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INVESTIGATION OF METHODS FOR IMPROVING THE THERMOLUMINES- CENCE `PROPERTIES OF THIN DOSEMETERS FOR SPECIFIC APPLICATIO NS TO BETA AND LOW ENERGY PHOTON DOSIMETRY

Objective

OBJECTIVES:
1. TO INVESTIGATE THEIR PROPERTIES AND PREPARATIONAL PARAMETERS OF NEW HIGH SENSITIVITY THERMOLUMINESCENT MATERIALS
2. TO INVESTIGATE THE INCORPORATION OF THOSE MATERIALS INTO THIN (OR DOSIMETRICALLY THIN) DOSEMETERS (E.G. CARBON-LOADED DETECTORS) FOR USE IN BETA DOSIMETRY, AND
3. TO STUDY THE ANGULAR AND FIELD DEPENDENCES OF SUCH BETA DOSEMETERS IN MIXED BETA-GAMMA RADIATION FIELDS.

IN ORDER TO FIND SOLUTIONS TO SOME OF THE DIFFICULTIES IN PRODUCING ROBUST DETECTORS FOR ROUTINE BETA DOSIMETRY, IT IS PROPOSED TO INVESTIGATE THE POSSIBLE INCORPORATION OF A HIGH SENSITIVITY TISSUE EQUIVALENT MATERIAL (SUCH AS LIF; MG, CU, P) INTO A PHYSICALLY THICK DOSEMETER WHICH APPEARS DOSIMETRICALLY THIN (E.G. A CARBON-LOADED PTFE DISC (0.4 MM THICK)).

THIS REQUIRES A BETTER UNDERSTANDING OF THE GROWTH AND PREPARATIONAL PARAMETERS OF THERMOLUMINESCENT MATERIALS IN GENERAL AND OF LIF; MG, CU, P IN PARTICULAR. THE LATTER MATERIAL AS CURRENTLY PRODUCED CANNOT BE ANNEALED AT HIGH TEMPERATURES WITHOUT LOSS OF SENSITIVITY, UNLIKE MATERIAL PRODUCED EARLIER WHICH UNFORTUNATELY SUFFERED FROM FADING OF THE THERMOLUMINESCENCE SIGNAL.

LIF: MG, CU, P IS FORTY TIMES MORE SENSITIVE THAN STANDARD LIF: MG, TI AND HAS AN ENERGY INDEPENDENT RESPONSE TO PHOTONS TO WITHIN +/- 20 %. THEREFORE, THIS NEW MATERIAL HAS GOOD POTENTIAL FOR MEASUREMENT IN MIXED BETA-PHOTON RADIATION FIELDS. THE USE OF CARBON PRODUCES DOSIMETRICALLY THIN DETECTORS BECAUSE ONLY THE LIGHT EMISSION FROM THE UPPER LAYERS OF THE PARTIALLY OPAQUE MATERIAL IS DETECTED.

STUDIES WILL ALSO BE CARRIED OUT ON THE ANGULAR DEPENDENCE OF RESPONSE OF THESE DOSEMETERS IN MIXED RADIATION FIELDS.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

NATIONAL RADIOLOGICAL PROTECTION BOARD (NRPB)
Address
Chilton
OX11 0RQ Didcot
United Kingdom