A comparison of the performance of a spherical and elliptical mirror in the grasshopper monochromator is presented. The problem was studied by ray tracing and then tested using visible (lgr;=633 nm) laser light. Calculations using ideal optics yield an improvement in flux by a factor of up to 2.7, while tests with visible light show an increase by a factor of 5 because the old spherical mirror is compared to a new, perfect elliptical one. The FWHM of the measured focus is 90 mgr;m with a spherical mirror, and 25 mgr;m with an elliptical one. Elliptical mirrors have been acquired and are now being installed in the two grasshoppers at SSRL.
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