2.2.5
Program 13, Alpha Measurements
a.
Objectives
To measure alpha as a function of time for the fission devices or
primaries in order to determine whether they worked properly and in case
they did not, to aid in diagnosing the trouble.
b.
Techniques
1. Alpha detectors, each consisting of a plastic fluor and photocell or photomultiplier combination in a light-tight can, were mounted at
appropriate distances from the device to give a wide range in sensitivity.
The signals were conducted over coaxial cables shielded against gamma,
neutron, and electromagnetic radiation to concrete bunkers. These signals
then were displayed on a series of high speed oscilloscopes together with
timing frequencies and were recorded by cameras.
2. Data were obtained by measurements made on the film traces
and analyzed to give the time history of alpha of the device.
c.
Results
The results of the alpha measurements are given in Table 2.4.
The
alpha record is particularly useful in understanding the behavior of boosted
devices.
2.2.6
Program 15, Photo-Physics
2.2.6.1
Diagnostic Photography
a.
Objectives
1.
2.
3.
b.
To determine yield by fireball photography.
To determine yield by Bhangmeter records.
To determine symmetry of fireball growth by photography.
Techniques
1. Framing cameras were operated from three or more photo
towers on each shot to record the fireball history.
.
2. Measurements of fireball radius as a function of time were
made from the films. Empirical scaling was used to obtain an estimate of
the yield.
3. The time history of the light intensity was obtained for each
device by a photocell-oscilloscope-camera combination to give the time to the
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aah;
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