# FS-FLASH-O

 2018-09-3017:41 [PUBDB-2018-03676] Journal Article et al Phase transition lowering in dynamically compressed silicon Nature physics xxx(xxx), xxx (2018) [10.1038/s41567-018-0290-x]   Silicon, being one of the most abundant elements in nature, attracts wide-ranging scientific and technological interest. Specifically, in its elemental form, crystals of remarkable purity can be produced. [...] Restricted: PDF PDF (PDFA); 2018-09-2710:43 [PUBDB-2018-03641] Journal Article et al Probing the non-equilibrium transient state in magnetite by a jitter-free two-color X-ray pump and X-ray probe experiment Structural dynamics 5(5), 054501 (2018) [10.1063/1.5042847]   We present a general experimental concept for jitter-free pump and probe experiments at free electron lasers. By generating pump and probe pulse from one and the same X-ray pulse using an optical split-and-delay unit, we obtain a temporal resolution that is limited only by the X-ray pulse lengths. [...] OpenAccess: PDF PDF (PDFA); 2018-09-2710:36 [PUBDB-2018-03640] Journal Article et al Signatures of autoionization in the angular electron distribution in two-photon double ionization of Ar Physical review / A 98(3), 033408 (2018) [10.1103/PhysRevA.98.033408]   A kinematically complete experiment on two-photon double ionization of Ar by free-electron laser radiation with a photon energy of 27.93 eV was performed. The electron energy spectra show that double ionization is dominated by the sequential process. [...] OpenAccess: PDF PDF (PDFA); 2018-08-3010:18 [PUBDB-2018-03255] Journal Article et al XUV double-pulses with femtosecond to 650 ps separation from a multilayer-mirror-based split-and-delay unit at FLASH Journal of synchrotron radiation 25(5), 1517 - 1528 (2018) [10.1107/S1600577518006094]   Extreme ultraviolet (XUV) and X-ray free-electron lasers enable new scientific opportunities. Their ultra-intense coherent femtosecond pulses give unprecedented access to the structure of undepositable nanoscale objects and to transient states of highly excited matter [...] OpenAccess: PDF PDF (PDFA); 2018-08-2014:27 [PUBDB-2018-03069] Journal Article et al CAMP@FLASH: an end-station for imaging, electron- and ion-spectroscopy, and pump–probe experiments at the FLASH free-electron laser Journal of synchrotron radiation 25(5), 1529 - 1540 (2018) [10.1107/S1600577518008585]   The non-monochromatic beamline BL1 at the FLASH free-electron laser facility at DESY was upgraded with new transport and focusing optics, and a new permanent end-station, CAMP, was installed. This multi-purpose instrument is optimized for electron- and ion-spectroscopy, imaging and pump–probe experiments at free-electron lasers [...] OpenAccess: PDF PDF (PDFA); 2018-06-0613:58 [PUBDB-2018-02209] Journal Article et al Rapid Sample Delivery for Megahertz Serial Crystallography at X-ray FELs IUCrJ 5(5), 574 - 584 (2018) [10.1107/S2052252518008369]   Liquid microjets are a common means of delivering protein crystals to the focus of X-ray free-electron lasers (FELs) for serial femtosecond crystallography measurements. The high X-ray intensity in the focus initiates an explosion of the microjet and sample. [...] OpenAccess: PDF PDF (PDFA); 2018-05-1415:17 [PUBDB-2018-01956] Journal Article et al Time-resolved inner-shell photoelectron spectroscopy: From a bound molecule to an isolated atom Physical review / A 97(4), 043429 (2018) [10.1103/PhysRevA.97.043429]   Due to its element and site specificity, inner-shell photoelectron spectroscopy is a widely used technique to probe the chemical structure of matter. Here, we show that time-resolved inner-shell photoelectron spectroscopy can be employed to observe ultrafast chemical reactions and the electronic response to the nuclear motion with high sensitivity. [...] Fulltext: PNG; OpenAccess: PDF PDF (PDFA); 2018-05-1415:05 [PUBDB-2018-01953] Journal Article et al Time-resolved ion imaging at free-electron lasers using TimepixCam Journal of synchrotron radiation 25(2), 336 - 345 (2018) [10.1107/S1600577517018306]   The application of a novel fast optical-imaging camera, TimepixCam, to molecular photoionization experiments using the velocity-map imaging technique at a free-electron laser is described. TimepixCam is a 256 × 256 pixel CMOS camera that is able to detect and time-stamp ion hits with 20 ns timing resolution, thus making it possible to record ion momentum images for all fragment ions simultaneously and avoiding the need to gate the detector on a single fragment. [...] Restricted: 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. [...] Fulltext: PNG; OpenAccess: PDF PDF (PDFA); 2018-01-0316:49 [PUBDB-2018-00094] Journal Article/Contribution to a conference proceedings/Contribution to a book Yurkov, M. Frequency Doubler and Two-Color Mode of Operation at Free Electron Laser FLASH2 Proc. SPIE, 2017. - ISBN - doi:10.1117/12.2265584Advances in X-ray Free-Electron Lasers Instrumentation IV, PraguePrague, Czech Republic, 24 Apr 2017 - 27 Apr 2017 Proceedings of SPIE 10237, 1023710 (2017) [10.1117/12.2265584] special issue: "Advances in X-ray Free-Electron Lasers Instrumentation IV"   We report on the results of the first operation of a frequency doubler at FLASH2. The scheme uses the feature of the variable gap of the undulator. [...] OpenAccess: 1023710 - PDF PDF (PDFA); 10237-35_Yurkov_Doubler-SPIE - PDF PDF (PDFA);