Title: First Indirect X-Ray Imaging Tests With An 88-mm Diameter Single Crystal,
Abstract: Using the 1-BM-C beamline at the Advanced Photon Source (APS), we have
performed the initial indirect x-ray imaging point-spread-function (PSF) test
of a unique 88-mm diameter YAG:Ce single crystal of only 100-micron thickness.
The crystal was bonded to a fiber optic plate (FOP) for mechanical support and
to allow the option for FO coupling to a large format camera. This
configuration resolution was compared to that of self-supported 25-mm diameter
crystals, with and without an Al reflective coating. An upstream monochromator
was used to select 17-keV x-rays from the broadband APS bending magnet source
of synchrotron radiation. The upstream, adjustable Mo collimators were then
used to provide a series of x-ray source transverse sizes from 200 microns down
to about 15-20 microns (FWHM) at the crystal surface. The emitted scintillator
radiation was in this case lens coupled to the ANDOR Neo sCMOS camera, and the
indirect x-ray images were processed offline by a MATLAB-based image processing
program. Based on single Gaussian peak fits to the x-ray image projected
profiles, we observed a 10.5 micron PSF. This sample thus exhibited superior
spatial resolution to standard P43 polycrystalline phosphors of the same
thickness which would have about a 100-micron PSF. This single crystal
resolution combined with the 88-mm diameter makes it a candidate to support
future x-ray diffraction or wafer topography experiments.