Grazing Incidence Synchrotron Radiation Optics—Correlation of Performance with Metrology

Abstract

The performance of grazing incidence x-ray optical systems is severely compromised by arc-second slope errors arising from surface irregularities in the millimeter spatial period range. It is those errors that limit the performance of most of the aspheric optical systems in use at the National Synchrotron Light Source (NSLS) and it is those errors that are most difficult to control during the polishing process. We present here a set of scanning pinhole measurements made on a grazing incidence cylinder mirror which exhibit typical arc-second beam deflections and then correlate these measurements with surface roughness measurements made with a WYKO optical surface profiler. The average power spectral density (PSD) curve for the surface is computed from the profile measurements, and the various bandwidth-dependent statistical quantities, such as RMS roughness and slope error, which are computed from the PSD curve, are compared with the results from the scanning pinhole measurements.

Towards a new generation long trace profiler LTP-2020: optical design of pencil beam interferometry sensor

“…The first commercial version of the LTP, the LTP-II [7,8], produced by Continental Optical Corp. utilized a singlet lens with a focal length of 1250 mm, designed by Jan Hoogland in 1991 [9]. After Ocean Optics acquired the LTP license in 2000, the optical head was redesigned to be more compact with a lens focal length of about 500 mm [10]. In order to have sufficient degrees of freedom to meet the low distortion requirements, the lens became a more complex cemented doublet.…”