Safeguards Analytical Laboratory
X-Ray Fluorescence Spectrometer for Screening Environmental Samples
Environmental swipe samples contain unknown amounts of the elements of interest (for example U and Pu). X-ray fluorescence spectrometry is used to detect microgram amounts of U, Pu or other elements of interest on the surface of swipe samples. The sample is placed on the spectrometer where it is irradiated by X-rays from a 20mCi 109Cd source which excite the fluorescent X-rays of elements present on the swipe. The fluorescent X-rays are detected by a 100mm2 Si(Li) detector placed under the radioisotope source. Counting is performed for 10 minutes and the spectrum is then evaluated to determine the amount of U or other elements present. The detection limit for U is approximately 1 microgram/cm2, with an accuracy of about 10-20% relative. This screening method is completely non-invasive because the subsample can be measured inside its double plastic bagging.
X-Ray Fluorescence Spectrometer