Spectrometer for shot-to-shot photon energy characterization in the multi-bunch mode of the free electron laser at Hamburg

Palutke, Steffen; Gerken, N.; Mertens, K.; Klumpp, S.; Mozzanica, A.; Schmitt, B.; Wunderer, C.; Graafsma, H.; Meiwes‐Broer, Karl‐Heinz; Würth, W.; Martins, M.

doi:10.1063/1.4936293

Cited by 7 publications

(2 citation statements)

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“…This also allows for spectral analysis of the FEL beam via inspection of the grating's different diffraction orders [9,10]. In the case of soft x-ray monochromator beamlines, the monochromator's diffraction orders that are not transported to the experiment can be used in a similar fashion [11]. Due to space constraints, however, none of the mentioned concepts are typically located immediately upstream of the sample.…”

Section: Introductionmentioning

confidence: 99%

Curved gratings as an integrated photon fluence monitor in x-ray transmission scattering experiments

et al. 2016

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A concept to obtain a measure of the photon flux accepted by a solid sample in single-shot transmission experiments with extreme ultraviolet (XUV) or soft x-ray radiation is demonstrated. Shallow, continuously distorted gratings are used to diffract a constant fraction of the incident photons onto an extended area of a CCD detector. The signal can be tailored to fit the dynamic range of the detector, i.e. matching the scattered intensity of the studied structure of interest. Furthermore, composite grating designs that also allow for the measurement of the spatial photon distribution on the sample are demonstrated. The gratings are directly fabricated by focused ion-beam (FIB) lithography into a Si₃N₄ membrane that supports the actual sample layer. This allows for rapid fabrication of hundreds of samples, making the concept suitable for systematic studies in destructive single-shot measurements at free-electron laser (FEL) sources. We demonstrate relative photon flux measurements in magnetic scattering experiments with synchrotron and FEL radiation at 59.6 eV photon energy.

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Section: Introductionmentioning

confidence: 99%

Curved gratings as an integrated photon fluence monitor in x-ray transmission scattering experiments

et al. 2016

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“…Such a setup in combination with new-generation ICCD cameras with high frame rates or fast line detectors, such as the GOTTHARD detector (Mozzanica et al, 2012), poses a promising concept for a grating-based online spectrometer capable of single-shot resolved measurements with up to MHz repetition rate (Palutke et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Non-invasive online wavelength measurements at FLASH2 and present benchmark

et al. 2018

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Edited by M. Zangrando, IOM-CNR and Elettra-Sincrotrone, ItalyKeywords: free-electron laser; soft X-ray; wavelength; photoionization; rare gases. At FLASH2, the free-electron laser radiation wavelength is routinely measured by an online spectrometer based on photoionization of gas targets. Photoelectrons are detected with time-of-flight spectrometers and the wavelength is determined by means of well known binding energies of the target species. The wavelength measurement is non-invasive and transparent with respect to running user experiments due to the low gas pressure applied. Sophisticated controls for setting the OPIS operation parameters have been created and integrated into the distributed object-oriented control system at FLASH2. Raw and processed data can be stored on request in the FLASH data acquisition system for later correlation with data from user experiments or re-analysis. In this paper, the commissioning of the instrument at FLASH2 and the challenges of space charge effects on wavelength determination are reported. Furthermore, strategies for fast data reduction and online data processing are presented.

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