Comparison of slope and height profiles for flat synchrotron x-ray mirrors measured with a long trace profiler and a Fizeau interferometer.

Conference · Mon Jan 01 04:00:00 EST 2007

OSTI ID:970373

Qian, J; Assoufid, L; Macrander, A

Long trace profilers (LTPS) have been used at many synchrotron radiation laboratories worldwide for over a decade to measure surface slope profiles of long grazing incidence x-ray mirrors. Phase measuring interferometers (PMIs) of the Fizeau type, on the other hand, are being used by most mirror manufacturers to accomplish the same task. However, large mirrors whose dimensions exceed the aperture of the Fizeau interferometer require measurements to be carried out at grazing incidence, and aspheric optics require the use of a null lens. While an LTP provides a direct measurement of ID slope profiles, PMIs measure area height profiles from which the slope can be obtained by a differentiation algorithm. Measurements of the two types of instruments have been found by us to be in good agreement, but to our knowledge there is no published work directly comparing the two instruments. This paper documents that comparison. We measured two different nominally flat mirrors with both the LTP in operation at the Advanced Photon Source (a type-II LTP) and a Fizeau-type PMI interferometer (Wyko model 6000). One mirror was 500 mm long and made of Zerodur, and the other mirror was 350 mm long and made of silicon. Slope error results with these instruments agree within nearly 100% (3.11 {+-} 0.15 {micro}rad for the LTP, and 3.11 {+-} 0.02 {micro}rad for the Fizeau PMI interferometer) for the medium quality Zerodur mirror with 3 {micro}rad rms nominal slope error. A significant difference was observed with the much higher quality silicon mirror. For the Si mirror, slope error data is 0.39 {+-} 0.08 {micro}rad from LTP measurements but it is 0.35 {+-} 0.01 {micro}rad from PMI interferometer measurements. The standard deviations show that the Fizeau PMI interferometer has much better measurement repeatability.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: SC
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 970373
• Report Number(s): ANL/XSD/CP-60020
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

43 PARTICLE ACCELERATORS
ADVANCED PHOTON SOURCE
APERTURES
DIMENSIONS
INTERFEROMETERS
MANUFACTURERS
MIRRORS
OPTICS
SILICON
SYNCHROTRON RADIATION
SYNCHROTRONS