Vi.
anfelt illferences betyees
Ronpeals ard foumfola dis‘.
These large gradfents were
meter operators tad not
Sstards Lo rveved within
@ stantardize subgaqient acrin
?
MtOll waa selected foe reicere-
with FOMEC are in referensa ts
2
a
8
2
Pe
“ear red
acetis,
SEANT
meas
Aayt
~
at stray
at
ee int ge
i each
on mer ints begter ey
The plarned method -¢ valootir.
fis based sp penopte cram
monitcring statiors was tracp
lic
4to
after TAY Ine
the eyacuttion -¢
: Roncer a, the
enly
ereverl
“fe
a
nay yreund statio
’
n tn ¢
v
orbit, Wu. abner lew) Winds
rererally fren ts wes
.
a soth
t Lo
nethw
es ,
uest
vatterr ARTE
A
nraved to he the restouseN:l
anid ~ at ome -f 4°) cat—
terns. [t was disnatchad routin
ely
on
yoon 38 1 .
efore this was dore
4
air
particle tratectery forecast, S
%
were reviewed for the pnosai
btt ity
of the cloud being over the
northers Varshails on 2 & 1,
The fopns
Caz’ s were reasonatsty relia
ble fora
tr b thoes ta
hourse Usually, & forecasts stace
d ¢
heyonn the YUperet ais
by (ff # 2h hours. Sirveys on D
i AY were avoided because of the v
isk
of contaminating survey aircr
aft
The very least resutt, of flyin
g
thra the cloud detels youle
-robal ly have be en the elimi
nation -F tre
afreraft from furtser low inten
sit: measy fements. Fallout was
,enerally not forecast to he coor
rete, ia the norttern Marshall's
until
late on D day or early oD & le