Knowledge for everyone

1. E
TLD
(THERMOLUMINESENCE
DEVICE)
 What is TLD??
 How does it works
 Radiation detection device
 Exposure type
 Types of TLD -
PRIYANSHI

2. TLD
(THERMOLUMINESENCE DEVICE)
I. THE PRIMARY FORM OF PERSONAL RADIATION MONITORING
DOSIMETER
II. THERMO LUMINESENCE IS THE EMISSION OF LIGHT BY HEAT.
III. TLD MEASURES IONISING RADIATION EXPOSURE BY
MEASURING THE AMOUNT OF VISIBLE LIGHT EMITTED FROM A
CRSTAL IN THE DETECTOR WHEN THE CRYSTAL IS HEATED.

3. 1 ALPHA AND BETA PARTICLES DO NOT TRAVEL VERY FAR.
2. GAMMA AND X-RAYS TRAVEL FURTHER THAN ALPHA AND BETA RAYS.
3. RADIATION THAT HAS ENOUGH ENERGY TO BREAK CHEMICAL BONDS IS
REFERRED TO AS IONISING RADIATION.
4. IONISING RADIATION IS POTENTIALLY DAMAGING THE CELLS/TISSUES.

4. RADIATION DETECTION DEVICE
 Instruments that can identify the presence of radiation.
• in the environment
• on the surface of people (external contamination)
• inside people (internal contamination)
• received by people as exposure
 There are many types of radiation detection devices.
• No single devices can detect all types of radiation.
• No one device is useful in all situations.

5. EXPOSURE
Types of exposure-
 Whole body exposure-person receive penetrating radiation no
portion of the body is shielded.
 Partial body exposure-shielding of sufficient thickness blocks a
significant portion of the person from receiving penetrating radiation.
What can a radiation measuring device can measure ??
Types of exposure-
 specific types of radiation-
(E.g alpha, beta, gamma,neutron)
 specific levels(ranges) of radiation energy (kv).

6. PERSONAL DOSIMETER
 What is personal dosimeter??
A small radiation monitoring device worn by persons
entering environments that may contain radiation.
 Who should wear personal dosimeter??
 Workers in (emergency/non-emergency) environments
that may contain some radiation.
 Workers in industrial environments were radiations is
used.

7. PERSONAL MONITORING-WHY??
 To ensure dose limits are not exceeded 20msv for
whole body.
 To check that dose is ALARA- (stands for “as low
as reasonably achievable”.)
 Provides documentation in case of ionization
incident/emergency.
 The measure of effective radiation dose- is the millisievert (mSv)

8. TYPES OF PERSONAL MONITORING!!
 Chest badge for whole body monitoring.
(has 2 discs of lithium fluoride)
 Finger monitor:
(Approximately 20mg of lithium fluoride.)

9. WHY LIF?(LITHIUM FLOURIDE)
i. LiF atomic number is 8.1
ii. Which is near to the atomic number of soft tissues
that is 7.4.
iii. Can store energy during exposure to ionising
radiation and subsequently release it as light
when heated.

10. WHERE ARE PERSONAL DOSIMETER ARE
USUALLY WORN??
1. FLAT BADGES ARE USUALLY WORN ON TORSO,AT
THE CHEST LEVEL BUT CAN BE WRON ON THE
FOREARM.
2. RING SHAPED BADGES CAN BE WORN ON THE
FINGER.

11. WHOLE BODY TLD?
 Material - LiF
 Dose - 0.02msv to 10 msv
 Change of
 Interval - standard period of 1,2
or 3 3 month

12. thank you!!