Field measurement facility for the PAL-XFEL undulator

Park, K. H.; Jung, Y. G.; Kim, D. E.; Lee, H. G.; Suh, Hyung; Han, Hyunsook; Lee, S. B.; Lee, M. S.; Lee, B. H.; Sung, ChiWon; Kim, S. N.; Ko, In Soo

doi:10.3938/jkps.66.317

Cited by 5 publications

(3 citation statements)

References 2 publications

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“…L C is a fixed variable and PI u is an independent variable for the different K, while PI ps can be a practical control parameter easily controlled by changing the gap of the phase-shifter. The magnetic field measurement for the undulator and the phase-shifter was carried out at the field measurement lab, where the ambient temperature and earth magnetic field were controlled the same as that at the installation site in the undulator hall of PAL-XFEL [10,21]. Particularly, the ambient temperature variations should be better than ±0.1 • C to minimize the field variation of the magnetic block [21,22].…”

Section: Phase-shifter To Compensate For the Slippagementioning

confidence: 99%

“…The magnetic field measurement for the undulator and the phase-shifter was carried out at the field measurement lab, where the ambient temperature and earth magnetic field were controlled the same as that at the installation site in the undulator hall of PAL-XFEL [10,21]. Particularly, the ambient temperature variations should be better than ±0.1 • C to minimize the field variation of the magnetic block [21,22]. The phase slippage along the free space with a distance of L D between undulator segments is [23]…”

Section: Phase-shifter To Compensate For the Slippagementioning

confidence: 99%

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Control Scheme of Phase-Shifter for Photon Energy Scan

et al. 2022

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Variable gap undulator widely used in X-ray free-electron laser (XFEL) enables the photon energy scan by changing its gap. A phase-shifter should be incorporated to compensate for the phase mismatch between the electron bunches and X-ray pulses arising while those traverse the drift space between undulator segments. The uncertainties in both the undulator parameter and the drift space distance introduce an error in calculating the optimum gap distance of the phase-shifter for the different undulator K. The phase-shifter gap needs to be set where the error is within the tolerable range. The control scheme we propose can maintain full FEL intensity over the scanned photon energies.

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Section: Phase-shifter To Compensate For the Slippagementioning

confidence: 99%

Section: Phase-shifter To Compensate For the Slippagementioning

confidence: 99%

Control Scheme of Phase-Shifter for Photon Energy Scan

et al. 2022

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“…This undulator is to be installed into the beamline in February 2021. A measurement system consisting of 3-D Hall probe with three Bell 1-D Hall sensors and a single stretched wire [7] were used for the measurements. The measurements were carried out before and after pole tuning, by changing the vertical offset to the magnetic field center.…”

Section: Pal-xfel Undulator Off-axis Field Errormentioning

confidence: 99%

Off-axis parameters of PAL-XFEL planar undulator

Lee

Han

2021

J. Inst.

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The electron beam path in a planar undulator is usually chosen at the undulator magnetic center in both the vertical and horizontal directions. In the case of the vertical-gap undulators of x-ray free-electron lasers, best efforts are paid to align the vertical magnetic center to the reference electron beam path. The twenty undulator segments are aligned vertically within 50 μm to obtain the target 𝐾-values of the undulator segments in the PAL-XFEL hard X-ray beamline. Besides 𝐾value, undulator phase error and beam trajectory deflection are also concerned when the undulator is misaligned to the beam path. In some cases, an off-set in the vertical direction is applied intentionally when a transverse field gradient is required. In this report, we present the systematic measurements of the phase error and trajectory deflection at vertical off-axes of a PAL-XFEL hard X-ray undulator.

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Measurement and Optimization of Undulator for a THz-Band FEL Oscillator

Liu

Deng

et al. 2018

2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT)

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Field measurement facility for the PAL-XFEL undulator

Cited by 5 publications

References 2 publications

Control Scheme of Phase-Shifter for Photon Energy Scan

Control Scheme of Phase-Shifter for Photon Energy Scan

Off-axis parameters of PAL-XFEL planar undulator

Measurement and Optimization of Undulator for a THz-Band FEL Oscillator

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