Figure 4, of approximately nine decades,
soales of three decades each, Figure 5.
This is divided into four
Those scales ares
A.
2005 = 1 mr/br
Be
0.1 - 100 o/h
C.
10 to 10,000 mr/hr (0,01 to 10 rfnr)
De
1,000 to 1,000,000 mr/nr (1 to 1,000 r/hr)
The low level detector covers the range of scales A and B, and the
high level detector covers scales C and D,
The three decade scale
achieves a compromise between reading and telemetering accuracy
with a minimum amount of scale switching.
The upper limit of
scale D (1000 r/hr) is extended beyond the maximum reading of
the instrument (200 r/hr) to allow for the increase in reading
due to the compensation of airoraft intensities to growmd level
readings.
This will be fully discussed in Section 2,1.,4 on alti=
tude compensation,
201.2
Detector Circuit Description (Figure 6)
The detector consists of two plastic phosphors,
One, 3"
diameter by 4" high, is mounted on a 3" photomultiplier tube.
(DuMont type 6363), and measures the low radiation levels.
The
second, 1" in diameter by 1/4" high, is mounted on a 1£" photomultiplier tube (DuMont type 6467) for measuring high radiation
levels,
The phosphor sizes were experimentally determined for
the range of radiation intensities to be covered,
The tenth dy-
node of each photomultiplier tube is connected to the grid of the
amplifier, however, high voltage is applied only to the tube in use.