TM 5-6635-386-12&P
WARNING
Insure that the tester handle is placed in the safe
position prior to placing the tester into the
approved carrying case.
Upon completion of testing, remove battery pack and
store in storage case separately from tester. There is no
ON/OFF switch and today’s last readings will still be
available when the tester is used next.
1-5. SOURCE ACTUATION
The shutter is released by pulling back on the handle
latch pin and pressing down on the handle.
The shutter is spring loaded and closes automatically
when the handle is raised to the SAFE position.
The operator should insure proper latch or handle
position by visually checking the latch pin for full forward
location at the desired depth.
Lock the source rod when in storage by pushing in the
lock button on the end of the rod. Key required to unlock
handle.
After repeated tests the shutter mechanism will become
dirty with accumulated soil pulled into the chamber on
the end of the source rod. The shutter will jam or
become sticky. See Para 3-6 for shutter maintenance.
Do not force the source rod to open the shutter.
1-6.TO MEASURE OR TAKE A TEST, GENERAL
The following operations are required to take a field test:
a.
Take a Standard Count.
b.
Prepare the Site.
c.
Take a Reading on the Site.
d.
Determine Moisture and Density from the
Charts.
e.
Compute Percent Compaction.
WARNING
Insure that the tester handle is placed In the
safe position prior to placing the tester into the
approved carrying case f. Store the Tester
Away.
1-7. STANDARD COUNT
Nuclear tester performance is affected by the decay of
the radioactive source, by aging of the electronic
components, and by minor mechanical wear and tear.
As with any measurement tool, it is necessary to check
the tester against a reference standard periodically to
insure continued accurate operation.
This is achieved with your tester by the taking of a
Standard Count on the reference standard furnished with
the tester. Variations in tester performance will affect the
Standard Count in the same proportion as they will affect
the field counts.
Should variations in tester performance occur, these
variations will affect both the field and standard counts
proportionately, thus the final ratio remains constant and
the tester remains accurate. The standard count thus
becomes a means of continual calibration correction for
the nuclear tester.
A further benefit can be achieved from the standard
count due to the statistically reliable nature of the decay
of the radioactive source over short periods of counting.
The
following
paragraphs
describe
methods
of
evaluating tester performance using inspection of a
series of successive counts in a standard count series.
1-8. HOW TO TAKE A STANDARD COUNT
Manual and automatic are two methods of taking a
standard count. Both use the same mechanical setup.
They differ only in the method of accumulating the final
count results.
1-8
