FEL research and development at the SLAC sub-picosecond photon source, SPPS

Bentson, L.; Bolton, Paul R.; Bong, E.; Emma, P.; Galayda, J.; Hastings, J. B.; Krejcik, P.; Rago, C.E.; Rifkin, J.; Spencer, C.M.

doi:10.1016/s0168-9002(03)00875-1

Cited by 30 publications

(12 citation statements)

References 2 publications

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“…4. The detector was designed to be tested at the SPPS in Stanford, 34 which was, until its shutdown in 2006, a worldwide unique femtosecond x-ray source with a rather moderate photon number per pulse, on the order of 10 6 at the photon energy of 9.4 TABLE I. Total photoionization cross section and mean charge q created per absorbed photon as a function of photon energy ប for the rare gases helium to xenon.…”

Section: Gmds For Hard X-ray Felsmentioning

confidence: 99%

Gas detectors for x-ray lasers

Tiedtke¹,

Feldhaus²,

Hahn³

et al. 2008

Journal of Applied Physics

165

128

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We have developed different types of photodetectors that are based on the photoionization of a gas at a low target density. The almost transparent devices were optimized and tested for online photon diagnostics at current and future x-ray free-electron laser facilities on a shot-to-shot basis with a temporal resolution of better than 100 ns. Characterization and calibration measurements were performed in the laboratory of the Physikalisch-Technische Bundesanstalt at the electron storage ring BESSY II in Berlin. As a result, measurement uncertainties of better than 10% for the photon-pulse energy and below 20 m for the photon-beam position were achieved at the Free-electron LASer in Hamburg ͑FLASH͒. An upgrade for the detection of hard x-rays was tested at the Sub-Picosecond Photon Source in Stanford.

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Section: Gmds For Hard X-ray Felsmentioning

confidence: 99%

Gas detectors for x-ray lasers

Tiedtke¹,

Feldhaus²,

Hahn³

et al. 2008

Journal of Applied Physics

165

128

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“…We describe here diffuse x-ray scattering measurements in which the structural dynamics of the liquid-state and the subsequent ablation process are directly measured with subpicosecond resolution. Measurements were performed at the Stanford linear accelerator center using the sub-picosecond pulse source, a precursor to future hard x-ray free electron lasers [13] and a spontaneous source of 9 keV x-rays with a pulse duration of 80 fs FWHM [14]. The setup is similar to the schematic shown in reference [15].…”

mentioning

confidence: 99%

X-Ray Diffuse Scattering Measurements of Nucleation Dynamics at Femtosecond Resolution

et al. 2008

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Femtosecond time-resolved small and wide angle x-ray diffuse scattering techniques are applied to investigate the ultrafast nucleation processes that occur during the ablation process in semiconducting materials. Following intense optical excitation, a transient liquid state of high compressibility characterized by large-amplitude density fluctuations is observed and the buildup of these fluctuations is measured in real time. Small-angle scattering measurements reveal snapshots of the spontaneous nucleation of nanoscale voids within a metastable liquid and support theoretical predictions of the ablation process. DOI: 10.1103/PhysRevLett.100.135502 PACS numbers: 79.20.Ds, 61.05.cp, 61.20.Lc, 64.60.ÿi The liquid state of matter can be both supercooled below its freezing point and superheated above its boiling point. Although these are nonequilibrium states, their lifetime is longer than typical laboratory observation times and they are thus classified as metastable, stuck in a local minimum of the free energy. Despite their apparent stability, these systems exhibit localized fluctuations, corresponding to nuclei of the lower energy phase which rapidly form and dissolve, a process for which there exists a critical size for stable growth of the equilibrium phase, typically of nanoscale dimensions [1-3] (depending on the degree of superheating). When the transition does occur, it occurs rapidly, as is familiar to anyone who has observed the catastrophic boiling that suddenly occurs in superheated liquid water [4]. The development of ultrafast, atomic-scale sensitive techniques enables one to capture these transient, intermediate states, which under current laboratory methods, may spontaneously transform to lower energy stable states on inaccessible time scales. Techniques like time-resolved x-ray or electron scattering record these intermediate states in the form of a diffuse scattering pattern whose shape reflects the local atomic-scale structure that characterizes the transforming material. As a result of the orientational isotropy in the system and the short correlation lengths, these are typically broad diffraction rings, in contrast to the well-defined diffracted beams one obtains from a crystalline system. The radially averaged diffracted intensity as a function of scattering angle (normalized by atomic scattering factors) is a direct measure of the liquid structure factor S Q , where Q 4 sin = is the momentum transfer, 2 is the scattering angle, and is the wavelength, which directly encodes the short-range correlations in disordered materials.Recent experiments probing atomic-scale dynamics in disordered systems using electron diffraction techniques have focused on gas-phase photochemical reactions [5],

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“…Since the very first ultrafast structural experiments at SPPS [43,103,104], the brightness of XFELs has increased by about one million fold, allowing for the study of more complex systems and photoinduced phenomena such as protein dynamics in crystalline [105][106][107][108][109][110][111][112] and liquid phases, [113] bond formation in the [Au(CN) 2 -] 3 trimer in solution, [114,115] lattice dynamics in individual gold nanoparticles, [116] ultrafast melting of charge and orbital order in PCMO, [117] non-linear lattice dynamics [118] and CWD order in YBCO, [119] visualization of breathing modes in nanocrystals at extreme photoexcitation conditions, [120] photoinduced insulator-to-metal (IM) transitions, [121] warm dense matter physics, [122] and ultrafast crystallization [123] and melting [124] in shock-compressed crystals. Figure 9a-d shows time-resolved X-ray diffraction results obtained by Barends et al [107] at LCLS in the investigation of the ultrafast structural dynamics that follows CO photodissociation in Myoglobin-CO (MbCO).…”

Section: Time-resolved Fs-x-ray Crystallography and Scatteringmentioning

confidence: 99%

“…Thus, the application of intense fs-mid-IR lasers may bring the effective brightness of table-top fs-hard X-ray diffractometers to the level of~10 5 -10 6 photons/pulse (at sample position). This is about one order of magnitude below the flux achieved at the Sub-Picosecond Photon Source (SPPS) [43]. SPPS was a test facility that operated at the Stanford Linear Accelerator Center (SLAC) before the Linac Coherent Light Source (LCLS) became available in 2009 (see section below).…”

Section: Introduction To Fourth-generation Fs-hard X-ray Sources: X-rmentioning

confidence: 99%

Recent Advances in Ultrafast Structural Techniques

Sciaini

2019

Applied Sciences

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A review that summarizes the most recent technological developments in the field of ultrafast structural dynamics with focus on the use of ultrashort X-ray and electron pulses follows. Atomistic views of chemical processes and phase transformations have long been the exclusive domain of computer simulators. The advent of femtosecond (fs) hard X-ray and fs-electron diffraction techniques made it possible to bring such a level of scrutiny to the experimental area. The following review article provides a summary of the main ultrafast techniques that enabled the generation of atomically resolved movies utilizing ultrashort X-ray and electron pulses. Recent advances are discussed with emphasis on synchrotron-based methods, tabletop fs-X-ray plasma sources, ultrabright fs-electron diffractometers, and timing techniques developed to further improve the temporal resolution and fully exploit the use of intense and ultrashort X-ray free electron laser (XFEL) pulses.

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FEL research and development at the SLAC sub-picosecond photon source, SPPS

Cited by 30 publications

References 2 publications

Gas detectors for x-ray lasers

Gas detectors for x-ray lasers

X-Ray Diffuse Scattering Measurements of Nucleation Dynamics at Femtosecond Resolution

Recent Advances in Ultrafast Structural Techniques

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