Magnetic Measurement Techniques for the Large-Scale Production of Undulator Segments for the European XFEL

Li, Yuhui; Abeghyan, Suren; Berndgen, Karl-Heinz; Baha-Shanjani, M.; Deron, G.; Englisch, Uwe; Karabekyan, S.; Ketenoglu, Bora; Knoll, M.; Wolff-Fabris, F.; Viehweger, Marc; Yakopov, Mikhail; Pflueger, J.

doi:10.1080/08940886.2015.1037679

Cited by 10 publications

(8 citation statements)

References 9 publications

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“…Undulators and phase shifters are well characterized before installation: Undulators were accurately tuned for small trajectory and phase errors in the operational gap range [8,9]. After tuning the characterization for each segment includes high resolution field maps as a function of gap in 0.5 mm steps.…”

Section: Introductionmentioning

confidence: 99%

Phase matching strategy for the undulator system in the European X-ray Free Electron Laser

Pflueger

2017

Phys. Rev. Accel. Beams

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The undulator system in the European X-ray Free Electron Laser is mainly comprised of 5-m long undulator segments and 1.1 m long intersections in between. The longitudinal component of the electrons' velocity is reduced when traveling inside an undulator due to the wiggle motion. Therefore the optical phase is detuned. The detune effect is also from the undulator fringe field where electron longitudinal speed also deviates from the oscillation condition. The total detune effect is compensated by a magnetic device called phase shifter, which is correspondingly set for a specific undulator gap. In this paper we investigate the homogeneity of the fringe field from different undulators. Different phase matching criteria are studied. The field fitting technique for the phase matching in high accuracy is demonstrated in detail. The impact by air coil is also studied. Eventually the matching test by spontaneous radiation simulation is made. A test method for high sensitivity to matching error is proposed.

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Section: Introductionmentioning

confidence: 99%

Phase matching strategy for the undulator system in the European X-ray Free Electron Laser

Pflueger

2017

Phys. Rev. Accel. Beams

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“…Gap-dependent shims might be used to bring back the trajectory into the specified range. This has been observed on a few of the 91 5 m long undulator segments for the European XFEL, and shims were successfully applied [18]. (iii) The precision shimming methods described in this paper can in principle be extended to limit the gradient over a large horizontal good field range for low first field integral errors.…”

Section: Discussionmentioning

confidence: 94%

Tuning method for phase shifters with very low first field integral errors for the European X-ray Free Electron Laser

Pflueger

2015

Phys. Rev. ST Accel. Beams

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For the long gap tunable undulator systems of the European XFEL, 91 phase shifters are needed. They need to fulfil stringent and demanding field integral tolerances if their strengths, i.e., their magnetic gaps, are changed. In order to avoid additional correctors, their first field integral errors must not exceed AE0.004 Tmm for self-amplified spontaneous emission operation at 1 Å. For longer wavelengths there are slightly relaxed requirements. In addition, a good field range of AE0.5 mm is required. Phase shifters are manufactured by using state of the art techniques such as measurement and sorting of magnets, measurement and sorting of subassemblies, etc. In spite of these efforts, inhomogeneities of the permanent magnet material as well as mechanic manufacturing errors, which cannot be avoided and lead to violations of the demanding first field integral specifications. Therefore, a fast and robust shimming technique was developed for the serial production of these devices. It is based on measured signatures of shims with different geometries and uses symmetry properties of shims placed on different positions and poles with different polarity. In this paper, the specifications for the phase shifters in the European XFEL are derived first. Then the method is described in detail and results are presented, which demonstrate that all requirements can be fulfilled.

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“…In general, thickness of the beam pipe determines the minimum value of gap. For instance, considering the case for European XFEL, thickness of the beam pipe is 10 mm, resulting in a minimum gap value of g min =10 mm as indicated in Table 1 (Li et al, 2015). Furthermore, one of the most important parameter of an undulator is the K parameter (Equation 2), which is directly derivated from peak field.…”

Section: Peak Field and K Parameter Concepts With Real Comperative Rementioning

confidence: 99%

Bi̇r X-Işini Salindiricisinin İşleti̇me Hazir Hale Geti̇ri̇lmesi̇: Üreti̇mi̇n Ardindan Tünele Kurulana Kadar İzlenen Prosedürler

Ketenoglu¹

2018

Uludağ University Journal of the Faculty of Engineering

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In this study, sequence of events for an X-ray undulator generating Free Electron Laser (FEL) pulses down to hard X-rays of the electromagnetic spectrum, are discussed in detail. As soon as an undulator arrives to a Magnetic Measurements Hutch (MMH), a series of treatment steps start to make it ready for commissioning, beginning with a high-precision magnetic alignment procedure. Once Hall probe and undulator are accurately aligned to each other, then gap-dependent measurements begin to create tuning lists. After completion of mechanical tuning of poles, MMH 3D-coordinates have to be transformed to the coordinates of tunnel, where many undulator cells will be sequenced one after another along a linear path. Here, all optical, mechanical and magnetic procedures that an X-ray undulator experiences before commissioning, are thoroughly explained. Furthermore, effects of different types of Hall probes on magnetic measurements, are discussed as well. Finally, whole algorithm subsequent to fabrication until tunnel installation (i.e. optical and magnetic alignment, pole tuning, phase jitter therapy etc.), are summarized by means of the results of magnetic measurements taken in three identical MMHs of European XFEL facility.

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Magnetic Measurement Techniques for the Large-Scale Production of Undulator Segments for the European XFEL

Cited by 10 publications

References 9 publications

Phase matching strategy for the undulator system in the European X-ray Free Electron Laser

Phase matching strategy for the undulator system in the European X-ray Free Electron Laser

Tuning method for phase shifters with very low first field integral errors for the European X-ray Free Electron Laser

Bi̇r X-Işini Salindiricisinin İşleti̇me Hazir Hale Geti̇ri̇lmesi̇: Üreti̇mi̇n Ardindan Tünele Kurulana Kadar İzlenen Prosedürler

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