scholarly journals Direct imaging of ultrafast lattice dynamics

2019 ◽  
Vol 5 (3) ◽  
pp. eaau8044 ◽  
Author(s):  
S. Brennan Brown ◽  
A. E. Gleason ◽  
E. Galtier ◽  
A. Higginbotham ◽  
B. Arnold ◽  
...  
Keyword(s):  
Lattice Dynamics ◽  
Extreme Environments ◽  
X Rays ◽  
Direct Imaging ◽  
Time Resolved ◽  
X Ray ◽  
Spatial And Temporal Scales ◽  
Sample Density ◽  
Inelastic Responses ◽  
Kinetic Inhibition

Under rapid high-temperature, high-pressure loading, lattices exhibit complex elastic-inelastic responses. The dynamics of these responses are challenging to measure experimentally because of high sample density and extremely small relevant spatial and temporal scales. Here, we use an x-ray free-electron laser providing simultaneous in situ direct imaging and x-ray diffraction to spatially resolve lattice dynamics of silicon under high–strain rate conditions. We present the first imaging of a new intermediate elastic feature modulating compression along the axis of applied stress, and we identify the structure, compression, and density behind each observed wave. The ultrafast probe x-rays enabled time-resolved characterization of the intermediate elastic feature, which is leveraged to constrain kinetic inhibition of the phase transformation between 2 and 4 ns. These results not only address long-standing questions about the response of silicon under extreme environments but also demonstrate the potential for ultrafast direct measurements to illuminate new lattice dynamics.

Structural dynamics of PZT thin films at the nanoscale

2005 ◽  
Vol 902 ◽  
Author(s):  
Alexei Grigoriev ◽  
Dal-Hyun Do ◽  
Dong Min Kim ◽  
Chang-Beom Eom ◽  
Bernhard Adams ◽  
...  
Keyword(s):  
Crystal Lattice ◽  
Lattice Distortion ◽  
Piezoelectric Effect ◽  
Polarization Switching ◽  
X Rays ◽  
Time Resolved ◽  
X Ray ◽  
Converse Piezoelectric Effect ◽  
Ferroelectric Capacitors ◽  
Crystal Lattice Distortion

AbstractWhen an electric field is applied to a ferroelectric the crystal lattice spacing changes as a result of the converse piezoelectric effect. Although the piezoelectric effect and polarization switching have been investigated for decades there has been no direct nanosecond-scale visualization of these phenomena in solid crystalline ferroelectrics. Synchrotron x-rays allow the polarization switching and the crystal lattice distortion to be visualized in space and time on scales of hundreds of nanometers and hundreds of picoseconds using ultrafast x-ray microdiffraction. Here we report the polarization switching visualization and polarization domain wall velocities for Pb(Zr0.45Ti0.55)O3 thin film ferroelectric capacitors studied by time-resolved x-ray microdiffraction.

scholarly journals Time-Resolved Macromolecular Crystallography at Pulsed X-ray Sources

2019 ◽  
Vol 20 (6) ◽  
pp. 1401 ◽  
Author(s):  
Marius Schmidt
Keyword(s):  
Structural Biology ◽  
Free Electron ◽  
Reaction Dynamics ◽  
X Rays ◽  
Free Electron Lasers ◽  
Macromolecular Crystallography ◽  
Time Resolved ◽  
X Ray ◽  
Methodological Aspects

The focus of structural biology is shifting from the determination of static structures to the investigation of dynamical aspects of macromolecular function. With time-resolved macromolecular crystallography (TRX), intermediates that form and decay during the macromolecular reaction can be investigated, as well as their reaction dynamics. Time-resolved crystallographic methods were initially developed at synchrotrons. However, about a decade ago, extremely brilliant, femtosecond-pulsed X-ray sources, the free electron lasers for hard X-rays, became available to a wider community. TRX is now possible with femtosecond temporal resolution. This review provides an overview of methodological aspects of TRX, and at the same time, aims to outline the frontiers of this method at modern pulsed X-ray sources.

scholarly journals Experimental and numerical study of ultra-short laser-produced collimated Cu Kα X-ray source

2017 ◽  
Vol 35 (3) ◽  
pp. 442-449 ◽  
Author(s):  
R. Rathore ◽  
V. Arora ◽  
H. Singhal ◽  
T. Mandal ◽  
J.A. Chakera ◽  
...  
Keyword(s):  
Laser Intensity ◽  
Numerical Study ◽  
Low Cost ◽  
Laser Pulses ◽  
Photon Flux ◽  
X Rays ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Short Laser Pulses

AbstractKα X-ray sources generated from the interaction of ultra-short laser pulses with solids are compact and low-cost source of ultra-short quasi-monochromatic X-rays compared with synchrotron radiation source. Development of collimated ultra-short Kα X-ray source by the interaction of 45 fs Ti:sapphire laser pulse with Cu wire target is presented in this paper. A study of the Kα source with laser parameters such as energy and pulse duration was carried out. The observed Kα X-ray photon flux was ~2.7 × 108 photons/shot at the laser intensity of ~2.8 × 1017 W cm−2. A model was developed to analyze the observed results. The Kα radiation was coupled to a polycapillary collimator to generate a collimated low divergence (0.8 mrad) X-ray beam. Such sources are useful for time-resolved X-ray diffraction and imaging studies.

Time-Resolved X-ray Shadowgraphy Experiment of Laser Ablation of Aluminum using Laser-Induced Picosecond Pulsed X-rays

1999 ◽  
Vol 38 (Part 2, No. 3A) ◽  
pp. L242-L244 ◽  
Author(s):  
Yoichiro Hironaka ◽  
Tomoharu Inoue ◽  
Yasushi Fujimoto ◽  
Kazutaka G. Nakamura ◽  
Ken-ichi Kondo ◽  
...  
Keyword(s):  
Laser Ablation ◽  
X Rays ◽  
Time Resolved ◽  
X Ray

scholarly journals Measurements of the ablation-front trajectory and low-mode nonuniformity in direct-drive implosions using x-ray self-emission shadowgraphy

2015 ◽  
Vol 3 ◽  
Author(s):  
D.T. Michel ◽  
A.K. Davis ◽  
W. Armstrong ◽  
R. Bahr ◽  
R. Epstein ◽  
...  
Keyword(s):  
Plasma Phys ◽  
X Rays ◽  
Direct Drive ◽  
Time Resolved ◽  
X Ray ◽  
Laser Facility ◽  
Omega Laser ◽  
Control Fusion ◽  
Pm 10 ◽  
Ablation Front

Self-emission x-ray shadowgraphy provides a method to measure the ablation-front trajectory and low-mode nonuniformity of a target imploded by directly illuminating a fusion capsule with laser beams. The technique uses time-resolved images of soft x-rays ( ${>}1$  keV) emitted from the coronal plasma of the target imaged onto an x-ray framing camera to determine the position of the ablation front. Methods used to accurately measure the ablation-front radius ( ${\it\delta}R=\pm 1.15~{\rm\mu}\text{m}$ ), image-to-image timing ( ${\it\delta}({\rm\Delta}t)=\pm 2.5$  ps) and absolute timing ( ${\it\delta}t=\pm 10$  ps) are presented. Angular averaging of the images provides an average radius measurement of ${\it\delta}(R_{\text{av}})=\pm 0.15~{\rm\mu}\text{m}$ and an error in velocity of ${\it\delta}V/V=\pm 3\%$ . This technique was applied on the Omega Laser Facility [Boehly et al., Opt. Commun. 133, 495 (1997)] and the National Ignition Facility [Campbell and Hogan, Plasma Phys. Control. Fusion 41, B39 (1999)].

scholarly journals Thermal behavior of single-crystal scintillators for high-speed X-ray imaging

2019 ◽  
Vol 26 (1) ◽  
pp. 205-214 ◽  
Author(s):  
Alan Kastengren
Keyword(s):  
Single Crystal ◽  
High Speed ◽  
Thermal Loading ◽  
Indirect Detection ◽  
X Rays ◽  
Time Resolved ◽  
X Ray ◽  
Damage And Failure ◽  
Light Levels ◽  
X Ray Imaging

Indirect detection of X-rays using single-crystal scintillators is a common approach for high-resolution X-ray imaging. With the high X-ray flux available from synchrotron sources and recent advances in high-speed visible-light cameras, these measurements are increasingly used to obtain time-resolved images of dynamic phenomena. The X-ray flux on the scintillator must, in many cases, be limited to avoid thermal damage and failure of the scintillator, which in turn limits the obtainable light levels from the scintillator. In this study, a transient one-dimensional numerical simulation of the temperature and stresses within three common scintillator crystals (YAG, LuAG and LSO) used for high-speed X-ray imaging is presented. Various conditions of thermal loading and convective cooling are also presented.

scholarly journals Measurements of fast electron beams and soft X-ray emission from plasma-focus experiments

Nukleonika ◽  
2016 ◽  
Vol 61 (2) ◽  
pp. 161-167 ◽  
Author(s):  
Władysław Surała ◽  
Marek J. Sadowski ◽  
Roch Kwiatkowski ◽  
Lech Jakubowski ◽  
Jarosław Żebrowski
Keyword(s):  
Plasma Focus ◽  
Fast Electron ◽  
Hot Spots ◽  
Electron Beams ◽  
Experimental Studies ◽  
Neutron Counter ◽  
X Rays ◽  
Strong Electron ◽  
Time Resolved ◽  
X Ray

Abstract The paper reports results of the recent experimental studies of pulsed electron beams and soft X-rays in plasma-focus (PF) experiments carried out within a modified PF-360U facility at the NCBJ, Poland. Particular attention was focused on time-resolved measurements of the fast electron beams by means of two different magnetic analyzers, which could record electrons of energy ranging from about 41 keV to about 715 keV in several (6 or 8) measuring channels. For discharges performed with the pure deuterium filling, many strong electron signals were recorded in all the measuring channels. Those signals were well correlated with the first hard X-ray pulse detected by an external scintillation neutron-counter. In some of the analyzer channels, electron spikes (lasting about dozens of nanoseconds) and appearing in different instants after the current peculiarity (so-called current dip) were also recorded. For several discharges, fast ion beams, which were emitted along the z-axis and recorded with nuclear track detectors, were also investigated. Those measurements confirmed a multibeam character of the ion emission. The time-integrated soft X-ray images, which were taken side-on by means of a pinhole camera and sensitive X-ray films, showed the appearance of some filamentary structures and so-called hot spots. The application of small amounts of admixtures of different heavy noble gases, i.e. of argon (4.8% volumetric), krypton (1.6% volumetric), or xenon (0.8% volumetric), decreased intensity of the recorded electron beams, but increased intensity of the soft X-ray emission and showed more distinct and numerous hot spots. The recorded electron spikes have been explained as signals produced by quasi-mono-energetic microbeams emitted from tiny sources (probably plasma diodes), which can be formed near the observed hot spots.

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