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Using DCM pitch modulation and feedback to improve long term X-ray beam stability

DOI: 10.1088/1742-6596/425/4/042010 DOI Help

Authors: Christopher Bloomer (Diamond Light Source) , Andrew Dent (Diamond Light Source Ltd) , Sofia Diaz-moreno (Diamond Light Source) , Igor Dolbnya (Diamond Light Source) , Ulrik Pedersen (Diamond Light Source) , Guenther Rehm (Diamond Light Source) , Chiu Tang (Diamond Light Source) , Cyrille Thomas (Diamond Light Source)
Co-authored by industrial partner: No

Type: Conference Paper
Conference: 11th International Conference on Synchrotron Radiation Instrumentation
Peer Reviewed: No

State: Published (Approved)
Published: March 2013

Abstract: In this paper we demonstrate significant improvements to the stability of the monochromatic X-ray beam intensity on several beamlines at Diamond, using a modulation of the pitch axis of the DCM with a piezoelectric actuator. The modulation is detected on an intensity diagnostic (e. g. anion chamber) using a software lock-in technique. The detected amplitude and phase are used in a feedback to keep the DCM at the peak of the rocking curve, or any arbitrary position 'off-peak' which might be desired to detune the DCM and reject unwanted harmonics. A major advantage of this software based system is the great flexibility offered, using standard, readily available instrumentation. Measurements of the short and long-term performance of the feedback on several beamlines are presented, and the limitations of such a feedback are discussed.

Journal Keywords: Actuators; Beams; Computer Codes; Diamonds; Feedback; Harmonics; Modulation; Monochromatic Radiation; Neutron Diffraction; Performance; Piezoelectricity; Stability; X Radiation

Subject Areas: Technique Development

Instruments: B16-Test Beamline , I11-High Resolution Powder Diffraction