26
detonetion.
Little,
if any,
and the actual
correlation exists between the vrobe values
levels of radioactivity present in sea water 4s
determined from samples taken curing the Marsh expedition (Fig. 7)
The lack of sensitivity might possibly have been due to faulty
"a" and "B" batteries in the probe assembly although this is not
likely.
The instrument was sensitive to a J source inserted into
the calibration port several times throughout the duration of the
trip.
Although the instrument,
in its present form,
cannot be used
for detecting low levels of conteéminstion the following modifications might be méde to increase its sensitivity and usefulness.
1.
Incorporate suitable voltege stabitlizgrtion circuits in
the filement, B+, end high voltage supplies (the shipline supply fluctuetes from 80 v to 135 v).
©.
Replace the present crystal and photomultiplier with a
7-inch diameter unit.
3.
Rebuild the water tank to minimize vibration effects on
the scintillation probe and increase the volume of water sround the probe.
.
Incorporate intermediate ranges into the control box
with the following ranges: 5, 30, 50, 300, 500 and 3000
microroentgens.
DOE ARCHIVES
Pish
Levels of redioactivity
uk,
in fish tissues are given in Table
They are remarkably uniform in the three ekipjaok taken nesér
station 23; the liver has the highest level of activity, 186 d/m/g
ae