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The LCLS beam provides revolutionary capabilities for studying the transient behavior of matter in extreme conditions. The particular strength of the Matter in Extreme Conditions instrument is that it combines the unique LCLS beam with high-power optical laser beams, and a suite of dedicated diagnostics tailored for this field of science. In this p...
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... In a typical experiment, the optical beam either drives a shock wave through a target or heats it to a high temperature. The shocked or heated region is then probed with the X-rays. Since the targets are typically destroyed by the optical laser beam on each shot, many targets can be mounted and positioned in the interaction region without venting the chamber. A motorized alignment stage, with six degrees of freedom, allows for a total area of 150 mm  25 mm to mount targets. The optical and X-ray beam are aligned and overlapped on a Ce:YAG scintillator target at the interaction point. The fluorescence signal created by the optical or X-ray laser beam can be imaged with long-distance microscopes, with a resolution of 18 m m, and overlap is achieved by steering the optical beam with a motorized focusing lens. In Fig. 2 a schematic of the MEC beamline including the most important devices and their location is shown. Table 1 summarizes the specifications of the X-ray beamline, the optical laser and details of the hutch. Compared with the other hutches at LCLS, MEC distinguishes itself by virtue of its two relatively high power and high energy optical laser systems. 2.2.1. Nd:glass laser system . The front-end of the Nd:glass laser system at MEC consists of a CW cavity operating at 1054 nm. The beam is subsequently sent through an electro- optical modulator and molded to the required pulse length and shape. The modulator has a rise time of 200 ps, and intrinsic time jitter with respect to its input trigger of 20 ps. Pulse lengths from 2 ns up to 200 ns are possible. The pulse is subsequently split into two arms, further amplified, and finally frequency-doubled to 527 nm. The maximum beam energy per arm is 25 J for pulses that are 25 ns or longer. For shorter pulses, the beams are intensity-limited to approximately 1 J ns À 1 , although this is dependent on the pulse shape. The repetition rate is determined by the cool-down time of the large-diameter glass amplifiers, which is approximately 7 min. The unfocused beam size is 40 mm. The beams are typically focused with 250 mm focal-length singlet lenses and hybrid phase plates for focal spots of 100 m m, 150 m m, 250 m m and 500 m m. Alternatively, users can bring their own focusing solution. The Ti:sapphire laser at MEC has a front-end oscillator that is phase-locked to the RF of the LCLS linac to assure timing synchronization with the X-ray pulses, resulting in an arrival time jitter between the X-rays and the optical beam of approximately 150 fs RMS. The oscillator output is stretched to 150 ps and amplified in a regenerative amplifier. The output of this regenerative amplifier is compressed and sent through a cross-polarized-wave generator (XPW) to enhance the contrast and reduce the pre-pulse on the laser. The cleaned pulse is re-stretched and amplified to a final energy of 1.5 J, with a repetition rate of 5 Hz. Adaptive optics ( i.e. a deformable mirror) are installed after the final amplifier to remove any wavefront aberrations that are present. The beam is compressed in vacuum to 50 fs and sent to the chamber with a beam diameter of 50 mm and an energy of 1 J. Alternatively, the beam can be sent to a final amplifier that uses the arms of the MEC glass laser as a pump, increasing the energy to 7 J after compression, with a beam diameter of 85 mm. Cool-down time of the glass pump limits the repetition rate to one shot every seven minutes in this operation mode. More detailed information about the laser, and the way it is used and synchronized with the LCLS X-ray beam, is given by Minitti et al. (2015). The ability to focus the LCLS beam down to sub-micro- meter spots, and its coherent nature, allow for imaging applications with unprecedented spatial and temporal resolution. MEC has taken advantage of this capability to make phase-contrast images of shock waves going through a solid (Schropp et al. , 2012). For this experiment, the LCLS beam was focused with another set of Be lenses placed inside the MEC target chamber that is not part of the standard MEC beamline. The lens set has a focal length of 170 mm and focuses to a spot of nominally 85 nm (FWHM). The characterization of this spot, which is the illumination source of the phase-contrast imaging (PCI) experiment, is highly important for a quanti- tative analysis of PCI data. This step was performed using scanning coherent X-ray microscopy (often also denoted from the interaction by ptychography) (Rodenburg & Faul- diagnostics, kner, 2004; Thibault et al. , 2009; Maiden the arrival time & Rodenburg, 2009; Schropp et al. , lenses, M1 2010, 2013 a , b ). The technique is based beam, WIN is a of the MEC target on the scanning of a nano-structured of the undulator. sample through a spatially confined and coherent X-ray beam. The measurement of the far-field diffraction patterns at each scan position allows for the reconstruction of the transmission function of the sample as well as the focused LCLS beam. In Fig. 3 the results of such a ptychographic experiment are summarized. The focus size was determined to have a central spot of approximately 100 nm (FWHM). After this characterization, a sample is placed into the divergent X-ray beam at a distance of 0.2 m behind the focus. Another 3.8 m further downstream an X-ray detector is positioned in order to measure the magnified phase-contrast image of the sample. High-resolution images are obtained with sensitivity to both amplitude and phase of the X-ray transmission function of the sample. As an example, Fig. 4 shows an image of a shock wave generated by the MEC glass laser. The laser is oriented perpendicular to the X-rays and is focused on the edge of a 100 m m-thick aluminium foil. The laser is fired, and a shockwave is created when it hits the foil. After 10 ns, the X-rays arrive and capture a snap-shot of the sample. The front of the shock wave, and regions of compressed matter behind it, can clearly be distinguished with a spatial resolution better than 1 m m. In recent years, a lot of effort has gone into measuring dense matter properties at extreme conditions using X-ray Thomson scattering. The spectral analysis of the elastically and inelas- tically scattered X-rays has provided valuable information about electron density, temperature, ionization state and collective behavior (Glenzer et al. , 1999; Landen et al. , 2001; Gregori et al. , 2003; Lee et al. , 2009; Kritcher et al. , 2008; Ma et al. , 2014). However, experimental constraints due to the broadband uncollimated laser-produced X-ray sources ( i.e. backlighters) have limited the experimental accuracy, which makes distinguishing among competing theoretical models difficult. MEC offers the ability to collect highly accurate data using LCLS, revolutionizing X-ray Thomson scattering as a technique to diagnose dense plasmas. To this aim, MEC developed crystal X-ray scattering spectrometers in a von H ́mos geometry for the accurate measurement of angle-resolved scattered spectra (see Fig. 5). The spectrometer detector position can be manually adjusted to accommodate X-ray energies between 4 keV and 8 keV. Motorization of four degrees of freedom allows us to change the scattering angle in situ from 0 to 90 with 1 resolution. Cylindrically curved crystals of either highly oriented pyrolytic graphite (HOPG) (Zastrau et al. , 2012) or highly annealed pyrolytic graphite (HAPG) (Zastrau et al. , 2013) are used to efficiently record scattered spectra. The larger mosaic spread of HOPG results in roughly twice the collection efficiency compared with HAPG, while the latter improves the spectral resolution from 30 eV to 9 eV. Fig. 5( a ) shows a raw image of the scattered spectrum on an aluminium specimen recorded by the HAPG spectrometer in a forward-scattering geometry. A resolution of 9 eV with seeded LCLS operation at 8 keV clearly distinguishes the plasmon feature down-shifted from the elastic peak by approximately 20 eV. With dynamic shock compression, the shift of the plasmon peak results in a direct measurement of electron density (Fletcher et al. , 2013). The opportunity to use an X-ray free-electron laser for investigating phase transitions of materials subjected to high- pressure shocks was recognized early on (Nagler et al. , 2007). Such high-pressure shocks are routinely generated using high- energy laser systems in facilities around the world. Using diffraction from laser-produced X-rays to probe the changes in the microscopic structure of the material has been used very successfully over the last two decades on single crystals (see Loveridge-Smith et al. , 2001; Kalantar et al. , 2005; Jensen & Gupta, 2008; Murphy et al. , 2010; Suggit et al. , 2012, and references therein). However, the investigation of poly- crystalline materials with laser-produced X-ray sources is limited in applicability due to the divergent nature of these sources and the quality of the data that can be achieved. In contrast, the almost perfect collimation of LCLS in combination with its high photon flux make it an excellent source for such research (Milathianaki et al. , 2013). The combination of LCLS with the laser system that is capable of driving Mbar shocks through solid and co-located diagnostics (such as VISAR, XRTS) provides a unique platform for this research. Diffraction of the sample under test is recorded with CSPAD detectors (MEC has both CSPAD-140k and CSPAD-560k) that have been developed by Cornell University and SLAC (Blaj et al. , 2015). In Fig. 6 we show the diffraction recorded on a CSPAD-140k, from a structured Al foil of thickness 100 m m. Fig. 6( a ) shows the unshocked foil. Fig. 6( b ) shows the diffraction 20 ns after optical beam has impinged on the target, showing the growth of grains along favorable orienta- tions as well as clear evidence of lattice decompression under shock release. The method can be used to investigate phase transitions, compression and strength of materials with ...
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... It arises in contexts ranging from astrophysical objects (24)(25)(26) and planetary interiors (27)(28)(29) to inertial confinement fusion (ICF) targets on the way to ignition (30)(31)(32)(33). Creating WDM conditions requires access to specialized experimental facilities (34)(35)(36)(37)(38) that produce shortlived and nonuniform samples with low repetition rates relative to experiments at ambient conditions. These challenges are compounded by the difficulty of simultaneously characterizing the target's thermodynamic conditions and the projectile's energy loss, as well as systematic errors attendant to measuring aggregate energy losses in lieu of energy loss rates. ...
Stopping power is the rate at which a material absorbs the kinetic energy of a charged particle passing through it—one of many properties needed over a wide range of thermodynamic conditions in modeling inertial fusion implosions. First-principles stopping calculations are classically challenging because they involve the dynamics of large electronic systems far from equilibrium, with accuracies that are particularly difficult to constrain and assess in the warm-dense conditions preceding ignition. Here, we describe a protocol for using a fault-tolerant quantum computer to calculate stopping power from a first-quantized representation of the electrons and projectile. Our approach builds upon the electronic structure block encodings of Su et al. [ PRX Quant. 2 , 040332 (2021)], adapting and optimizing those algorithms to estimate observables of interest from the non-Born–Oppenheimer dynamics of multiple particle species at finite temperature. We also work out the constant factors associated with an implementation of a high-order Trotter approach to simulating a grid representation of these systems. Ultimately, we report logical qubit requirements and leading-order Toffoli costs for computing the stopping power of various projectile/target combinations relevant to interpreting and designing inertial fusion experiments. We estimate that scientifically interesting and classically intractable stopping power calculations can be quantum simulated with roughly the same number of logical qubits and about one hundred times more Toffoli gates than is required for state-of-the-art quantum simulations of industrially relevant molecules such as FeMoco or P450.
... In this case, hundreds-of-joules class lasers are used and focused to hundreds-of-micrometers-diameter spot size. The first facility of this kind opened to users has been the MEC (Matter at Extreme) station at LCLS (Linac Coherent Light Source) in USA [20,21]. Since then, two more laser facilities were coupled to XFELs sources -BL3 station at SACLA XFEL in Japan [22] and the Dipole laser at HED (High Energy Density) station at the European XFEL in Germany -and two at synchrotron sources -the Dynamic Compression Sector (DCS) at APS in USA [23] and the High Power Laser Facility at the ESRF [24]. ...
... This study demonstrates a valuable method to unravel complex material dynamics at extreme conditions. Experiments were conducted at the Matter in Extreme Conditions (MEC) instrument at the LCLS 38, 39 . We performed experiments in the so-called transverse geometry, i.e., driving a compressive wave perpendicularly to the XFEL beam and measuring the propagation of the shock front through the sample ( Figure 1a). ...
Decades of research have investigated the mechanical properties of matter under extreme conditions, exploring how materials deform, yield, and fail when subjected to high strain rates. While plasticity codes and computational methods can provide atomic-scale precision, reliable experimental benchmarks are needed to validate these models. However, for decades only bulk and surface measurements (e.g., velocimetry and reflectivity) were available to the community, and data interpretation was mainly done relying on conventional plasticity models and drawing parallels with results obtained under quasi-hydrostatic conditions. In recent years the advent of X-ray free electron lasers has provided insight into the microscopic structure of shock-compressed matter, revealing substantial differences with static compression experiments. Information at the mesoscale was, however, still missing, and the onset and propagation of the deformation at this length-scale was only accessible using computational methods; in this paper we fill that void, providing experimental data at the relevant time- and length-scales. Here, we combine imaging and structural characterization in situ using a nanosecond pump laser coupled with a femtosecond X-ray probe in a novel experimental configuration at the LCLS. Our data provides a comprehensive characterization of the deformation of silicon, a simple, yet highly debated, model system for high-strength materials. Information spanning the macroscopic and mesoscopic scale down to the lattice level allows us to resolve and directly visualize the nucleation and growth of the high-pressure phase for the first time, providing a temporal constraint on its kinetics. These novel insights are crucial to unambiguously determine how silicon yields under shock-compression, as they are able to connect the structural evolution at the atomic level with the complex multi-wave dynamic observed at the macroscopic scale, reliably benchmarking decade-old theoretical predictions.
... Indeed, most of the experiments only probe a small fraction of the excited sample as the probed region is usually required to be smaller than the pumped one and vary from few µ m to few hundreds of µ m. For example, the sample can be in the form of a 10 µ m scale diameter liquid jet 34 , or the uniformly excited region of the sample may be limited by the pump laser power and spot size to well below 100 µm 35 . This is also particularly relevant for extreme high pressure and laser heated Diamond Anvil Cell studies that are usually performed with samples measuring a few tens of microns 16,36 . ...
X-ray Absorption Spectroscopy (XAS) is a widely used X-ray diagnostic method for studying electronic and structural properties of matter. At first glance, the relatively narrow bandwidth and the highly fluctuating spectral structure of X-ray Free Electron Lasers (XFEL) sources seem to require accumulation over many shots to achieve high data quality. To date the best approach to implementing XAS at XFEL facilities has been using monochromators to scan the photon energy across the desired spectral range. While this is possible for easily reproducible samples such as liquids, it is incompatible with many important systems. Here, we demonstrate collection of single-shot XAS spectra over 10s of eV using an XFEL source, with error bars of only a few percent. We additionally show how to extend this technique over wider spectral ranges towards Extended X-ray Absorption Fine Structure measurements, by concatenating a few tens of single-shot measurements. Our results pave the way for future XAS studies at XFELs, in particular those in the femtosecond regime. This advance is envisioned to be especially important for many transient processes that can only be initiated at lower repetition rates, for difficult to reproduce excitation conditions, or for rare samples, such as those encountered in high-energy density physics.
... It arises in contexts ranging from astrophysical objects [26][27][28] and planetary interiors [29][30][31] to inertial confinement fusion (ICF) targets on the way to ignition [32][33][34][35]. Creating WDM conditions requires access to specialized experimental facilities [36][37][38][39][40] that produce short-lived and non-uniform samples with low repetition rates relative to experiments at ambient conditions. These challenges are compounded by the difficulty of simultaneously characterizing the target's thermodynamic conditions and the projectile's energy loss, as well as systematic errors attendant to measuring aggregate energy losses in lieu of energy loss rates. ...
Stopping power is the rate at which a material absorbs the kinetic energy of a charged particle passing through it -- one of many properties needed over a wide range of thermodynamic conditions in modeling inertial fusion implosions. First-principles stopping calculations are classically challenging because they involve the dynamics of large electronic systems far from equilibrium, with accuracies that are particularly difficult to constrain and assess in the warm-dense conditions preceding ignition. Here, we describe a protocol for using a fault-tolerant quantum computer to calculate stopping power from a first-quantized representation of the electrons and projectile. Our approach builds upon the electronic structure block encodings of Su et al. [PRX Quantum 2, 040332 2021], adapting and optimizing those algorithms to estimate observables of interest from the non-Born-Oppenheimer dynamics of multiple particle species at finite temperature. Ultimately, we report logical qubit requirements and leading-order Toffoli costs for computing the stopping power of various projectile/target combinations relevant to interpreting and designing inertial fusion experiments. We estimate that scientifically interesting and classically intractable stopping power calculations can be quantum simulated with roughly the same number of logical qubits and about one hundred times more Toffoli gates than is required for state-of-the-art quantum simulations of industrially relevant molecules such as FeMoCo or P450.
... The recovery samples were collected during a series of experiments at the Matter in Extreme Conditions (MEC) end station of the Linac Coherent Light Source (LCLS) of the SLAC National Accelerator Laboratory [34,35], at the ID 19 beamline of the European Synchrotron Radiation Facility (ESRF) [36,37], and the Z6 endstation at the GSI Helmholtzzentrum für Schwerionenforschung GmbH [38]. A schematic of a representative set-up for all recovery experiments is illustrated in Fig. 1. ...
This work presents first insights into the dynamics of free-surface release clouds from dynamically compressed polystyrene and pyrolytic graphite at pressures up to 200 GPa, where they transform into diamond or lonsdaleite, respectively. These ejecta clouds are released into either vacuum or various types of catcher systems, and are monitored with high-speed recordings (frame rates up to 10 MHz). Molecular dynamics simulations are used to give insights to the rate of diamond preservation throughout the free expansion and catcher impact process, highlighting the challenges of diamond retrieval. Raman spectroscopy data show graphitic signatures on a catcher plate confirming that the shock-compressed polystyrene is transformed. First electron microscopy analyses of solid catcher plates yield an outstanding number of different spherical-like objects in the size range between ten(s) up to hundreds of nanometres, which are one type of two potential diamond candidates identified. The origin of some objects can unambiguously be assigned, while the history of others remains speculative.
... These images are captured over an 8 ns time frame [15][16][17][18][19][20], a unique capability that has the potential to revolutionize dynamic imaging for high-energy density physics (HEDP) experiments and other experiments studying ultrafast phenomena [20]. Previous experiments only had the capability of capturing one or two dynamic frames, which limited the analysis of sample evolution [21][22][23][24][25][26]. However, with the Icarus V2 detector, images are collected in sequence with greater temporal fidelity, providing a complete picture of the sample's dynamic evolution. ...
... Delivery of a laser shockwave to our samples required the 60J, Nd:glass laser system located at the MEC at LCLS [21,22]. This laser provided high-energy pulses at 527 nm [21] with a 10 ns flat-top profile. ...
... Delivery of a laser shockwave to our samples required the 60J, Nd:glass laser system located at the MEC at LCLS [21,22]. This laser provided high-energy pulses at 527 nm [21] with a 10 ns flat-top profile. High energy pulses were delivered as the summed contribution of four separate arms, depicted in Fig. 2(a). ...
Inertial confinement fusion (ICF) holds increasing promise as a potential source of abundant, clean energy, but has been impeded by defects such as micro-voids in the ablator layer of the fuel capsules. It is critical to understand how these micro-voids interact with the laser-driven shock waves that compress the fuel pellet. At the Matter in Extreme Conditions (MEC) instrument at the Linac Coherent Light Source (LCLS), we utilized an x-ray pulse train with ns separation, an x-ray microscope, and an ultrafast x-ray imaging (UXI) detector to image shock wave interactions with micro-voids. To minimize the high- and low-frequency variations of the captured images, we incorporated principal component analysis (PCA) and image alignment for flat-field correction. After applying these techniques we generated phase and attenuation maps from a 2D hydrodynamic radiation code (xRAGE), which were used to simulate XPCI images that we qualitatively compare with experimental images, providing a one-to-one comparison for benchmarking material performance. Moreover, we implement a transport-of-intensity (TIE) based method to obtain the average projected mass density (areal density) of our experimental images, yielding insight into how defect-bearing ablator materials alter microstructural feature evolution, material compression, and shock wave propagation on ICF-relevant time scales.
... Experiments were conducted at the Matter in Extreme Conditions (MEC) endstation of the Linac Coherent Light Source (LCLS) 48,49 ; single-crystal XRD enabled characterization of the crystal structure and microstructural changes of Si(100) under laser-driven shock compression. XRD data were acquired at time delays of 2, 5, 8, and 20ns for two compression regimes, i.e., compression up to 12.5 GPa and 19.5 GPa (Fig. 1). ...
Silicon (Si) is one of the most abundant elements on Earth, and it is the most widely used semiconductor. Despite extensive study, some properties of Si, such as its behaviour under dynamic compression, remain elusive. A detailed understanding of Si deformation is crucial for various fields, ranging from planetary science to materials design. Simulations suggest that in Si the shear stress generated during shock compression is released via a high-pressure phase transition, challenging the classical picture of relaxation via defect-mediated plasticity. However, direct evidence supporting either deformation mechanism remains elusive. Here, we use sub-picosecond, highly-monochromatic x-ray diffraction to study (100)-oriented single-crystal Si under laser-driven shock compression. We provide the first unambiguous, time-resolved picture of Si deformation at ultra-high strain rates, demonstrating the predicted shear release via phase transition. Our results resolve the longstanding controversy on silicon deformation and provide direct proof of strain rate-dependent deformation mechanisms in a non-metallic system.
... We performed the discussed experiments at two different XFEL facilities: the Matter in Extreme Conditions (MEC) endstation of the Linac Coherent Light Source (LCLS) of SLAC National Accelerator Laboratory (17,18) (Fig. 1) and the SPring-8 Angstrom Compact free electron LAser (SACLA) (19,20). At LCLS, the structural changes and density variations of compressed PET can be observed by in situ XRD and SAXS with the LCLS pulse of 9.5-keV photon energy and 50-fs duration. ...
Extreme conditions inside ice giants such as Uranus and Neptune can result in peculiar chemistry and structural transitions, e.g., the precipitation of diamonds or superionic water, as so far experimentally observed only for pure C─H and H 2 O systems, respectively. Here, we investigate a stoichiometric mixture of C and H 2 O by shock-compressing polyethylene terephthalate (PET) plastics and performing in situ x-ray probing. We observe diamond formation at pressures between 72 ± 7 and 125 ± 13 GPa at temperatures ranging from ~3500 to ~6000 K. Combining x-ray diffraction and small-angle x-ray scattering, we access the kinetics of this exotic reaction. The observed demixing of C and H 2 O suggests that diamond precipitation inside the ice giants is enhanced by oxygen, which can lead to isolated water and thus the formation of superionic structures relevant to the planets’ magnetic fields. Moreover, our measurements indicate a way of producing nanodiamonds by simple laser-driven shock compression of cheap PET plastics.
... Thus, during the planning stages of FELs such as LCLS, it was evident that siting a high-power optical laser alongside the FEL facility would provide the potential to provide novel insights into dynamically compressed matter. This realization ultimately led to the construction of the Materials in Extreme Conditions (MEC) end-station at LCLS. 87 This beamline started operations with an optical laser that could produce several 10 s of Joules of 0.53 μm light in a pulse length of order 10 ns. Each arm of this two-beam system can operate at a repetition rate of one shot every 6 min. ...
Solid-state material at high pressure is prevalent throughout the Universe, and an understanding of the structure of matter under such extreme conditions, gleaned from x-ray diffraction, has been pursued for the best part of a century. The highest pressures that can be reached to date (2 TPa) in combination with x-ray diffraction diagnosis have been achieved by dynamic compression via laser ablation [A. Lazicki et al., Nature 589, 532–535 (2021)]. The past decade has witnessed remarkable advances in x-ray technologies, with novel x-ray Free-Electron-Lasers (FELs) affording the capacity to produce high quality single-shot diffraction data on timescales below 100 fs. We provide a brief history of the field of dynamic compression, spanning from when the x-ray sources were almost always laser-plasma based, to the current state-of-the art diffraction capabilities provided by FELs. We give an overview of the physics of dynamic compression, diagnostic techniques, and the importance of understanding how the rate of compression influences the final temperatures reached. We provide illustrative examples of experiments performed on FEL facilities that are starting to give insight into how materials deform at ultrahigh strain rates, their phase diagrams, and the types of states that can be reached. We emphasize that there often appear to be differences in the crystalline phases observed between the use of static and dynamic compression techniques. We give our perspective on both the current state of this rapidly evolving field and some glimpses of how we see it developing in the near-to-medium term.
