# FS-FLASH-D

 2018-01-1715:59 [PUBDB-2018-00674] Journal Article et al Near-K -edge single, double, and triple photoionization of $C^{+}$ ions Physical review / A 97(1), 013409 (2018) [10.1103/PhysRevA.97.013409]   Single, double, and triple ionization of the $C^{+}$ ion by a single photon have been investigated in the energy range 286 to 326 eV around the K-shell single-ionization threshold at an unprecedented level of detail. At energy resolutions as low as 12 meV, corresponding to a resolving power of 24 000, natural linewidths of the most prominent resonances could be determined [...] OpenAccess: PDF PDF (PDFA); External link: Fulltext 2018-01-1113:18 [PUBDB-2018-00484] Journal Article et al Circular Dichroism in Multiphoton Ionization of Resonantly Excited $He^{+}$ Ions Physical review letters 118(1), 013002 (2017) [10.1103/PhysRevLett.118.013002]   Intense, circularly polarized extreme-ultraviolet and near-infrared (NIR) laser pulses are combined to double ionize atomic helium via the oriented intermediate He+(3p) resonance state. Applying angle-resolved electron spectroscopy, we find a large photon helicity dependence of the spectrum and the angular distribution of the electrons ejected from the resonance by NIR multiphoton absorption. [...] OpenAccess: PDF PDF (PDFA); 2018-01-0910:44 [PUBDB-2018-00272] Journal Article et al Ultrashort Free-Electron Laser X-ray Pulses Applied Sciences 7(9), 915 - (2017) [10.3390/app7090915]   For the investigation of processes happening on the time scale of the motion of bound electrons, well-controlled X-ray pulses with durations in the few-femtosecond and even sub-femtosecond range are a necessary prerequisite. Novel free-electron lasers sources provide these ultrashort, high-brightness X-ray pulses, but their unique aspects open up concomitant challenges for their characterization on a suitable time scale [...] OpenAccess: PDF PDF (PDFA); 2018-01-0815:32 [PUBDB-2018-00266] Journal Article et al Saturation of a Ce:$\mathrm{Y}_{3}\mathrm{Al}_{5}\mathrm{O}_{12}$ scintillator response to ultra-short pulses of extreme ultraviolet soft X-ray and X-ray laser radiation Optical materials express 7(3), 665 - 675 (2017) [10.1364/OME.7.000665]   Investigations of radioluminescence saturation in monocrystalline cerium doped yttrium aluminum garnet (Ce:YAG) exposed to intense extreme ultraviolet (XUV), soft X-ray and X-ray radiation delivered from three free-electron lasers are described in this article. The measurements were performed with wavelengths of 98, 25.6, 13.5 and 0.15 nm. [...] OpenAccess: PDF PDF (PDFA); 2018-01-0513:44 [PUBDB-2018-00199] Journal Article et al Photodissociation of Aligned $\mathrm{CH_3I}$ and $\mathrm{C_{6}H_{3}F_{2}I}$ Molecules Probed with Time-Resolved Coulomb Explosion Imaging by Site-Selective XUV Ionization Structural dynamics 5(1), 014301 - (2018) [10.1063/1.4998648]   We explore time-resolved Coulomb explosion induced by intense, extreme ultraviolet (XUV) femtosecond pulses from a free-electron laser as a method to image photo-induced molecular dynamics in two molecules, iodomethane and 2,6-difluoroiodobenzene. At an excitation wavelength of 267 nm, the dominant reaction pathway in both molecules is neutral dissociation via cleavage of the carbon–iodine bond. [...] OpenAccess: PDF PDF (PDFA); 2017-12-2214:02 [PUBDB-2017-14060] Journal Article et al Experimental study of EUV mirror radiation damage resistance under long-term free-electron laser exposures below the single-shot damage threshold Journal of synchrotron radiation 25(1), 77 - 84 (2018) [10.1107/S1600577517017362]   The durability of grazing- and normal-incidence optical coatings has been experimentally assessed under free-electron laser irradiation at various numbers of pulses up to 16 million shots and various fluence levels below 10% of the single-shot damage threshold. The experiment was performed at FLASH, the Free-electron LASer in Hamburg, using 13.5 nm extreme UV (EUV) radiation with 100 fs pulse duration. [...] OpenAccess: PDF PDF (PDFA); 2017-12-2213:55 [PUBDB-2017-14056] Journal Article et al Imaging the square of the correlated two-electron wave function of a hydrogen molecule Nature Communications 8(1), 2266 (2017) [10.1038/s41467-017-02437-9]   The toolbox for imaging molecules is well-equipped today. Some techniques visualize the geometrical structure, others the electron density or electron orbitals. [...] Restricted: PDF PDF (PDFA); 2017-12-1818:46 [PUBDB-2017-13675] Journal Article et al Non-invasive online wavelength measurements at FLASH2 and present benchmark Journal of synchrotron radiation 25(1), 3 - 15 (2018) [10.1107/S1600577517013893] special issue: "PhotonDiag2017 Workshop special issue"   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 [...] OpenAccess: PDF PDF (PDFA); 2017-11-1010:23 [PUBDB-2017-11856] Bachelor Thesis Schunck, J. Röntgenabsorptionsspektroskopie an chemisch und thermisch behandelten Kupfer-Beryllium Legierungen 59 pp. (2017) = Bachelorarbeit, University of Hamburg, 2017 Due to their high secondary electron yield, copper-beryllium alloys with a beryllium molefraction of approximately 14 % (Cu 0.86 Be 0.14 ) are commercially available materials fordynodes of charged particle detectors. By using multiple layers of dynodes, even singleparticles can be detected. [...] 2017-11-0910:46 [PUBDB-2017-11808] Journal Article et al Coulomb-explosion imaging of concurrent $\mathrm{CH_2BrI}$ photodissociation dynamics Physical review / A 96(4), 043415 (2017) [10.1103/PhysRevA.96.043415]   The dynamics following laser-induced molecular photodissociation of gas-phase CH$_{2}$BrI at 271.6 nm were investigated by time-resolved Coulomb-explosion imaging using intense near-IR femtosecond laser pulses. The observed delay-dependent photofragment momenta reveal that CH$_{2}$BrI undergoes C-I cleavage, depositing 65.6% of the available energy into internal product states, and that absorption of a second UV photon breaks the C-Br bond ofCH$_{2}$Br. [...] Fulltext: PDF PDF (PDFA); OpenAccess: PDF PDF (PDFA); External link: Fulltext