Characterization and simulation of soft gamma-ray mirrors for their use with spent fuel rods at reprocessing facilities.

The use of a grazing incidence optic to selectively reflect K-shell fluorescence emission and isotope-specific lines from special nuclear materials is a highly desirable nondestructive analysis method for use in reprocessing fuel environments. Preliminary measurements have been performed, and a simulation suite has been developed to give insight into the design of the x ray optics system as a function of the source emission, multilayer coating characteristics, and general experimental configurations. The experimental results are compared to the predictions from our simulation toolkit to illustrate the ray-tracing capability and explore the effect of modified optics in future measurement campaigns.

Reflective multilayer optic as hard X-ray diagnostic on laser-plasma experiment.

A multilayer-based optic was tested for use as an X-ray diagnostic on a laser-plasma experiment. The multilayer optic was employed to selectively pass X-rays between 55 and 100 keV. An order of magnitude improvement in signal-to-noise ratio is achieved compared to a transmission crystal spectrometer. A multilayer response model, taking into account the source size and spectral content, is constructed and the outlook for application above 500 keV is briefly discussed. LLNL-JRNL-664311.

The Baylor Video Acuity Tester.

A device has been developed that offers many advantages not available with traditional visual acuity testing methods. The Baylor Video Acuity Tester (BVAT) produces randomized targets, size selectable at electronic speeds for testing even in normal ambient room light. Comparisons of the BVAT with the Project-O-Chart (American Optical Corp, Southbridge, Mass) on 60 subjects yield correlations of .93 and .95. A test-retest correlation of the BVAT of .88 was found.

A semi-automated instrument for determination of acuity threshold.

A device has been constructed that permits rapid, repeatable measures of visual acuity while minimizing many of the patient and examiner errors in subjective acuity testing. The Baylor acuity meter utilizes digital logic circuitry to implement a carefully controlled psychophysical "staircase" testing procedure in a small portable unit. Comparisons of the acuity meter with conventional measurement techniques on 51 subjects yield correlations of +.74 and +.81. A test-retest correlation of +.96 was found.