# FS-FLASH

 2019-07-0916:59 [PUBDB-2019-02680] Journal Article Wurth, W. 10 years of pioneering X-ray science at the Free-Electron Laser FLASH at DESY Physics reports 808, 1 - 74 (2019) [10.1016/j.physrep.2019.02.002]   Free-electron lasers produce extremely brief, coherent, and bright laser-like photon pulses that allow to image matter at atomic resolution and at timescales faster than the characteristic atomic motions. In pulses of about 50 femtoseconds duration they provide as many photons as one gets in 1 s from modern storage ring synchrotron radiation facilities [...] OpenAccess: PDF PDF (PDFA); 2019-07-0916:52 [PUBDB-2019-02679] Journal Article et al Normalized single-shot X-ray absorption spectroscopy at a free-electron laser Optics letters 44(9), 2157 - 2160 (2019) [10.1364/OL.44.002157]   A setup for dispersive X-ray absorption spectroscopy (XAS), employing a new reference scheme, has been implemented and tested at the soft X-ray free-electron laser (FEL) FLASH in Hamburg. A transmission grating was used to split the FEL beam into two copies (signal and reference). [...] OpenAccess: PDF PDF (PDFA); 2019-07-0916:47 [PUBDB-2019-02678] Journal Article et al Wavefront-propagation simulations supporting the design of a time-delay compensating monochromator beamline at FLASH2 Journal of synchrotron radiation 26(3), 899 - 905 (2019) [10.1107/S160057751900345X]   Wavefront-propagation simulations have been performed to complete the design of a monochromator beamline for FLASH2, the variable-gap undulator line at the soft X-ray free-electron laser in Hamburg (FLASH). Prior to propagation through the beamline optical elements, the parameters of the photon source were generated using the GENESIS code which includes the free-electron laser experimental data. [...] OpenAccess: PDF PDF (PDFA); Restricted: PDF PDF (PDFA); 2019-05-0809:15 [PUBDB-2019-02178] Journal Article et al Photon diagnostics at the FLASH THz beamline Journal of synchrotron radiation 26(3), 700 - 707 (2019) [10.1107/S1600577519003412]   The THz beamline at FLASH, DESY, provides both tunable (1–300 THz) narrow-bandwidth (∼10%) and broad-bandwidth intense (up to 150 uJ) THz pulses delivered in 1 MHz bursts and naturally synchronized with free-electron laser X-ray pulses. Combination of these pulses, along with the auxiliary NIR and VIS ultrashort lasers, supports a plethora of dynamic investigations in physics, material science and biology. [...] OpenAccess: PDF PDF (PDFA); 2019-01-0912:52 [PUBDB-2019-00176] Journal Article et al Ultrafast Self-Induced X-Ray Transparency and Loss of Magnetic Diffraction Physical review letters 121(13), 137403 (2018) [10.1103/PhysRevLett.121.137403]   Using ultrafast $≃2.5 fs$ and $≃25 fs$ self-amplified spontaneous emission pulses of increasing intensity and a novel experimental scheme, we report the concurrent increase of stimulated emission in the forward direction and loss of out-of-beam diffraction contrast for a $Co/Pd$ multilayer sample. The experimental results are quantitatively accounted for by a statistical description of the pulses in conjunction with the optical Bloch equations [...] OpenAccess: PDF PDF (PDFA); 2019-01-0911:12 [PUBDB-2019-00171] Journal Article et al Extreme ultraviolet probing of nonequilibrium dynamics in high energy density germanium Physical review / B 97(17), 174107 (2018) [10.1103/PhysRevB.97.174107]   Intense femtosecond infrared laser pulses induce a nonequilibrium between thousands of Kelvin hot valence electrons and room-temperature ions in a germanium sample foil. The evolution of this exotic state of matter is monitored with time-resolved extreme ultraviolet absorption spectroscopy across the Ge $M_{2,3}$ edge ($≃30 eV$) using the FERMI free-electron laser [...] OpenAccess: PDF PDF (PDFA); 2019-01-0809:02 [PUBDB-2019-00078] Journal Article et al Atom-specific activation in CO oxidation The journal of chemical physics 149(23), 234707 (2018) [10.1063/1.5044579]   We report on atom-specific activation of CO oxidation on Ru(0001) via resonant X-ray excitation. We show that resonant 1s core-level excitation of atomically adsorbed oxygen in the co-adsorbed phase of CO and oxygen directly drives CO oxidation. [...] Published on 2018-12-21. Available in OpenAccess from 2019-12-21.: PDF PDF (PDFA); 2018-12-2214:53 [PUBDB-2018-05889] Journal Article et al Disentangling Transient Charge Density and Metal–Ligand Covalency in Photoexcited Ferricyanide with Femtosecond Resonant Inelastic Soft X-ray Scattering The journal of physical chemistry letters 9(12), 3538 - 3543 (2018) [10.1021/acs.jpclett.8b01429]   Soft X-ray spectroscopies are ideal probes of the local valence electronic structure of photocatalytically active metal sites. Here, we apply the selectivity of time-resolved resonant inelastic X-ray scattering at the iron L-edge to the transient charge distribution of an optically excited charge-transfer state in aqueous ferricyanide. [...] OpenAccess: PDF PDF (PDFA); External link: Fulltext 2018-11-2816:43 [PUBDB-2018-04938] Poster et al Possible Upgrades of FLASH - A View from the Accelerator-Perspective 9th International Particle Accelerator Conference, IPAC'18, VancouverVancouver, Canada, 29 Apr 2018 - 4 May 2018   Recently FLASH (Free electron LASer in Hamburg) at DESY has been granted funding for a refurbishment project covering among others the replacement of two old SRF modules, an upgrade of the injector lasers and an upgrade of parts of the electron beam diagnostics.In addition we are proposing several possible upgrades and new features for the injector and the drive linac as well as in the undulator beamlines.Here we present options which are in our opinion technically feasible and at the same time operationally manageable.. OpenAccess: PDF PDF (PDFA); 2018-11-2816:38 [PUBDB-2018-04937] Contribution to a conference proceedings et al Possible Upgrades of FLASH - A View from the Accelerator-Perspective 9th International Particle Accelerator Conference, IPAC'18, VancouverVancouver, Canada, 29 Apr 2018 - 4 May 2018 Geneva, Switzerland : JACoW 4 pp. (2018) [10.3204/PUBDB-2018-04937]   Recently FLASH (Free electron LASer in Hamburg) at DESY has been granted funding for a refurbishment project covering among others the replacement of two old SRF modules, an upgrade of the injector lasers and an upgrade of parts of the electron beam diagnostics.In addition we are proposing several possible upgrades and new features for the injector and the drive linac as well as in the undulator beamlines.Here we present options which are in our opinion technically feasible and at the same time operationally manageable.. OpenAccess: PDF PDF (PDFA); External link: Fulltext