GR-100 User's Manual Revision 1.2
2.0 Operation
In this case the unit indicates that a GAMMA alarm has occurred. The displayed dose rate is the
maximum value measured during the period the alarm message is on the screen. In the alarm
condition, the displayed value is obtained from 1 second measurements. The short integration time is
used to learn about the dose rate maximum to make searching (in Search Mode) the radiation “hot spot”
easy. The real dose rate, the measure of the health hazard, is stored in the memory as dose history.
Press SHORT to go to the SEARCH MODE. After
pressing SHORT, the following screen is displayed:
As noted above, in the SEARCH mode the count
rate, dose rate and audio tone are used to
accurately locate the source of radiation. The
higher value or the higher frequency of beeping
means that the detector is closer to the source.
A SHORT press of the button at any time in the
SEARCH mode will return the unit to the MONITOR
mode. If no action is taken in SEARCH mode for
15 minutes, the unit will return to the monitoring mode automatically.
2.8.3 Search Response
The following response is obtained in the SEARCH mode:
•
As the unit approaches radioactive material the COUNT display (234 above) increases to show
that the radiation intensity is increasing.
•
If any neutron radiation is present, the neutron data will be displayed in counts/second.
•
As the radiation intensity increases, the AUDIO frequency will increase proportionally (if enabled),
thus making it easy to locate the source in an “eyes-free” manner.
•
The audio signal responds to radiation from just above the alarm threshold level to very high
level (the count rate of 2000 cps) in progression of beep frequency. The frequency of beeps is
proportional to the count rate in non-linear manner. Using this method, the response to low
radiation levels is enhanced to enable the search for distant or shielded sources. The beep
frequency remains constant above 2000 counts per second.
SAIC/Exploranium – Proprietary
Page 9
Revision Date:
November 2004
Summary of Contents for GR-100
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