title: Rapid in situ X-ray position stabilization via extremum seeking feedback.
abstract: X-ray beam stability is crucial for acquiring high-quality data at synchrotron beamline facilities. When the X-ray beam and defining apertures are of similar dimensions, small misalignments driven by position instabilities give rise to large intensity fluctuations. This problem is solved using extremum seeking feedback control (ESFC) for in situ vertical beam position stabilization. In this setup, the intensity spatial gradient required for ESFC is determined by phase comparison of intensity oscillations downstream from the sample with pre-existing vertical beam oscillations. This approach compensates for vertical position drift from all sources with position recovery times <6 s and intensity stability through a 5 µm aperture measured at 1.5% FWHM over a period of 8 hours.
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, BLDG 436, Argonne, IL 60439, USA.
authors.forename: S
authors.initials: S
authors.lastname: Zohar
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, BLDG 436, Argonne, IL 60439, USA.
authors.forename: N
authors.initials: N
authors.lastname: Venugopalan
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, BLDG 436, Argonne, IL 60439, USA.
authors.forename: D
authors.initials: D
authors.lastname: Kissick
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, BLDG 436, Argonne, IL 60439, USA.
authors.forename: M
authors.initials: M
authors.lastname: Becker
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, BLDG 436, Argonne, IL 60439, USA.
authors.forename: S
authors.initials: S
authors.lastname: Xu
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, BLDG 436, Argonne, IL 60439, USA.
authors.forename: O
authors.initials: O
authors.lastname: Makarov
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, BLDG 436, Argonne, IL 60439, USA.
authors.forename: S
authors.initials: S
authors.lastname: Stepanov
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, BLDG 436, Argonne, IL 60439, USA.
authors.forename: C
authors.initials: C
authors.lastname: Ogata
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, BLDG 436, Argonne, IL 60439, USA.
authors.forename: R
authors.initials: R
authors.lastname: Sanishvili
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, BLDG 436, Argonne, IL 60439, USA.
authors.forename: R F
authors.initials: RF
authors.lastname: Fischetti
mesh_terms: D017356:Synchrotrons; D014965:X-Rays
keywords: X-rays; extremum seeking; feedback; stabilization