Evaluation of HgI/sub 2/ detectors for lead detection in paint

A laboratory study of HgI/sub 2/ spectrometers used for in situ determination of lead on painted surfaces was conducted. /sup 109/Cd and /sup 57/Co isotopes were used to excite lead characteristic X-rays from samples. The energy resolution of HgI/sub 2/ detectors in the energy region corresponding to lead K X-rays was measured. An energy resolution of 880 eV full-width half-maximum (FWHM) for the 60-keV line from a /sup 241/Am source was obtained. Measurements using thin film standards ranging from 0.5 mg Pb/cm/sup 2/ to 2 mg Pb/cm/sup 2/ were conducted. The detection limits the accuracy and the precision of the measurements were estimated. Based upon a comparison of the results obtained with the performance of existing detector technology, HgI/sub 2/ detectors seem to be the best solution for hand-held X-ray fluorescence (XRF) lead analyzers.<
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