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