RADIATION PROBE SYSTEM AND METHOD

摘要

A radiation probe system and method incorporating adaptive gamma radiation background subtraction for enhanced radiation detection capability is disclosed. The system and method are generally applicable to radiation “frisking” applications in which the contamination area may have high gamma radiation background levels that normally would result in loss of contamination radiation detection accuracy. Readings from a background radiation detector (BRD) are subtracted from a contamination radiation detector (CRD) to determine a count rate solely associated with contamination. A background subtraction factor (BSF) is used to scale the BRD subtraction and is automatically adjusted based on environmental conditions. A smoothing algorithm is used to increase/decrease the BRD and/or CRD acquisition times to account for signal variations in BRD/CRD measurement readings. The system and method provide for lower limit of detection (LLD) radiation levels that are below that of conventional radiation detectors.

主权项

1. A radiation probe system comprising:
(a) background radiation detector (BRD); (b) contamination radiation detector (CRD); (c) proximity sensor (PRS); (d) operator audible alarm (OAA); (e) operator visual indicator (OVI); (f) computing control device (CCD); and (g) radiation probe enclosure (RPE); wherein said RPE is configured to mechanically couple said BRD, said CRD, said PRS, and said CCD in said RPE; said BRD is positioned behind said CRD such that gamma radiation external to said RPE first passes through said CRD before detection by said BRD; said PRS is configured to determine the proximity of a radiation source to said RPE; said BRD is configured to detect gamma radiation from said radiation source; said CRD is configured to detect alpha, beta, and gamma radiation from said radiation source; said CCD is configured to read background radiation counts (BRC) from said BRD; said CCD is configured to read contamination radiation counts (CRC) from said CRD; said CCD is configured to calculate a radiation background count (RBC) by processing said BRC to estimate static background gamma radiation; said CCD is configured to calculate a background subtraction factor (BSF) based on said RBC; said CCD is configured to calculate a net measured radiation (NMR) value by subtracting from said CRC the product of said RBC and said BSF; said CCD is configured to periodically perform a coherence test of said NMR to determine the statistical correctness of said BSF; said CCD is configured to calculate a radiation detection threshold (RDT) based on said RBC; and said CCD is configured to activate said OAA and said OVI based on the values of said NMR, said RDT, and a predetermined alarm threshold value (ATV).