SENSITIVE AND SELECTIVE DETECTION OF PLUTONIUM USING HIGH RESOLUTION X-RAY

High Resolution X-ray (hiRX) offers sensitive and selective detection of actinide elements found in spent nuclear fuel dissolver solutions. Monochromatic wavelength dispersive X-ray fluorescence (MWDXRF) technology is the basis for hiRX. The technical foundation of hiRX is the use of doubly curved crystal (DCC) optics for both excitation and detection of the targeted analyte. This work will highlight the capabilities of a prototype hiRX instrument designed for actinide characterization specifically plutonium. The excitation will be accomplished using the Rh?a line at 20.214 keV. The ?a line is selected using a DCC that transmits only the Rh?a line to the sample. The coupled DCC and low power (50W) x-ray tube provides a monochromatic excitation beam. The Rh offers efficient excitation of the target actinide La lines (Th-Cm). The monochromatic excitation lowers the background compared with bremsstrahlung excitation which is typically used. The emitted x-ray fluorescence for the prescribed analyte plutonium is selected using another DCC specifically passing the PuLa line at 14.279 keV. A silicon drift detector is used to measure the transmitted PuLa x-rays. The detector DCC further reduces the background and selectively passes only the analyte X-ray fluorescence with a bandpass of around 200 eV. This instrument has the potential to offer direct measurement of the Pu concentration in spent nuclear fuel dissolver solutions with improved accuracy over conventional gamma, neutron and hybrid K-edge measurements. The combination of low sample volume, high sensitivity and detection selectivity offers a range of potential applications for Pu and actinide measurements for safeguards operations