Experimental Method for Determining the Attenuation by Aluminum Cascade Pipes in the Presence of UF6 Gas During Enrichment Measurements

We previously reported on calculations for a proposed methodof determining the thickness of a pipe in a gas centrifuge enrichmentplant (GCEP) when an empty pipe measurement is notfeasible.1 This method uses an X-ray tube for transmission measurementsand a LaBr3 scintillation detector on the opposite sideof the pipe. Two filters, molybdenum (Mo, K-edge 20.0 keV)and palladium (Pd, K-edge 24.35 keV) are used to transform thebremsstrahlung spectra produced by the X-ray tube into moreuseful spectra each with a sharp peak. The maximum energies ofthe peaks are determined by the K-edges of the filters. The attenuationproperties of the UF6 allow us to determine wall thicknessby looking at the ratio of selected regions of interest (ROIs) ofthe Mo and Pd transmitted spectra. Feasibility studies were performedusing analytical calculations, and filter thicknesses wereoptimized. In order to experimentally validate our attenuationmeasurement method a UF6 source with variable enrichment andpipe thickness was built. We describe the experimental procedureused to verify our previous calculations and present recent results.