Uranium and plutonium solution assays by transmission-corrected X-ray fluorescence spectrometry

An x-ray fluorescence analysis technique was developed for uranium and plut onium solutions, which compensates for variations in the absorption of the exciting gamma rays and fluorescent x-rays, Co-57 is used to excite efficie ntly the K lines of the elements, and a mixed Co-57 plus Gd-153 transmissio n source is used to correct for variations in absorption. The absorption co rrection is a unique feature of the technique which permits accurate calibr ation with a single solution standard and the measurement of a wide range o f concentrations (up to 300 g l(-1)). Without this correction procedure, up to six solution standards are required to correct for non-linearity over t his concentration range. In addition, other elements present in the specime ns and not present in the standards would otherwise reduce the accuracy or even invalidate the analyses. Specially designed equipment incorporates a p lanar intrinsic germanium detector, excitation and transmission radioisotop es and specimen holder. The apparatus can be inserted into a rubber glove o f a glove-box, keeping the apparatus outside and the solutions inside the g love-box, thereby protecting the user and the equipment from possible conta mination, This technique will be tested at the Bochvar Institute of Inorgan ic Materials in Moscow for possible use in the Russian complex of nuclear f acilities. This is part of a cooperative program between laboratories in th e USA and Russia to strengthen systems of nuclear materials protection, con trol and accountability (MPC&A) in both countries. A part of this program i s to measure accurately and track inventories of materials, hence the need for good non-destructive analytical techniques. Copyright (C) 1999 John Wil ey & Sons, Ltd.