—
history.
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On the remaining tests, the detectors were installe:
in the Alpha blockhouses and viewed the bomb center through
collimation holes or pipes.
Four Alpha blockhouses were
maintained by EG&G to make possible Alpha coverage for the
various shot areas.
These stations were No. 1310, Yvonne;
No. 1312, Janet; and Nos. 1311 and 1525, Irene.
To obtain at the detectors a signal representative of the
neutron @aignal, it was advisable to limit the emerging gammas
by an aperture near the device,
In addition, collimation at
the detectors was accomplished by means of pipes which extended through the thickness of the blockhouse wall.
Inside
the detector room were adjustable baffle walls containing
collimation holes, which were spaced for alignment with the
detectors.
The system provided for collimation ratios as
high as 50:1.
The physical properties of the detector areas
varied from station to station, but in all cases both the
source aperture and the detector collimators were in alignment with the device at the point or points of interest, and
the detectors had their center lines along the aiming line.
Actual detector alignment was done by transit.
When it was necessary to reduce the gamma signal,
attenuators were used.
These were in the form of lead
shielding placed either in the collimation indentations on
the inner blockhouse walls or in front of the detectors on
their scaffold platforms.
Simulation of shot conditions in the detectors was
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accomplished by means of flash tubes which operated near the
expected alpha value.
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