Sem
radiction is designed to cover a range frocix/hr with e time resolution
of 5 minutes, to 10” s/nr with a time resolution of 0,05 minutes. The
basic circuit is show in Figure 2.1, where the sensing element is en
unsaturated fon chamber.
The fon chambor was designed to have a current
output proportional to the square root of the ganma<-exposure rete.
The
overall detector response ds given by:
f= we/2
vhere:
(2,2)
£ = the output frequency
rr th< gawaorexncsure rate in rir
k = & parameter chosen to meet apecific design cojectives
In laboratory calibrations on a 250-kv Xray beam, these detectors.
have shown a procision of better than 2 percent, including drift effects,
over a threeeveel period,
The comleted detector head, including fon
Goi Onl Ciccervniles, was Ancapsulubcl in Lys.i 65... casting resin.
i ty, tect eclibroticn curve for these detectors is give. in Figure -.".
2aca2_TheInstrumentRecorder. The two-channel
recorder used with this system consisted of an Esterline-Angus chart
drive tc supply the time base ardi tro electric styluses writing on
Teledcltos paper charts.
The output from the detector head was fed
through an amlifier directly to Stylus Number 1, which produced a mark
for each detector output pulse. In addition, the detector output was
fed tc < stale-cf-11 counter, thence tc Stylus tamber 2.
Thus, Stylus <
rroductl eno mort for eoe: Ti eutewt pulse: frown. tin detector.
In this
manner, 2 Chart-speed glow enoug. for the required Sday operating
period could be used while maintaining resolutionof‘the fastest