Refined betatron tune measurements by mixing beam position data

A sensitive current-measuring system is required to construct a highly sensitive X-ray beam-position monitor (XBPM). A current–voltage converter (I/V) which can measure currents between 0.1 nA and 10 mA was designed, and the signal processing system of the XBPM was constucted using this I/V. This system was used in beamline commissioning. Beam-position data standard deviations of σ ≃ 3 µm for the bending-magnet beamline, and σ x ≃ 3 µm and σ y ≃ 1 µm for the insertion-device beamline were obtained during the beamline commissioning.

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Operation of X-ray gas monitors at the European XFEL

Journal of Synchrotron Radiation ◽

10.1107/s1600577519003795 ◽

2019 ◽

Vol 26 (4) ◽

pp. 1045-1051 ◽

Cited By ~ 9

Author(s):

Theophilos Maltezopoulos ◽

Florian Dietrich ◽

Wolfgang Freund ◽

Ulf Fini Jastrow ◽

Andreas Koch ◽

...

Keyword(s):

Pulse Energy ◽

Absolute Measurement ◽

Single Shot ◽

Main Principle ◽

Beam Position ◽

X Ray ◽

Non Invasive ◽

Position Data ◽

Monitor Data ◽

Position Monitoring

X-ray gas monitors (XGMs) are operated at the European XFEL for non-invasive single-shot pulse energy measurements and average beam position monitoring. They are used for tuning and maintaining the self-amplified spontaneous emission (SASE) operation and for sorting single-shot experimental data according to the pulse-resolved energy monitor data. The XGMs were developed at DESY based on the specific requirements for the European XFEL. In total, six XGM units are continuously in operation. Here, the main principle and experimental setup of an XGM are summarized, and the locations of the six XGMs at the facility are shown. Pulse energy measurements at 0.134 nm wavelength are presented, exceeding 1 mJ obtained with an absolute measurement uncertainty of 7–10%; correlations between different XGMs are shown, from which a SASE1 beamline transmission of 97% is deduced. Additionally, simultaneous position measurements close to the undulator and at the end of the tunnel are shown, along with the correlation of beam position data simultaneously acquired by an XGM and an imager.

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Analysis and control of the photon beam position at PLS-II

Journal of Synchrotron Radiation ◽

10.1107/s1600577516001338 ◽

2016 ◽

Vol 23 (2) ◽

pp. 448-454

Author(s):

J. Ko ◽

I.-Y. Kim ◽

C. Kim ◽

D.-T. Kim ◽

J.-Y. Huang ◽

...

Keyword(s):

Decomposition Analysis ◽

Feedback System ◽

Critical Issue ◽

Photon Beam ◽

Real Photon ◽

Light Sources ◽

Beam Position Monitor ◽

Singular Value Decomposition Analysis ◽

Beam Position ◽

Position Data

At third-generation light sources, the photon beam position stability is a critical issue for user experiments. In general, photon beam position monitors are developed to detect the real photon beam position, and the position is controlled by a feedback system in order to maintain the reference photon beam position. At Pohang Light Source II, a photon beam position stability of less than 1 µm r.m.s. was achieved for a user service period in the beamline, where the photon beam position monitor is installed. Nevertheless, a detailed analysis of the photon beam position data was necessary in order to ensure the performance of the photon beam position monitor, since it can suffer from various unknown types of noise, such as background contamination due to upstream or downstream dipole radiation, and undulator gap dependence. This paper reports the results of a start-to-end study of the photon beam position stability and a singular value decomposition analysis to confirm the reliability of the photon beam position data.

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Quantitative x-ray microanalysis and thickness determination using ζ factor

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100165367 ◽

1996 ◽

Vol 54 ◽

pp. 580-581

Author(s):

M. Watanabe ◽

Z. Horita ◽

M. Nemoto

Keyword(s):

Diffusion Couple ◽

Extrapolation Method ◽

Thin Specimen ◽

Beam Position ◽

X Ray ◽

Thickness Determination ◽

Experimental Limitation ◽

X Ray Absorption

X-ray absorption in quantitative x-ray microanalysis of thin specimens may be corrected without knowledge of thickness when the extrapolation method or the differential x-ray absorption (DXA) method is used. However, there is an experimental limitation involved in each method. In this study, a method is proposed to overcome such a limitation. The method is developed by introducing the ζ factor and by combining the extrapolation method and DXA method. The method using the ζ factor, which is called the ζ-DXA method in this study, is applied to diffusion-couple experiments in the Ni-Al system.For a thin specimen where incident electrons are fully transparent, the characteristic x-ray intensity generated from a beam position, I, may be represented as I = (NρW/A)Qωaist.

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