Browsing by Author "Kawai, T."

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    Design Of A High-Temperature And High-Pressure Liquid Flow Cell For X-Ray Absorption Fine Structure Measurements Under Catalytic Reaction Conditions
    Kawai, T.; Chun, W. J.; Asakura, K.; Koike, Y.; Nomura, M.; Bando, K. K.; Oyama, Shigeo Ted; Sumiya, H. (AIP Publishing, 2008-01-01)
    The design and performance of a new high-pressure and high-temperature cell for measurement of x-ray absorption fine structure (XAFS) spectra of solid catalysts working in a flowing liquid are presented. The cell has flat, high-purity sintered cubic boron nitride (c-BN) windows which can tolerate high temperature (900 K) and high pressure (10 MPa). The c-BN is a new material which has the highest tensile strength, second only to diamond, and is also chemically and thermally stable. The use of the cell is demonstrated for measurements of PtPd/Al(2)O(3) and Ni(2)P/SiO(2) hydrodesulfurization catalysts at reaction conditions. A technique called delta chi (Delta chi), involving determining the difference between XAFS spectra of the sample at reaction conditions and the bare sample, is introduced. (c) 2008 American Institute of Physics.
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    First Measurement of the Neutron beta Asymmetry with Ultracold Neutrons
    Pattie, R. W.; Anaya, J.; Back, H. O.; Boissevain, J. G.; Bowles, T. J.; Broussard, L. J.; Carr, Rachel E.; Clark, D. J.; Currie, S.; Du, S.; Filippone, B. W.; Geltenbort, P.; Garcia, A.; Hawari, A.; Hickerson, K. P.; Hill, R.; Hino, M.; Hoedl, S. A.; Hogan, G. E.; Holley, A. T.; Ito, T. M.; Kawai, T.; Kirch, K.; Kitagaki, S.; Lamoreaux, S. K.; Liu, C. Y.; Liu, J.; Makela, M.; Mammei, R. R.; Martin, J. W.; Melconian, D.; Meier, N.; Mendenhall, M. P.; Morris, C. L.; Mortensen, R.; Pichlmaier, A.; Pitt, M. L.; Plaster, B.; Ramsey, J. C.; Rios, R.; Sabourov, K.; Sallaska, A. L.; Saunders, A.; Schmid, R.; Seestrom, S. J.; Servicky, C.; Sjue, S. K. L.; Smith, D.; Sondheim, W. E.; Tatar, E.; Teasdale, W.; Terai, C.; Tipton, B.; Utsuro, M.; Vogelaar, R. Bruce; Wehring, B. W.; Xu, Y. P.; Young, A. R.; Yuan, J.; Ucna Collaboration (American Physical Society, 2009-01-09)
    We report the first measurement of an angular correlation parameter in neutron beta decay using polarized ultracold neutrons (UCN). We utilize UCN with energies below about 200 neV, which we guide and store for similar to 30 s in a Cu decay volume. The interaction of the neutron magnetic dipole moment with a static 7 T field external to the decay volume provides a 420 neV potential energy barrier to the spin state parallel to the field, polarizing the UCN before they pass through an adiabatic fast passage spin flipper and enter a decay volume, situated within a 1 T field in a 2 x 2 pi solenoidal spectrometer. We determine a value for the beta-asymmetry parameter A(0) = -0.1138 +/- 0.0046 +/- 0.0021.