Transcript Electronic Dosimeter

Electronic Dosimeter
Canberra Mini-Radiac
ED Advantages
• Advantages
– Alarms alert user
– Can be read by user at scene
– Can be set to alarm on dose or dose rate
– Can measure both dose and dose rate
– Gamma and x-ray doses
(some available for beta and neutron)
– Able to measure a wide range of doses
ED Disadvantages
• Disadvantages
– Not as accurate as TLDs
– Most have to be programmed
– More expensive than TLDs or DRDs
– Require batteries
– Some are not rugged (but some are)
High Dose Rates
For emergency life rescue
operations, without a high
rate survey meter, you can
use an electronic dosimeter
as a substitute if the
dosimeter can read high
rates (200 R/hr or higher)
Do not hold your dosimeter up to sources
because that can make your dose reading
higher than what your body actually received
Canberra Mini-Radiac Dosimeter
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Max Rate: 500 R/hr
Max Dose: 999 R
Rugged & Water Resistant
Large Display & Large Buttons
Designed to be operated while
wearing gloves and PPE
• Two Levels each for Dose & Rate Alarms
– Low: Caution, Near Radioactive Material
– High: Danger, Snatch & Grab Rescue
Canberra Mini-Radiac
Units
Rate
Button
Dose Button
On/Off
Button
Mini-Radiac: AAA Batteries
4 Types of Mini-Radiac
Alarms
Low Dose Rate = 1 mR/hr
Near something radioactive
CAUTION
GREEN
High Dose Rate = 100 R/hr
DANGER Turn Back
Snatch & Grab Rescue
RED
4 Types of Mini-Radiac
Alarms (continued)
Low Dose = 1 R
Approaching EPA 5-Rem
Limit for Emergency Activities
GREEN
High Dose = 20 R
Approaching EPA 25-Rem
Limit for Life-Saving
RED
Low Dose Rate Alarm
Alarm
Indicators
Visible Dose
Rate Alarm
(Green)
High Dose Rate Alarm
Visible Dose
Rate Alarm
(Red)
Low Dose Alarm
Visible Dose
Alarm
(Green)
High Dose Alarm
DOSE
Visible Dose
Alarm (Red)
Signals
Display
(LCD)
Vibrate
Audio
Signal
Clearing Low Alarms
Clear
Low Alarm
Doesn’t Stop:
Display
Stops:
X Audio
X Vibrate
Press
Clear/Test
Button
Display
(LCD)
Clearing High Alarms
Clear
High Alarm
Doesn’t Stop:
Display
Audio
Stops:
X Vibrate
Press
Clear/Test
Button
Display
(LCD)
Audio
Signal
Light Button
Light Button
Normal Background on Dosimeter
• 5 – 30 µR/hr for Dose Rate
• 5 – 30 µR of Dose for every hour
since dosimeter was cleared
• About 0.25 – 0.5 mR (250 – 500 µR)
of Dose per day if dosimeter is left
on
Training Value Correlation
Low Dose
Alarm
Real World
Values
1R
Actions
Serious
radiological event
•Administrative
controls
•Rotate teams to
stay under 5 R
High Dose
Alarm
20 R
Limit for life
saving activities
•Leave immediately
•Another team
takes over
•OR
volunteer/aware
risks/ w/permission
Low Dose Rate
Alarm
1 mR/hr
Three times
background
•Proceed with
caution
•Continue to
measure dose rate
High Dose
Rate Alarm
100 R/hr
Time to get out
•Rapid Egress
Wearing Dosimeters
• If available, every responder at
radiological/nuclear incident should be
issued a dosimeter
• Wear dosimeter between
the neck and waist
TLD and Another Dosimeter
Direct Reading
Dosimeter
TLD
Dosimeter