Emily L Church

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Surface finish measurements are usually fitted to models of the finish correlation function which are parametrized in terms of root-mean-square roughnesses, delta, and correlation lengths, l. Highly finished optical surfaces, however, are frequently better described by fractal models, which involve inverse power-law spectra and are parametrized by spectral(More)
We describe methods of predicting the degradation of the performance of a simple imaging system in terms of the statistics of the shape errors of the focusing element and, conversely, of specifying those statistics in terms of requirements on image quality. Results are illustrated for normal-incidence, x-ray mirrors with figure errors plus conventional(More)
Modifications of the long trace profiler at the Advanced Photon Source at Argonne National Laboratory have significantly improved its accuracy and repeatability for measuring the figure of large flat and long-radius mirrors. Use of a Dove prism in the reference beam path corrects phasing problems between mechanical errors and thermally induced system(More)
I. INÎRODUCTION Abstract. This paper compares two methods of measuring the fin¡sh of precision machined optical surfaces: the older, well-established mechanicalstylus gauge and a recently developed optical gauge using interference microscopy. Results are found to be in good quantitative agreement for both random and periodic surface features, provided that(More)
OBJECTIVE To evaluate the agreement between the current National Healthcare Safety Network (NHSN) definition for ventriculitis and others found in the literature among patients with an external ventricular drain (EVD) DESIGN Retrospective cohort study from January 2009 to December 2014 SETTING Neurology and neurosurgery intensive care unit of a large(More)
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