Reflectometer end station for synchrotron calibrations of Advanced X-ray Astrophysics Facility flight optics and for spectrometric research applications

Journal Article · Wed Feb 01 04:00:00 EST 1995 · Review of Scientific Instruments; (United States)

DOI:https://doi.org/10.1063/1.1145739· OSTI ID:6865181

Graessle, D E; Fitch, J J; Ingram, R; Zhang Juda, J ^[1]; Blake, R L ^[2]

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1. Smithsonian Astrophysical Observatory, Cambridge, Massachusetts 02138-1596 (United States)
2. Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

Preparations have been underway to construct and test a facility for grazing incidence reflectance calibrations of flat mirrors at the National Synchrotron Light Source. The purpose is to conduct calibrations on witness flats to the coating process of the flight mirrors for NASA's Advanced X-ray Astrophysics Facility (AXAF). The x-ray energy range required is 50 eV--12 keV. Three monochromatic beamlines (X8C, X8A, U3A) will provide energy tunability over this entire range. The goal is to calibrate the AXAF flight mirrors with uncertainties approaching 1%. A portable end station with a precision-positioning reflectometer has been developed for this work. We have resolved the vacuum cleanliness requirements to preserve the coating integrity of the flats with the strict grazing-angle certainty requirements placed on the rotational control system of the reflectometer. A precision positioning table permits alignment of the system to the synchrotron beam to within 10 arcsec; the reflectometer's rotational control system can then produce grazing angle accuracy to within less than 2 arcsec, provided that the electron orbit is stable. At 10--12 keV, this degree of angular accuracy is necessary to achieve the calibration accuracy required for AXAF. However the most important energy regions for the synchrotron calibration are in the 2000--3200 eV range, where the [ital M]-edge absorption features of the coating element, iridium, appear, and the 300--700 eV range of the Ir [ital N] edges. The detail versus energy exhibited in these features cannot be traced adequately without a tunable energy source, which necessitates a synchrotron for this work. We present the mechanical designs, motion control systems, detection and measurement capabilities, and selected procedures for our measurements, as well as reflectance data.

• OSTI ID: 6865181
• Journal Information: Review of Scientific Instruments; (United States), Journal Name: Review of Scientific Instruments; (United States) Vol. 66:2; ISSN 0034-6748; ISSN RSINAK
• Country of Publication: United States
• Language: English

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75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ACCELERATORS
BREMSSTRAHLUNG
CALIBRATION
CYCLIC ACCELERATORS
DESIGN
ELECTROMAGNETIC RADIATION
MEASURING INSTRUMENTS
MIRRORS
NSLS
OPTICAL PROPERTIES
PERFORMANCE TESTING
PHYSICAL PROPERTIES
RADIATION SOURCES
RADIATIONS
REFLECTIVITY
SATELLITES
SPECTROMETERS
SURFACE PROPERTIES
SYNCHROTRON RADIATION
SYNCHROTRON RADIATION SOURCES
SYNCHROTRONS
TESTING
X-RAY SPECTROMETERS