Thermoluminescent Dosimeters

Thermoluminescent Dosimeters

Write short note on TLD badges.
or
Write short note on TLD
Answer. The full form of TLD badge is Thermoluminescence Dosimeter badge.

• TLD badge is used for measurement of actual dose received by operator or patient due to radiography or radiotherapy exposure and are personal monitoring devices.
• It is easily placed over the body since its size is very small.

“Understanding the role of thermoluminescent dosimeters in radiation safety: Q&A explained”

Thermoluminescence Dosimeter badge Structure 

• TLD badge in India consists of TLD card holder cassette which is made up of high impact plastic, TLD card has nickel plated aluminum plate consisting of three symmetrical holes in which calcium sulphate embedded Teflon disks are inserted.
• These teflon disks are clipped on aluminum card which is loaded in cassette and consists of three filters, i.e. open region, copper and aluminum.

“Importance of studying thermoluminescent dosimeters for better radiation monitoring: Questions explained”

Thermoluminescence Dosimeter badge Principle

• When phosphorous is irradiated the X-ray energy is absorbed and secondary electrons are emitted.
• Secondary electrons create holes in filled zone by lifting electrons to conduction band.
• Here the electrons fall back in traps in metastable state where they held up.
• When phosphorus is heated at 2000 to 3000°C the trapped electrons acquire energy to escape back to conduction band.
• From conduction band, the electrons fall back to fill holes in filled zone when they recombine visible light is produced known as thermoluminescence.

“Common challenges in using thermoluminescent dosimeters effectively: FAQs provided”

Thermoluminescence Dosimeter badge Reader

• Equipment which heat the exposed material and measure emitted light is known as TLD reader.
• Reading produced by TLD reader is used as a measure of absorbed dose to which material is subjected.
• It consists of three parts, i.e. heater, photomultiplier tube and electronic system.

TLD detector

“Steps to explain how thermoluminescent dosimeters work: Energy trapping vs light emission: Q&A guide”

Wearing of TLD Badge

• Chest badge consists of metallic clip which is to be worn outside the clothes. It should be kept below lead apron.
• Wrist badges consist of snap for attachment.

Thermoluminescence Dosimeter badge Indications

• In radiotherapy
• In radiodiagnosis
• For personal monitoring

Thermoluminescence Dosimeter badge Advantages

• It is chemically inert.
• Size is small and light in weight.
• Reusable
• Provide accurate readings
• It is economical
• Can be used for various range of radiation qualities.

“Role of crystal structure in thermoluminescent dosimeters: Questions answered”

Thermoluminescence Dosimeter badge Disadvantages

• Provide limited information.
• Dose gradients are not detected.
• Records are not permanent.