a. Place tester on prepared site so that the source
b. This count variation is a function of the random
tube hole is positioned reasonably close to the hole in the
surface to be tested.
c. This will obviously produce a predictable error in
b. Standing slightly behind the tester with your feet
the final result of PCF values.
placed comfortably apart, flex your knees and bend your
body slightly forward above the waist.
d. The error, identified as "Precision" can be
charted as follows: (1 minute counts)
c. Brace your right elbow on your right knee,
grasping the cast lip of the tester with the fingers of your
d. Put your left hand on the source tube handle.
e. Allowing the left edge of the tester to remain in
contact with the surface, lift the right edge of the tester
two to four inches above the surface.
This error is the tester's repeatability. The final accuracy
obtained on the site is also a function of how accurately
f. Release the spring lock on the source tube
the factory calibrated the tester and how carefully the
handle with your left thumb and push the source tube
operator chose and prepared his site.
down approximately 2 inches.
The value of the final result is also a function of how
g. Peeking over the front edge until you just see the
representative of the overall project the selected site is.
end of the source tube, lower the right side of the tester
and guide the source tube into the hole in the prepared
Precision is also influenced by the selection of time
period on the Operations Touchkeys:
h. Lower the source tube to the desired depth.
1-20. TAKE A NUCLEAR READING ON SITE
Once the site is prepared, a standard count is available,
and the tester seated, a field count can be obtained.
No advantage is gained from repeating a count on
Select the time touchkey which will produce the desired
exactly the same site. It is permissible to rotate the
precision versus time available for the test
tester 900 or more on a site to obtain two views of the
location, but there is nothing to be gained from taking
1-21. FIELD COUNTS AND TRANSMISSION
more than one count without at least moving the tester.
It would be better to move the tester to another site
a. Site is prepared, standard count recorded
nearby for the second count in order to obtain a better
representative sample of the overall project.
b. Seat tester firmly.
c. Release source handle trigger and lower source
factors to the tester readings, we will observe that:
to BS or AC position as desired.
a. The tester will not count exactly the same two
d. Press desired Operations Touchkey.
times in a row except by coincidence.