Personnel Monitoring (2)

Question 1

List all Personal Dosimetry devices

Answer 1

• DRD or ED
• Alarming Dosimeter
• Film badges, TLD, OSL

Question 2

TLD

Answer 2

Thermoluminescent Dosimeter (TLD)

Measure accumulated dose to body and skin. Contains two lithium fluoride chips of metal foil (one for skin, one for body), Ionizing radiation interacts and frees electrons forming negative ions, get trapped in chip , chips are heated releasing light measured by a photomultiplier tube.

Question 3

OSL

Answer 3

Optically Stimulated Luminescence (OSL)

Thin layer aluminium oxide and filters. Radiation interacts with layers it induces stable effects, when illuminated light = accumulated dose.

Question 4

Film Badges

Answer 4

Double coated film pack (one side thick grained silver bromide or chloride) ,large grains = more radio-sensitive to low levels and expose faster. density of film is compared to radiation energy.

Question 5

List categories for dosimeters

Answer 5

• Passive (no reading capabilities)
• Semi-Passive (battery for reader stations)
• Active (immediate reading)

Question 6

DRD

Answer 6

Direct Reading Dosimeter (DRD)

Ionization chamber the size of a pen, senses and displays exposure dose.
(x-ray, gamma)

Ranges:
Low = 0-220mR, 0-500mR

Mid = 0-1000mR, 2R, 0-5R, 0-20R

High = 0-100R, 0-200R, 0-600R

Question 7

How do DRD’s work?

Answer 7

Conductive quartz fibre attached to an electrode, electrostatic charge is given to both, they repel each other. unless ion pairs are created and move the quartz fibre.

Question 8

PAD

Answer 8

Personal Alarming Dosimeter (PAD)

alarms an audible warning when it hits monitors a preset dose rate.

calibrated yearly

alarm for exceeding 5mSv/h or total dose exceeds 2mSv

Question 9

ED

Answer 9

Electric Reading Dosimeters (ED)

Alarming feature, measures accumulated dose and dose rate with a direct reading display