| Autor: |
Pablant NA; Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA., Bitter M; Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA., Efthimion PC; Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA., Gao L; Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA., Hill KW; Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA., Kraus BF; Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA., Kring J; Auburn University, Auburn, Alabama 36849, USA., MacDonald MJ; Lawrence Livermore National Laboratory, Livermore, California 94550, USA., Ose N; Lawrence Livermore National Laboratory, Livermore, California 94550, USA., Ping Y; Lawrence Livermore National Laboratory, Livermore, California 94550, USA., Schneider MB; Lawrence Livermore National Laboratory, Livermore, California 94550, USA., Stoupin S; Lawrence Livermore National Laboratory, Livermore, California 94550, USA., Yakusevitch Y; University of California Santa Barbara, Santa Barbara, California 93106, USA. |
| Abstrakt: |
A novel high-resolution x-ray spectrometer for point-like emission sources has been developed using a crystal shape having both a variable major and a variable minor radius of curvature. This variable-radii sinusoidal spiral spectrometer (VR-Spiral) allows three common spectrometer design goals to be achieved simultaneously: 1. reduction of aberrations and improved spectral (energy) resolution, 2. reduction of source size broadening, and 3. use of large crystals to improve total throughput. The VR-Spiral concept and its application to practical spectrometer design are described in detail. This concept is then used to design a spectrometer for an extreme extended x-ray absorption fine structure experiment at the National Ignition Facility looking at the Pb L 3 absorption edge at 13.0352 keV. The expected performance of this VR-Spiral spectrometer, both in terms of energy resolution and spatial resolution, is evaluated through the use of a newly developed raytracing tool, xicsrt. Finally, the expected performance of the VR-Spiral concept is compared to that of spectrometers based on conventional toroidal and variable-radii toroidal crystal geometries showing a greatly improved energy resolution. |
