vaices
-now Cat wariatsen wita angle, at
least Wleecna Wane ~5 Sccress,
is
about as calculated.
Orange dota substantiate transport caleulaticns threwck the atar-prere te
about the estimaced accuracy of the calcslaticas.
INSTRMENTAT [ON
ho
3
3.2.1
Design Criteria
Instrmmentation design was inilvenced by space and weigher Linitaticas ta-
pesed by che inserumene carrier.
In selecting systems and cooponents, prefer-
ence was given to those which were sizple and compact.
Timge-of-flight cechniques wera considered for seasuring the neutron energy
Spectrea at the teo highest Teak stations, 209 and 252 (Fig. 1.1); hnever,
such a systez would have required a record-pla,back meowry @evice because of
boch early-cime radiofrequency blackout and frectency-resowunse lisitarions of
the telemetry system.
This would have resulced in a very complex system for
developwent within the linzitations imposed by the instmmest carrier ani cine
At the lower Teak stations, 29 through G0, neutron transport woula
scales.
bave complicated tise dependence of che flux energies to an extent that spectral determination from a time-of-flignt aeasureseot would have been practicall,
impossible.
Fur these ceasons it was decided that a modified fora of rhe con-
ventional threshold-dectector technique should be used.
This systea in principle has two aajor advantages over a time-of-flight
system, nacely:
(a) activation samples thenselves act as a mecwry device in
thac their activity decreases slowly wita tise so that counting ary continue
during the entire cine of the rocket's descent, and (b) activation sazple aeasurements give ao energy spectrum independent of the time depesdence of neutron
flux.
Disadvantages of activation techaiqces will be apparent in che following
sections.
3.2.2
Instrmment Description and Calibration
Conventional threshold activation samples, i.e., zirconica, sulfur,
uranita 226, neptunius 237, and plutoniim 235, were used,
3eta cather than
gamma activicy of the sulfur and fission foil sacples was counted, sizce it
&
was expected chat gazea background from che detonation would interfere wita