THREE-DIMENSIONAL REAL-TIME NEUTRON DOSIMETRY SYSTEM

A DEVICE AMD METHOD FOR MEASURING THREE-DIMENSIONAL NEUTRON DISE DISTRIBUTION IN-PHANTOMS ON A REAL-TIME BASIS WILL BE DEVELOPED. THIS METHOD OFFERS THE ADVANTAGES OF NEUTRON DETECTORS WHICH ARE TISSUE-EQUIVALENT AND MINIMIZE DISTURBANCE TO NEUTRON SCATTERING WITHIN A TUSSUE-EQUIVALENT PHANTOM. BY PROPER SELECTION OF HIGH VAPOR-PRESSURE LIQUID, MOCROSPHERE (BUBBLE) DIAMETER AND THE LIQUID/GET TERPERATURE, THE INSTRUMENT CAN BE USED TO PERFORM NEUTRON DOSE DISTRIBUTIONS WITHIN INTERVALS OVER THE ENERGY RANGE FROM 1 KEV TO 40 MEV. THE INSTRUMENT IS EXPECTED TO PROVIDE LINEAR RESPONSE OVER THE ENERGY RANGES FROM 1 KEV TO 100 KEV AND 60 KEV TO 40 MEV AND BE APABLE OF ACCURATELY RECORDING DOSE LEVELS AS LOW AS 0.01 CGY. THE TECHNIQUE ALLOWS INDIVIDUAL ONE-DIMENSIONAL NEUTRON DOSIMETER RODS TO BE CONFIGURED INTO AN ARRAY SUITABLE FOR DETAILED MAPPING OF NEUTRON DOSE DISTRUBUTION FOR USE IN TREATMENT PLANNING. THE PHASE I PROGRAM WILL INCLUDE EXPERIMENTAL VERIFICATION OF ACCURACY OF DETECTION OF NEUTRON DOSE POSITION. THE ACCURACY OF PREDICTING POSITION OF NEUTRON-INDUCED BUBBLE FORMATION IN SUPERHEATED LIQUID DISPERSIONS USING THIS TECHNIQUE IS EXPECTED TO BE WITHIN 1-2 MM.