bit of information on the nerial survey
system 20 that they might be better able
to use it for their own needs,
I'22 do this on a block diagram
basis etarting with the detector which is a
scintillation instrument used largely in
processing phosphorous and photo metron
tubee¢,.
There is one photomultiplier
tube which is a three inch tube and has a
plastic phosphor three inch diemeter by
four inches high and thia tube covers a
range of radiation from anvroxirately
five micro range to the 100 mild range.
The second tube is one quarter
inch tube with a one quarter inch thick
by an inch diameter piactic phosphor which
covers: the range from 10 MR to 200 ER.
The two tubes overlap in ‘each of
theee ranges an one decade,
This was so
that we wouldn't have to do any scale
switching of the informationcoming out from
the top of the first tube’s range.
The plsestic phosphor’...
was chosen
because of the relatively good energy response;