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

Bloomer, Chris; Dent, A. J.; Díaz‐Moreno, Sofía; Dolbnya, Igor P.; Pedersen, U.; Rehm, Guenther; Tang, Chin-I; Thomas, Caithleann

doi:10.1088/1742-6596/425/4/042010

Cited by 5 publications

(7 citation statements)

References 3 publications

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“…Extremum-seeking control (Krstić & Wang, 2000;Proux et al, 2006) uses a 'perturb and observe' scheme in which the mechanism controlling the intensity is continuously perturbed and the variation in intensity is measured to determine the location of the maximum and/or direction to move towards the maximum position. The perturb and observe scheme has been implemented in hardware in a number of different ways, but at its core a sine-wave oscillation is used to drive the intensity perturbation by oscillating a monochromator crystal, and a phase-lock loop or phase measurement observes the intensity variation to determine the direction and magnitude (Zohar et al, 2016;Bloomer et al, 2013;Stoupin et al, 2010;Renevier et al, 2003). Beam position can also be used as an indicator of monochromator alignment and is controlled using piezo actuators in the monochromator.…”

Section: Optimization Of Beam Intensity and Positionmentioning

confidence: 99%

“…Implementations of intensity-based schemes, while successful, are often localized to a beamline or facility, or implemented for specific hardware, which can hamper more general adoption. Schemes developed at Diamond (Bloomer et al, 2013), for example, were not straightforward to implement on different beamlines due to differences in control system architectures (e.g. older VME versus newer Ethercat).…”

Section: Optimization Of Beam Intensity and Positionmentioning

confidence: 99%

See 1 more Smart Citation

Beam and sample movement compensation for robust spectro-microscopy measurements on a hard X-ray nanoprobe

Quinn¹,

Gomez-Gonzalez²,

Cacho-Nerin³

et al. 2021

J Synchrotron Radiat

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Static and in situ nanoscale spectro-microscopy is now routinely performed on the Hard X-ray Nanoprobe beamline at Diamond and the solutions implemented to provide robust energy scanning and experimental operation are described. A software-based scheme for active feedback stabilization of X-ray beam position and monochromatic beam flux across the operating energy range of the beamline is reported, consisting of two linked feedback loops using extremum seeking and position control. Multimodal registration methods have been implemented for active compensation of drift during an experiment to compensate for sample movement during in situ experiments or from beam-induced effects.

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Section: Optimization Of Beam Intensity and Positionmentioning

confidence: 99%

Section: Optimization Of Beam Intensity and Positionmentioning

confidence: 99%

Beam and sample movement compensation for robust spectro-microscopy measurements on a hard X-ray nanoprobe

Quinn¹,

Gomez-Gonzalez²,

Cacho-Nerin³

et al. 2021

J Synchrotron Radiat

View full text Add to dashboard Cite

show abstract

“…Beam stabilization can also be achieved by steering the electron beam orbit via the storage ring magnets (Chrin et al , 2008), also at higher frequencies (Nakamura & Katsura, 1993). Moreover, feedback on monochromator crystal angular settings can be used to stabilize the X-ray beam energy and intensity (Bloomer et al , 2013, van Silfhout et al , 2014, Krolzig et al , 1984), and in principle the stabilization of the full beam profile is possible.…”

Section: X-ray Source Optics and Diagnosticsmentioning

confidence: 99%

Current advances in synchrotron radiation instrumentation for MX experiments

Owen

Juanhuix

Fuchs

2016

Archives of Biochemistry and Biophysics

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Following pioneering work 40 years ago, synchrotron beamlines dedicated to macromolecular crystallography (MX) have improved in almost every aspect as instrumentation has evolved. Beam sizes and crystal dimensions are now on the single micron scale while data can be collected from proteins with molecular weights over 10 MDa and from crystals with unit cell dimensions over 1000 Å. Furthermore it is possible to collect a complete data set in seconds, and obtain the resulting structure in minutes. The impact of MX synchrotron beamlines and their evolution is reflected in their scientific output, and MX is now the method of choice for a variety of aims from ligand binding to structure determination of membrane proteins, viruses and ribosomes, resulting in a much deeper understanding of the machinery of life. A main driving force of beamline evolution have been advances in almost every aspect of the instrumentation comprising a synchrotron beamline. In this review we aim to provide an overview of the current status of instrumentation at modern MX experiments. The most critical optical components are discussed, as are aspects of endstation design, sample delivery, visualization and positioning, the sample environment, beam shaping, detectors and data acquisition and processing.

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“…'Slow' motions are resolved by the detector and are therefore observable as a variation in the photon beam intensity or position (Farvacque, 1998). Extensive research has been conducted into the stability of the electron beam, improving the emittance stability, orbit stability and source point motion as it passes through the insertion device (Rehm, 2012). However intensity changes are not solely due to the electron beam but also the X-ray beam as it propagates through the beamline.…”

Section: Introductionmentioning

confidence: 99%

“…Without mitigation, the impact of mechanical vibrations could become the limiting factor for full exploration of new generation low-emittance synchrotron beams (Grizolli et al, 2019). Current mitigation techniques can include feedback systems to correct X-ray beam drift, mechanical interventions to reduce the transmission of vibration from external sources through to the optical elements or installation of passive ISSN 1600-5775 magnetic damping systems to damp vibrations entirely (Bloomer et al, 2012;Yamazaki et al, 2013;Diez-Jimenez et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Modelling the effects of optical vibrations on photon beam parameters using ray-tracing software

Houghton

Bloomer

Alianelli

2021

J Synchrotron Radiat

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A method to simulate beam properties observed at the beamline sample-point in the presence of motion of optical components has been developed at Diamond Light Source. A series of stationary ray-tracing simulations are used to model the impact on the beam stability caused by dynamic motion of optical elements. Ray-tracing simulations using SHADOW3 in OASYS, completed over multiple iterations and stitched together, permit the modelling of a pseudo-dynamic beamline. As beamline detectors operating at higher frequencies become more common, beam stability is crucial. Synchrotron ring upgrades to low-emittance lattices require increased stability of beamlines in order to conserve beam brightness. By simulating the change in beam size and position, an estimate of the impact the motion of various components have on stability is possible. The results presented in this paper focus on modelling the physical vibration of optical elements. Multiple beam parameters can be analysed in succession without manual input. The simulation code is described and the initial results obtained are presented. This method can be applied during beamline design and operation for the identification of optical elements that may introduce large errors in the beam properties at the sample-point.

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

Cited by 5 publications

References 3 publications

Beam and sample movement compensation for robust spectro-microscopy measurements on a hard X-ray nanoprobe

Beam and sample movement compensation for robust spectro-microscopy measurements on a hard X-ray nanoprobe

Current advances in synchrotron radiation instrumentation for MX experiments

Modelling the effects of optical vibrations on photon beam parameters using ray-tracing software

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