Double-edge scan wavefront metrology and its application in crystal diffraction wavefront measurements.
J Synchrotron Radiat
; 31(Pt 5): 1146-1153, 2024 Sep 01.
Article
em En
| MEDLINE
| ID: mdl-39073994
ABSTRACT
Achieving diffraction-limited performance in fourth-generation synchrotron radiation sources demands monochromator crystals that can preserve the wavefront across an unprecedented extensive range. There is an urgent need for techniques of absolute crystal diffraction wavefront measurement. At the Beijing Synchrotron Radiation Facility (BSRF), a novel edge scan wavefront metrology technique has been developed. This technique employs a double-edge tracking method, making diffraction-limited level absolute crystal diffraction wavefront measurement a reality. The results demonstrate an equivalent diffraction surface slope error below 70â
nrad (corresponding to a wavefront phase error of 4.57% λ) r.m.s. within a nearly 6â
mm range for a flat crystal in the crystal surface coordinate. The double-edge structure contributes to exceptional measurement precision for slope error reproducibility, achieving levels below 15â
nrad (phase error reproducibility < λ/100) even at a first-generation synchrotron radiation source. Currently, the measurement termed double-edge scan (DES) has already been regarded as a critical feedback mechanism in the fabrication of next-generation crystals.
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MEDLINE
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Ano de publicação:
2024
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Article