Fluke Biomedical 05-582 - Manual (Page 7)

Operation
Operation
2
2-1
Section 2
Operation
2.1 Operation
Holding the instrument in front of you, press the red button on the right side of the unit and HOLD IT IN.
The digital indicator will come on, and counting will commence automatically. When the green READ
indicator light on the right side of the panel lights up, in approximately four to five seconds, the
measurement is complete. The display will be in mR/h (milliroentgens per hour). This display will remain
illuminated until the button is released.
During the counting period of approximately four seconds, a small LED indicator below RATE will blink on
or off for each detector pulse, indicating that the instrument is operating properly. The RATE indicator
can be used to determine the area of highest activity before the actual measurement is made, if desired.
Immediately to the right of the RATE indicator is a LOW BATTERY indicator. If the low battery indicator
flashes on and off during a measurement, the batteries should be replaced.
If the display blanks completely at the end of a counting cycle and the low battery indicator is not flashing,
it is an indication that the field is greater than 99 mR/h. In very high fields, the display will never come on,
but in fields up to about 500 mR/h, the display will come on briefly before it is completely extinguished.
The PRIMA 7 is designed to round off the digits on the display. In the round off procedure, the display will
read 1 for fields above 0.5 mR/h and will read 2 for fields between 1.5 and 2.5 mR/h, etc.
2.2 Operation Check
To check overall consistency in operation of the PRIMA 7, a license free radioactive check source such
as catalog number 62-103 containing approximately ten microcuries of
137 Cs should be used. To check
for proper operation with this source, place the source (label side down) directly over the target area
indicated on the top of the front panel. Because the check source is not a calibrated source, the reading
should be, on most instruments, between 10 and 15 mR/h. The main use of the check source is to verify
that instrument operation is consistent from day to day. Typical readings from day to day will be from 11
to 13 mR/h with most readings at 12 mR/h.