EVALUATION OF HGI2 DETECTORS FOR LEAD DETECTION IN PAINT

We have conducted a laboratory study of HgI2 spectrometers used for in-situ determination of lead on painted surfaces. Cd-109 and Co-57 isotopes have been used to excite lead characteristic x-rays from samples. The energy resolution of HgI2 detectors in the energy region corresponding to lead K x-rays has been measured. An energy resolution of 880 eV (FWHM) for the 60 keV line from an Am-241 source has been obtained. Measurements using thin film standards ranging from 0.5 mg Pb/cm2 to 2 mg Pb/cm2 have been conducted. Detection limits, accuracy and precision of the measurements have been estimated. Based upon a comparison of the results that we have obtained with the performance of existing detector technology, the HgI2 detectors seem to be the best solution for handheld XRF lead analyzers.