Ultra-Low Field NMR for Detection and Characterization of 235 UF6

Year
2009
Author(s)
Michelle A. Espy - Los Alamos National Laboratory
Per E. Magnelind - Los Alamos National Laboratory
Andrei N. Matlashov - Los Alamos National Laboratory
Algis V. Urbaitis - Los Alamos National Laboratory
Petr L. Volegov - Los Alamos National Laboratory
Abstract
We have demonstrated the first ultra-low field (ULF) nuclear magnetic resonance measurements of uranium hexafluoride (UF6), both depleted and 70% enriched, which is used in the uranium enrichment process. A sensitive non-invasive detection system would have an important role in non-proliferation surveillance. A two-frequency technique was employed to remove the transients induced by rapidly switching off the 50 mT pre-polarization field. A mean transverse relaxation time T2 of 24 ms was estimated for the un-enriched UF6 sample measured at a mean temperature of 80 ºC. Nuclear magnetic resonance at ULF has several advantages including the ability to measure through metal, such as pipes, and simple magnetic field generation hardware. We present here recent data and discuss the potential for non-proliferation monitoring of enrichment and flow velocity.