MEASUREMENT OF RESIDUAL RADIOACTIVE CONTAMINATION BY 2-D LASER HEATED TLD

A FEASIBILITY STUDY OF USING DEVELOPED TECHNOLOGY CENTERED ON LASER HEATING OF VERY THIN THERMOLUMINESCENCE DOSIMETRY (TLD) ARRAYS FOR THE PURPOSE OF SURVEYING DECOMMISIONED AND/OR DEACTIVATED FACILITIES FOR RESIDUAL LOW ACTIVITY, SHORT RANGE RADIOACTIVE CONTAMINATION IS PROPOSED. DETECTION OF SHORT RANGE (ALPHA AND LOW BETA) PARTICLES EMITTED FROM AREAS OF LOW ACTIVITY IS DIFFICULT WITH CURRENTLY AVAILABLE DEVICES USEDIN SWEEP MODE FOR AREA SURVEYS. THOROUGH, HIGH SENSITIVITY SURVEY COVERAGE IS BEST ACCOMPLISHED BY THIN, INTEGRATING RADIATION DETECTORS. THE SYSTEM TO BE STUDIED PROVIDES FOR A HIGH DEGREE OF SURFACE COVERAGE BY A PASSIVE ARRAY OF 40 M THICK TLD ELEMENTS (>10,000 PER SQUARE FT) WHICH CAN BE LEFT IN CONTACT WITH THE SURVEY AREA FOR HOURS OR DAYS. THE THIN TLD ELEMENTS ARE PERFECTLY MATCHED FOR DETECTION OF ALPHA PARTICLE EMISSIONS, AND ARE RELATIVELY INSENSITIVE TO X- AND -RAY BACKGROUNDS. THE ARRAYS ARE EVALUATED IN A LASER-BASED TLD READER. THE THIN, FLEXIBLE SUBSTRATES ALLOW FOR ARRAY CONFORMATION WITH REGULAR SURFACES, FOR USE IN OR ON PIPES, ETC. SENSITIVITY ADEQUATE FOR USE WITH ALPHA ACTIVITIES BELOW 200 DPM/100 SQUARE CM IS ANTICIPATED. THE RESULTS SHOULD PROVE BENEFICIAL FOR DECOMMISSION RESIDUAL CONTAMINATION COMPLIANCE.