Navigator 2.0 User Manual & Service Guide
N2-5000-07-001 Rev 7
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38-
Revised 10/16/2018
www.Dilon.com
energy window inside the control unit.
The Verification of Standard Gain uses 122 keV energy photons produced by the Isotope of Cobalt-
57, to create a known signal in the probe. The control unit expects these detected photons to be in
an energy window corresponding to the CENTERED (>0<) position of the test. The control unit also
has a test setting for an energy window BELOW (-) the expected signal, and an energy window for a
signal ABOVE (+) the expected signal. The desired outcome of the test is that the signal is greatest
in the CENTERED (>0<) position, as revealed by the highest count rate seen in the control unit
’s
display. The details of the test are given below.
11B-2. Verification of Standard Gain (Calibration Quick Test) – Procedure. For CABLED
PROBES only.
1. Clean the PROBE and, if used, the CABLE.
2. Charge the BATTERY, and install it into the CONTROL UNIT.
3. Place the system controls as indicated in Table 11B-2,
“System Configuration - Cobalt-57
Alignment
”.
4. Align a 57 Cobalt source directly with the probe tip. Maintain this
exact
position between the
source and the probe tip for the duration of the test.
5. Place the system controls as indicated in Table 11B-2
“System Configuration - Cobalt-57
Alignment.
”
6. Place the SCAN/Calibrate Control in the CENTERED position, which is indicated by the
following symbol on the SCAN/Calibrate Control (>0<). Obtain a ten-second count. Record
this total.
7. Place the SCAN/Calibrate Control in the BELOW position which is indicated by the following
symbol on the SCAN/Calibrate Control ( - ). Press the COUNT control to obtain a ten-second
count. Record this total.
8. Place the SCAN/Calibrate Control in the ABOVE position which is indicated by the following
symbol on the SCAN/Calibrate Control ( + ). Obtain a ten-second count. Record this total.
9. The highest count should be when the SCAN/Calibrate Control is in the CENTERED (>0<)
position. The count in the ABOVE position ( + ) and the count in the BELOW position ( - )
should be less than the count in the CENTERED ( >0< ) position. The observance of these
relationships verifies that the probe and control unit have the same standard gain.
10. Return the SCAN/Calibrate Control to the SCAN position.
11. Return the other system controls to the settings for normal use.
12. End of Test.
Table 11B-2. System Configuration – Cobalt-57 Alignment during Calibration Quick Test
Component/Feature
Setting
Cabled Probe
Cable connected to probe input
CALIBRATE control (rear panel)
(>0<), ( - ), ( + )
ISOTOPE control (rear panel)
Technetium-99m
THRESHOLD control
As desired (no effect)
POWER switch
ON
RANGE control
As desired
VOLUME control
As desired
NOTE:
Because the system is designed to detect slight changes in the location and intensity of
radioisotopes, the test source must be maintained in the same direct alignment and distance
Summary of Contents for Navigator 2.0
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