M. G. Gorman
A5086197985- High-pressure geophysics and materials
- Laser-Plasma Interactions and Diagnostics
- Diamond and Carbon-based Materials Research
- Ion-surface interactions and analysis
- Nuclear Materials and Properties
- Crystal Structures and Properties
- Metal and Thin Film Mechanics
- X-ray Diffraction in Crystallography
- Crystallography and molecular interactions
- Energetic Materials and Combustion
- Laser-induced spectroscopy and plasma
- Advanced X-ray Imaging Techniques
- Boron and Carbon Nanomaterials Research
- X-ray Spectroscopy and Fluorescence Analysis
- Nuclear Physics and Applications
- Atomic and Molecular Physics
- Rare-earth and actinide compounds
- Laser Design and Applications
- Planetary Science and Exploration
- Laser-Matter Interactions and Applications
- Adhesion, Friction, and Surface Interactions
- High-Velocity Impact and Material Behavior
- Laser Material Processing Techniques
- Advanced Optical Sensing Technologies
- Particle Detector Development and Performance
Lawrence Livermore National Laboratory
2019-2025
Fusion UK
2025
Johns Hopkins University
2022
General Atomics (United States)
2021
University of Edinburgh
2015-2019
We combined laser shock compression with in situ x-ray diffraction to probe the crystallographic state of gold (Au) on its principal Hugoniot. Au has long been recognized as an important calibration standard diamond anvil cell experiments due stability face-centered cubic (fcc) structure extremely high pressures ($P\text{ }>600\text{ }\text{ }\mathrm{GPa}$ at 300 K). This is contrast density functional theory and first principles calculations high-pressure phases that predict a variety...
The melting of bismuth in response to shock compression has been studied using situ femtosecond x-ray diffraction at an free electron laser. Both solid-solid and solid-liquid phase transitions are documented changes discrete peaks the emergence broad, liquid scattering upon release from pressures up 14 GPa. transformation solid state is found occur less than 3 ns, very much faster previously believed. These results first quantitative measurements a material obtained on diffraction, provide...
Magnesium oxide (MgO) is a major component of the Earth’s mantle and expected to play similar role in mantles large rocky exoplanets. At extreme pressures, MgO transitions from NaCl B 1 crystal structure CsCl 2 structure, which may have implications for exoplanetary deep dynamics. In this study, we constrain phase diagram with laser-compression along shock Hugoniot, simultaneous measurements density, pressure, temperature. We identify transition between 397 425 gigapascal (around 9700...
Using x-ray diffraction at the Linac Coherent Light Source free-electron laser, we have determined simultaneously and self-consistently phase transitions equation of state (EOS) lightest transition metal, scandium, under shock compression. On compression scandium undergoes a structural between 32 35 GPa to same bcc structure seen high temperatures ambient pressures, then further 46 incommensurate host-guest polymorph found above 21 in static room temperature. Shock melting is observed 53 72...
We present the development of an experimental platform that can collect four frames x-ray diffraction data along a single line sight during laser-driven, dynamic-compression experiments at National Ignition Facility. The is comprised diagnostic imager built around ultrafast sensors with 2-ns integration time, custom target assembly serves also to shield imager, and 10-ns duration, quasi-monochromatic source produced by laser-generated plasma. demonstrate performance for Pb ramp compressed...
X-ray free electron laser (XFEL) sources coupled to high-power systems offer an avenue study the structural dynamics of materials at extreme pressures and temperatures. The recent commissioning DiPOLE 100-X on high energy density (HED) instrument European XFEL represents state-of-the-art in combining x-ray diffraction with compression, allowing for compressed be probed unprecedented detail. Here, we report quantitative measurements molten Sn 85(5) GPa ∼3500 K. capabilities HED enable liquid...
Bismuth has long been a prototypical system for investigating phase transformations and melting at high pressure. Despite decades of experimental study, however, the lattice-level response Bi to rapid (shock) compression relationship between structures occurring dynamically those observed during slow (static) compression, are still not clearly understood. We have determined structural shock-compressed 68 GPa using femtosecond X-ray diffraction, thereby revealing transition sequence...
Ultrafast x-ray diffraction at the LCLS free electron laser has been used to resolve structural behavior of antimony under shock compression 59 GPa. Antimony is seen transform incommensurate, host-guest phase Sb-II $\ensuremath{\sim}11\text{ }\text{ }\mathrm{GPa}$, which forms on nanosecond timescales with ordered guest-atom chains. The high-pressure bcc Sb-III observed above $\ensuremath{\sim}15\text{ some 8 GPa lower than in static studies, and mixed Sb-III/liquid are obtained between 38...
Abstract Investigating how solid matter behaves at enormous pressures, such as those found in the deep interiors of giant planets, is a great experimental challenge. Over past decade, computational predictions have revealed that compression to terapascal pressures may bring about counter-intuitive changes structure and bonding solids quantum mechanical forces grow influence 1–6 . Although this behaviour has been observed modest highly compressible light alkali metals 7,8 , it not established...
The authors use intense laser pulses to compress solid tantalum pressures in excess of 20 million atmospheres. By combing their experimental measurements with existing high-pressure, high-temperature data on Ta, they can create an experimentally bounded equation state that is valid up multiterapascal and thousands degrees kelvin. may serve as a useful pressure standard at the extreme compressions elevated temperatures now achievable state-of-the-art static compression experiments. This work...
Recent studies show a face-centered cubic (fcc) to body-centered (bcc) transformation along the shock Hugoniot for several metals (i.e., Cu, Au, and Ag). Here, we combine laser-shock compression of Cu foils on nanosecond timescales with in situ x-ray diffraction (XRD) examine microstructural changes stress. We study fcc phase transition from bcc (pressures greater than 180 GPa). Textural analysis azimuthal intensities XRD images is consistent into through Pitsch-distortion mechanism. use...
We present 50-fs, single-shot measurements of the x-ray thermal diffuse scattering (TDS) from copper foils that have been shocked via nanosecond laser-ablation up to pressures above 135~GPa. hence deduce Debye-Waller (DW) factor, providing a temperature measurement. The targets were laser-shocked with DiPOLE 100-X laser at High Energy Density (HED) endstation European X-ray Free-Electron Laser (EuXFEL). Single pulses, photon energy 18 keV, scattered samples and recorded on Varex detectors....
We present 50-fs, single-shot measurements of the x-ray thermal diffuse scattering (TDS) from copper foils that have been shocked via nanosecond laser ablation up to pressures above ∼135 GPa. hence deduce Debye–Waller factor, providing a temperature measurement. The targets were laser-shocked with DiPOLE 100-X at High Energy Density endstation European X-ray Free-Electron Laser. Single pulses, photon energy 18 keV, scattered samples and recorded on Varex detectors. Despite being highly...
Despite making up 5-20 wt.% of Earth's predominantly iron core, the melting properties elemental nickel at core conditions remain poorly understood, due largely to a dearth experimental data. We present here an in situ X-ray diffraction study performed on laser shock-compressed samples bulk nickel, reaching pressures ~ 500 GPa. Hugoniot states were targeted using flat-top drive, with data collected Linac Coherent Light Source. Rietveld methods used determine densities shocked from measured...
Little is known regarding the liquid structure of materials compressed to extreme conditions, and even less about structures undergoing rapid compression on nanosecond timescales. Here, we report factor radial distribution function measurements tin shock 84(19) GPa. High-quality, femtosecond x-ray diffraction at Linac Coherent Light Source were used extract diffuse scattering signal. From function, find that structural evolution with increasing pressure mimics solid phase. With pressure,...
The recovery of metastable structures formed at high pressure has been a long-standing goal in the field condensed matter physics. While laser-driven compression used as method to generate novel pressure, date no high-pressure phases have quenched ambient conditions. Here we demonstrate, using situ x-ray diffraction and methods, successful quench phase which was under shock compression. We show that tailoring release path from shock-compressed state eliminate sample spall, therefore excess...
We combine nanosecond laser shock compression with in situ picosecond x-ray diffraction to provide structural data on iron up 275 GPa. constrain the extent of hcp-liquid coexistence, onset total melt, and structure within liquid phase. Our results indicate that iron, under compression, melts completely by 258(8) A coordination number analysis indicates is a simple at these pressure-temperature conditions. also perform texture between ambient body-centered-cubic (bcc) $\ensuremath{\alpha}$,...
The response of materials under dynamic compression involves a complex interplay various deformation mechanisms aimed at relieving shear stresses, yielding remarkable diversity in material behavior. In this Letter, we utilize femtosecond x-ray diffraction coupled with nanosecond laser to reveal an intricate competition between multiple shear-relieving within elemental metal. Our observations shocked-compressed single-crystal Zr indicate disorder-mediated relaxation lower pressures. Above the...
X-ray free electron laser (XFEL) sources have revolutionized our capability to study ultrafast material behavior. Using an XFEL, we revisit the structural dynamics of shock compressed bismuth, resolving transition sequence on release in unprecedented details. Unlike previous studies that found phase-transition largely adhere equilibrium phase diagram (i.e., Bi-V → Bi-III Bi-II Bi-I), results clearly reveal previously unseen, non-equilibrium behavior at these conditions. On pressure from 5...
The Scattered Light Time-history Diagnostic (SLTD) is being implemented at the National Ignition Facility (NIF) to greatly expand angular coverage of absolute scattered-light measurements for direct- and indirect-drive inertial confinement fusion (ICF) experiments. SLTD array will ultimately consist 15 units mounted a variety polar azimuthal angles on NIF target chamber, complementing existing backscatter suite. Each unit collects diffuses scattered light onto set three optical fibers, which...
This work presents a structural study of shock-compressed states in Ag to 331 GPa, accessed via laser shock compression. Structures the resulting crystalline phases and average atomic distribution liquid state are determined using situ x-ray diffraction. We employ structure factor analysis, adapted for non-monochromatic source, determine density phase from analysis diffraction data first time compressed Ag. also present detailed phases, which shows good agreement with boundaries reported...
We present measurements of diamond formation in doubly shocked Stycast 1266 epoxy (comprising C, H, Cl, N, and O) using situ x-ray diffraction. Epoxy samples were reshocked against a LiF window to pressures between 80 148 GPa experiments at the Omega Laser Facility. The pressure temperature conditions diagnosed velocimetry optical pyrometry, respectively. X-ray diffraction patterns compressed are consistent with cubic (Fd3¯m), indicating that can precipitate not only from twice-shocked CH...
The phase diagram of sodium chloride (NaCl) under laser shock compression has been studied at Linac Coherent Light Source (LCLS) the x-ray free-electron facility. Both solid–solid (B1 → B2) and solid–liquid (B2 liquid) transitions have observed along Hugoniot over nanosecond time scales. By combining structural measurements through in situ diffraction, pressure determination velocimetry, a thermal equation-of-state, shock-compressed data are used to constrain NaCl. Transformation into B2 is...
The prototypical <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:mi>α</a:mi><a:mo>→</a:mo><a:mi>ω</a:mi></a:mrow></a:math> phase transition in zirconium is an ideal test bed for our understanding of polymorphism under extreme loading conditions. After half a century study, consensus had emerged that the realized via one two distinct displacive mechanisms, depending on nature compression path. However, recent dynamic-compression experiments equipped with diffraction...