HOW TO PMCS AND OPERATE
RADIOLOGICAL DETECTOR
STANDARDS: Be able to perform a PMCS and operate AN/VDR-2
Radiac Set. Prepare Radiac Set in accordance with TM and
stating the contamination reading obtained from an area survey,
personnel monitoring, and equipment monitoring.
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DESCRIPTION:
1. Use to locate and
measure gamma and
beta particles.
2. Lightweight, battery
operated, and self
testing.
3. Measurement is in Gy
(unit of Gray)
4. cGy - centigray, Gy –
Gray, and uGy –
microgray.
5. Negligible risk factor
is 1 cGy.

WARNING!!!!
• The high range detector
contains one (1) nanocurie
of Thorium (th) 232, and is
controlled by U.S. Army
Reg. 385-11.
 RADIACMETER
 PROBE
 POUCH
 STRAP
 1. Detects, measures, and
displays level of
gamma radiation dose rate from .01 uGy/hr to
100 Gy/hr.
 2. Detects and displays level of beta particles
dose-rate from .01 uGy/hr to 5 Gy/hr.
 3. Measures, stores, and displays accumulated
dose (total dose) from .01 uGy to9.99 Gy.
 4. Flashing display to indicate reduced
accuracy condition when measuring dose rate
from 10 Gy/hr.
 1. Liquid
Crystal Display (LCD):
• 3 digits decimal point
• Unit of measurement
• Indicates low batteries or fault
 2. Can
be vehicle mounted
 3. Audible or visual alarm independently
preset for dose rate and accumulated
dose.
 1. Main
power- 3 ea
(9 volt batteries).
 2. Vehicle power- 24
VDC.
 3. Main power battery
life- 100 hrs.
 Will
retain memory
for 5 min. after
batteries are
removed.
3- 9 volt batteries
 1. Low
battery indicator (flashing/hr).
 2. Decimal indicators.
 3. Digits.
 4. Dose units.
 Routine
Checks:
• A. All cables.
• B. Loose or broken lights or covers.
• C. Inspect panel.
• D. Remove all foreign debris.
• E. Inspect batteries and compartment.
 1. The
AN/VDR-2 must be turned off
when disconnecting/charging probes or
batteries.
 2. Install batteries.
 3. Install meter in pouch.
 4. Conduct pre-operational test.
 1. Set
power to ON.
 2. Set ALM to AUD.
 3. Press and hold CLR/TEST button until
alarm sounds for 2 seconds, then release.
 4. When the segment displays, insure it is
exactly as shown.
0.00 uGy
55.5 cGy
11.1 uGy
666 cGy
222 uGy
77.7 Gy
.333 cGy
888 Gy
4.44 cGy
999 Gy
 5. Set
ALM to off, then VIS. The dose rate lights
will come on.
 6. Once the segment test is complete the unit
will automatically go through the unit/digit test
and electrical test.
 7. If all tests are ok, you will see a flashing “9”.
 8. If there is a fault, you will see a flashing “8”.
 9. Once you see the flashing “9”, press the
CLR/TEST button.
 10. Tests are complete.
 1. Surveying
for
beta/gamma
contamination.
• A. Stand in an open
area, 10 meters from
any shielding objects.
• B. Hold unit waist high.
• C. Slowly turn in a full
circle.
• D. Record highest
reading received.
 There
are 2 types of
monitoring
procedures.
• Direct
 Outside of any shielding
objects.
• Indirect
 Stand in middle of room
or area and do testing.
360°
Step 1 (b)
 Simplest
and most precise type of
monitoring.
 Consists
of unshielded dose rate
readings.
 Used
when conditions and Operational
Exposure Guidance (OEG) permit
360°
Step 2 (b)
Center
 Measure
dose rates within an area
shielded from radiation.
 Allows
the unit to measure radiation
levels and still keep exposure to a
minimum.
 Preferred
method when operating in a
contaminated area.
 2. Determining
Background Radiation.
• A. Turn or walk away from the suspected
•
•
•
•
•
contamination.
B. Open beta shield.
C. Observe reading for 5-10 sec. Record highest
reading.
D. Multiply by 2.
E. If the reading is twice background or higher,
contamination is present.
F. Report the results.
 4. Monitoring
personnel.
• A. Take background.
• B. Have the person being monitored stand with
feet apart, and arms extended with palms
upward.
• C. Hold probe 1 inch from personnel.
• D.. Pass over entire body, starting with the head.
• E. Any reading above the background is
contaminated.
Contamination: Before something
can be considered contaminated, a
reading 2 times higher than the
background must be obtained.
 Your
background reading is 2 uGy/hr;
multiply by 2 which gives you 4uGy/hr.
Your open shield reading is 3 uGy/hr and
the closed shield reading is 3 uGy/hr .
Both readings were not twice the
background, therefore. No contamination
is present.
 Beta Only• Your background reading is .2 uGy/hr times 2 is .4
uGy/hr. Your open shield reading is 2.5 uGy/hr
which is more than twice the background reading.
The closed shield reading is .2 uGy/hr. It is not twice
the background, therefore, you have beta only.
 Both Beta & Gamma Contamination• Your background reading is .2 uGy/hr times 2 is .4
uGy/hr. Your open shield reading is 3.4 uGy/hr
which is more than twice the background reading.
The closed shield reading is 2.2 uGy/hr. It is also
twice the background. Therefore, you have both beta
and gamma radiation present.
QUESTIONS??