sion of better than two percent, including drift effects, over a three-week period.
The
completed detector head, including ion chamber and electronics, was encapsulated in
Hysol 6020 casting resin.
A typical calibration curve for these detectors is given in
Figure 2.2.
2.2.2 Residual Instrument System Recorder. The two-channel recorder used with
this system consisted of an Esterline-Angus-chart drive to supply the time base and
10 ®
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te
EF
0%
he
@
°
x
o
de
0?
=
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°
a
-
tas
o (10
:
E
= 7 February
o
3
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A: 2! February
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= 8 Febru ary
107?
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107!
10
102
Frequency, pulse/min
Figure 2.2 Graph showing a typical calibration curve for
the Conrad detectors. These detectors were calibrated
with the 200-curie Co® source and the 250-kv X-ray generatcr.
two electric styluses writing on Teledeltos paper charts. The output from the detector
head was fed through an amplifier directly to Stylus No. 1, which produced a mark for
each detector-output pulse. In addition, the detector output was fed to a scale-of-1li
counter, thence tu Stylus No. 2. Thus, Stylus No. 2 produced one mark for each 11 output pulses from the detectcr. In this manner, a chart speed siow enough for the required
five-day operating period could be used while maintaing resolution of the fastest anticipated pulse-repetition rate. In operation, the record from Stylus No. 1 was used until
21