RESULTS
3.1

Chapter 3

ond

DISCUSSION

GENERAL

Figures 3.1 to 3.6 are plots of gamma rate versus tim: at various
distances from ground zarce
Exocination of tha figures makes apparent the offact of the shockfront passege tetwaen ground zero and the datector station during the
initial-gamca radiietion. Aftar ths passage of tha shock front, the initial€anna rate rosa almost to the sama valuo as it was at the time of datonation.
Table 3.1 gumuarizes the gecmacradiation data for the stations used
during Shots 1, 3, and 4. The extensive instrumntation originally planned
wag not follow:d because of tim unexpected loss of most of tha equipment
stored on Tow during Shot 1. Out of a total of 30 low- and 5 high~
sensitivity instruments, only seven of the Corser and two of the latter
were salvaged for. suceccding shots.
3.1.1

Shot 1.

Figure 3.1 shows initial-gamsa rate versus tina for

Station250.11onCharlie. Tha increase in rate from 0.35 to 0.9 second
was apparently caused by the cxpanding fireball and the appreach of the
shock front tovard the detector station. The shock front arrived at the
datoctox station at 0.9 sacond. Tha averages velocity of tka shock front
batween ground zaro and tre detector station was computed to ta about

8,000 fi/esc.

No further data wre obtained because the station was do

Atroyed by missiles at that tims.
The special detector systam at Station 220.11 on Charlia was designed
to datermino the rate or cunilative exmosure dependence of the crystal
Cotacting eloments, as well as to measure the initial-gonsa rate. Rocortsa
Obtelizsd shored that the two detector heads did not track. Loiwvar, it
wag datermired that this vas rot cus to a rata cr doageva depenurnees ef the
erystals, but rather to ecattered yacma radiation entering throuzh the
Licht pipa crd striking tha photomultinlior tube in the station vithout a
gnisld around the ditector bocd. Since a dencity-four nuutrel Plier was
Placad Yatizen the erystels end tho photozultiplier tube to increana ths
ranga to 10° r/pr, tie offect of thy coattered redietion anticin? through

tra Light pire ves to cultiniy ths dimct effect of gama rediction on bls
photemutipliar by cavers) anters of rrunitudae Bacauca of this, Vi
record tont off ccele ds-sddately end save no trus irdteatior of tha caus
rata. Zor station with tha chiele:d dstaetor head rroviticod a good rosenl,
bkeceuge tha lead chfoldins uffeetively attenuated the gacua vedinilon that
Teacind tis phototub by a factor of 100,
Fisure 3.2 plots ranildesd-gitla vata varsus tinn for Stations 209.12
and 220.63. Tho sroph shows thet at Station 220.22, fallont started to
byulld up 19 sinutes after the dstornstion and reacted a cexteea vats of 10°
rf/hr. The integrated exposure for thm first 24 hours was 3,735 re Tha

19

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