The Experts below are selected from a list of 2853 Experts worldwide ranked by ideXlab platform
Xiaozhe Shen - One of the best experts on this subject based on the ideXlab platform.
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photodissociation of aqueous i 3 observed with liquid phase ultrafast mega Electron Volt Electron diffraction
2020Co-Authors: Xiaozhe Shen, J P F Nunes, Kathryn Ledbetter, Mingfu Lin, Michael Kozina, Elisa Biasin, Martin Centurion, Kelly J Gaffney, Jie YangAbstract:Developing femtosecond resolution methods for directly observing structural dynamics is critical to understanding complex photochemical reaction mechanisms in solution. We have used two recent developments, ultrafast mega-Electron-Volt Electron sources and vacuum compatible sub-micron thick liquid sheet jets, to enable liquid-phase ultrafast Electron diffraction (LUED). We have demonstrated the viability of LUED by investigating the photodissociation of tri-iodide initiated with a 400 nm laser pulse. This has enabled the average speed of the bond expansion to be measured during the first 750 fs of dissociation and the geminate recombination to be directly captured on the picosecond time scale.
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femtosecond gas phase mega Electron Volt ultrafast Electron diffraction
2019Co-Authors: Xiaozhe Shen, Stephen Weathersby, J P F Nunes, Mingfu Lin, Jie Yang, R K Jobe, Bryan Moore, Mario Niebuhr, Thomas J A Wolf, Charles YonedaAbstract:The development of ultrafast gas Electron diffraction with nonrelativistic Electrons has enabled the determination of molecular structures with atomic spatial resolution. It has, however, been challenging to break the picosecond temporal resolution barrier and achieve the goal that has long been envisioned—making space- and-time resolved molecular movies of chemical reaction in the gas-phase. Recently, an ultrafast Electron diffraction (UED) apparatus using mega-Electron-Volt (MeV) Electrons was developed at the SLAC National Accelerator Laboratory for imaging ultrafast structural dynamics of molecules in the gas phase. The SLAC gas-phase MeV UED has achieved 65 fs root mean square temporal resolution, 0.63 A spatial resolution, and 0.22 A−1 reciprocal-space resolution. Such high spatial-temporal resolution has enabled the capturing of real-time molecular movies of fundamental photochemical mechanisms, such as chemical bond breaking, ring opening, and a nuclear wave packet crossing a conical intersection. In this paper, the design that enables the high spatial-temporal resolution of the SLAC gas phase MeV UED is presented. The compact design of the differential pump section of the SLAC gas phase MeV UED realized five orders-of-magnitude vacuum isolation between the Electron source and gas sample chamber. The spatial resolution, temporal resolution, and long-term stability of the apparatus are systematically characterized.
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ultrafast mega Electron Volt gas phase Electron diffraction at slac national accelerator laboratory
2018Co-Authors: Xiaozhe Shen, Stephen Weathersby, Xijie Wang, Jie YangAbstract:Ultrashort mega-Electron-Volt (MeV) Electron beams from radio-frequency (rf) photoinjectors have recently attracted strong interests for application in ultrafast gas-phase Electron diffraction (UGED). Such high-brightness Electron beams are capable of providing 100-fs level temporal resolution and sub-Angstrom level spatial resolution to capture the ultrafast structural dynamics from photoexcited gas molecules. To experimentally demonstrate such an ultrafast Electron scattering instrument, a high performance UGED system has been commissioned at SLAC National Accelerator Laboratory. The UGED instrument produces 3.7 MeV Electron beams with 2 fC beam charge at 180-Hz repetition rate. The temporal resolution is characterized to be 150 fs full-width-at-half-maximum (FWHM), while the spatial resolution is measured to be 0.76 A FWHM. The UGED instrument also demonstrates outstanding performance in vacuum, rf, and Electron beam pointing stability. Details of the performance of the SLAC MeV UGED system is reported in this paper.
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a terahertz pump mega Electron Volt ultrafast Electron diffraction probe apparatus at the slac accelerator structure test area facility
2018Co-Authors: Benjamin K Oforiokai, A H Reid, R K Jobe, M Hoffmann, S Edstrom, Ehren Mannebach, Su Ji Park, Wayne Polzin, Xiaozhe ShenAbstract:We describe a new experimental setup capable of measuring structural dynamics following intense terahertz excitation. This system, developed at the SLAC Accelerator Structure Test Area facility, uses a high-energy ultrafast laser to produce intense terahertz pulses and femtosecond Electron bunches that are accelerated to mega-Electron-Volt kinetic energies. The focused terahertz pulses have electric fields in excess of 600 kV/cm, and the resulting structural dynamics can be followed by Electron diffraction. We also present some examples demonstrating its implementation where interactions between the THz pulses and the Electron bunch are used to characterize the spatial and temporal characteristics of the THz field.
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femtosecond mega Electron Volt Electron microdiffraction
2018Co-Authors: Xiaozhe Shen, Ulf Lundstrom, T J Lane, A H Reid, Stephen Weathersby, Xijie WangAbstract:Abstract To understand and control the basic functions of physical, chemical and biological processes from micron to nano-meter scale, an instrument capable of visualizing transient structural changes of inhomogeneous materials with atomic spatial and temporal resolutions, is required. One such technique is femtosecond Electron microdiffraction, in which a short Electron pulse with femtosecond-scale duration is focused into a micron-scale spot and used to obtain diffraction images to resolve ultrafast structural dynamics over a localized crystalline domain. In this letter, we report the experimental demonstration of time-resolved mega-Electron-Volt Electron microdiffraction which achieves a 5 μm root-mean-square (rms) beam size on the sample and a 110 fs rms temporal resolution. Using pulses of 10k Electrons at 4.2 MeV energy with a normalized emittance 3 nm-rad, we obtained high quality diffraction from a single 10 μm paraffin ( C 44 H 90 ) crystal. The phonon softening mode in optical-pumped polycrystalline Bi was also time-resolved, demonstrating the temporal resolution limits of the instrument. This new characterization capability will open many research opportunities in material and biological sciences.
Kathryn Ledbetter - One of the best experts on this subject based on the ideXlab platform.
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liquid phase mega Electron Volt ultrafast Electron diffraction
2021Co-Authors: J P F Nunes, Kathryn Ledbetter, Mingfu Lin, Michael Kozina, Elisa Biasin, Martin Centurion, M Dunning, Serge Guillet, K Jobe, Yusong LiuAbstract:The conversion of light into chemical and mechanical energy mediates many important processes in nature, e.g. vision, photosynthesis and DNA photodamage. To understand the structure-function relationships regulating such processes one must strive to study them in their natural environment, i.e. in the liquid-phase. This presentation reports on the design of a novel Ultrafast Electron Diffraction instrument capable of resolving structural dynamics in liquid samples. The capabilities of this instrument are showcased in the study of water, where its structure was resolved up to the 3rd hydration shell with 0.6 A spatial resolution, and dynamics were resolved with 200 fs resolution.
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photodissociation of aqueous i 3 observed with liquid phase ultrafast mega Electron Volt Electron diffraction
2020Co-Authors: Xiaozhe Shen, J P F Nunes, Kathryn Ledbetter, Mingfu Lin, Michael Kozina, Elisa Biasin, Martin Centurion, Kelly J Gaffney, Jie YangAbstract:Developing femtosecond resolution methods for directly observing structural dynamics is critical to understanding complex photochemical reaction mechanisms in solution. We have used two recent developments, ultrafast mega-Electron-Volt Electron sources and vacuum compatible sub-micron thick liquid sheet jets, to enable liquid-phase ultrafast Electron diffraction (LUED). We have demonstrated the viability of LUED by investigating the photodissociation of tri-iodide initiated with a 400 nm laser pulse. This has enabled the average speed of the bond expansion to be measured during the first 750 fs of dissociation and the geminate recombination to be directly captured on the picosecond time scale.
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liquid phase mega Electron Volt ultrafast Electron diffraction
2020Co-Authors: J P F Nunes, Kathryn Ledbetter, Mingfu Lin, Michael Kozina, Daniel P Deponte, Elisa Biasin, Martin Centurion, C J Crissman, M DunningAbstract:The conversion of light into usable chemical and mechanical energy is pivotal to several biological and chemical processes, many of which occur in solution. To understand the structure–function relationships mediating these processes, a technique with high spatial and temporal resolutions is required. Here, we report on the design and commissioning of a liquid-phase mega-Electron-Volt (MeV) ultrafast Electron diffraction instrument for the study of structural dynamics in solution. Limitations posed by the shallow penetration depth of Electrons and the resulting information loss due to multiple scattering and the technical challenge of delivering liquids to vacuum were overcome through the use of MeV Electrons and a gas-accelerated thin liquid sheet jet. To demonstrate the capabilities of this instrument, the structure of water and its network were resolved up to the 3 rd hydration shell with a spatial resolution of 0.6 A; preliminary time-resolved experiments demonstrated a temporal resolution of 200 fs.
J P F Nunes - One of the best experts on this subject based on the ideXlab platform.
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liquid phase mega Electron Volt ultrafast Electron diffraction
2021Co-Authors: J P F Nunes, Kathryn Ledbetter, Mingfu Lin, Michael Kozina, Elisa Biasin, Martin Centurion, M Dunning, Serge Guillet, K Jobe, Yusong LiuAbstract:The conversion of light into chemical and mechanical energy mediates many important processes in nature, e.g. vision, photosynthesis and DNA photodamage. To understand the structure-function relationships regulating such processes one must strive to study them in their natural environment, i.e. in the liquid-phase. This presentation reports on the design of a novel Ultrafast Electron Diffraction instrument capable of resolving structural dynamics in liquid samples. The capabilities of this instrument are showcased in the study of water, where its structure was resolved up to the 3rd hydration shell with 0.6 A spatial resolution, and dynamics were resolved with 200 fs resolution.
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photodissociation of aqueous i 3 observed with liquid phase ultrafast mega Electron Volt Electron diffraction
2020Co-Authors: Xiaozhe Shen, J P F Nunes, Kathryn Ledbetter, Mingfu Lin, Michael Kozina, Elisa Biasin, Martin Centurion, Kelly J Gaffney, Jie YangAbstract:Developing femtosecond resolution methods for directly observing structural dynamics is critical to understanding complex photochemical reaction mechanisms in solution. We have used two recent developments, ultrafast mega-Electron-Volt Electron sources and vacuum compatible sub-micron thick liquid sheet jets, to enable liquid-phase ultrafast Electron diffraction (LUED). We have demonstrated the viability of LUED by investigating the photodissociation of tri-iodide initiated with a 400 nm laser pulse. This has enabled the average speed of the bond expansion to be measured during the first 750 fs of dissociation and the geminate recombination to be directly captured on the picosecond time scale.
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liquid phase mega Electron Volt ultrafast Electron diffraction
2020Co-Authors: J P F Nunes, Kathryn Ledbetter, Mingfu Lin, Michael Kozina, Daniel P Deponte, Elisa Biasin, Martin Centurion, C J Crissman, M DunningAbstract:The conversion of light into usable chemical and mechanical energy is pivotal to several biological and chemical processes, many of which occur in solution. To understand the structure–function relationships mediating these processes, a technique with high spatial and temporal resolutions is required. Here, we report on the design and commissioning of a liquid-phase mega-Electron-Volt (MeV) ultrafast Electron diffraction instrument for the study of structural dynamics in solution. Limitations posed by the shallow penetration depth of Electrons and the resulting information loss due to multiple scattering and the technical challenge of delivering liquids to vacuum were overcome through the use of MeV Electrons and a gas-accelerated thin liquid sheet jet. To demonstrate the capabilities of this instrument, the structure of water and its network were resolved up to the 3 rd hydration shell with a spatial resolution of 0.6 A; preliminary time-resolved experiments demonstrated a temporal resolution of 200 fs.
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femtosecond gas phase mega Electron Volt ultrafast Electron diffraction
2019Co-Authors: Xiaozhe Shen, Stephen Weathersby, J P F Nunes, Mingfu Lin, Jie Yang, R K Jobe, Bryan Moore, Mario Niebuhr, Thomas J A Wolf, Charles YonedaAbstract:The development of ultrafast gas Electron diffraction with nonrelativistic Electrons has enabled the determination of molecular structures with atomic spatial resolution. It has, however, been challenging to break the picosecond temporal resolution barrier and achieve the goal that has long been envisioned—making space- and-time resolved molecular movies of chemical reaction in the gas-phase. Recently, an ultrafast Electron diffraction (UED) apparatus using mega-Electron-Volt (MeV) Electrons was developed at the SLAC National Accelerator Laboratory for imaging ultrafast structural dynamics of molecules in the gas phase. The SLAC gas-phase MeV UED has achieved 65 fs root mean square temporal resolution, 0.63 A spatial resolution, and 0.22 A−1 reciprocal-space resolution. Such high spatial-temporal resolution has enabled the capturing of real-time molecular movies of fundamental photochemical mechanisms, such as chemical bond breaking, ring opening, and a nuclear wave packet crossing a conical intersection. In this paper, the design that enables the high spatial-temporal resolution of the SLAC gas phase MeV UED is presented. The compact design of the differential pump section of the SLAC gas phase MeV UED realized five orders-of-magnitude vacuum isolation between the Electron source and gas sample chamber. The spatial resolution, temporal resolution, and long-term stability of the apparatus are systematically characterized.
R Senesi - One of the best experts on this subject based on the ideXlab platform.
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neutrons matter vii international workshop on Electron Volt neutron spectroscopy a preface to the workshop proceedings
2018Co-Authors: Giovanni Romanelli, C Andreani, M Krzystyniak, Felix Fernandezalonso, G Festa, R SenesiAbstract:We present here a collection of works reporting on the recent experimental and theoretical activities taking advantage of epithermal neutron spectroscopy, and in particular focusing on recent results presented during the VII International Workshop on Electron-Volt Neutron Spectroscopy held in Rome on 7-8 November 2018.
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neutrons matter vii international workshop on Electron Volt neutron spectroscopy
2018Co-Authors: Giovanni Romanelli, R Senesi, C Andreani, M Krzystyniak, G Festa, Felix FernandezalonsoAbstract:Science is a superb way of transcending national boundaries and political circumstances. The long-standing agreement between the Italian Consiglio Nazionale delle Ricerche (CNR) and the British Sci...
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Electron Volt neutron spectroscopy beyond fundamental systems
2017Co-Authors: C Andreani, R Senesi, M Krzystyniak, Giovanni Romanelli, Felix FernandezalonsoAbstract:This work provides an up-to-date account of the use of Electron-Volt neutron spectroscopy in materials research. This is a growing area of neutron science, capitalising upon the unique insights provided by epithermal neutrons on the behaviour and properties of an increasing number of complex materials. As such, the present work builds upon the aims and scope of a previous contribution to this journal back in 2005, whose primary focus was on a detailed description of the theoretical foundations of the technique and their application to fundamental systems [see Andreani et al., Adv. Phys. 54 (2005) p.377] A lot has happened since then, and this review intends to capture such progress in the field. With both expert and novice in mind, we start by presenting the general principles underpinning the technique and discuss recent conceptual and methodological developments. We emphasise the increasing use of the technique as a non-invasive spectroscopic probe with intrinsic mass selectivity, as well as the concurr...
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vi workshop in Electron Volt neutron spectroscopy frontiers and horizons
2014Co-Authors: Andrew G Seel, R Senesi, Felix FernandezalonsoAbstract:January 2014 saw the congregation in Abingdon (UK) of scientists from across the world, to discuss the current state and future of spectroscopy using epithermal neutrons. This meeting was the sixth in a series of workshops held in collaboration between the Science and Technology Facilities Council (UK) and the Consiglio Nazionale delle Ricerche (Italy), aimed at bringing together researchers with an interest in the use of Electron-Volt neutrons in spectroscopic studies [1]. This technique is termed Deep Inelastic Neutron Scattering (DINS), and also Neutron Compton Scattering (NCS) in reference to the analogy with Compton scattering of X-rays from Electrons. In particular, this meeting centred jointly around experimentalists and theoreticians, formulating animated discussions as to the current overview of DINS and future horizons facing the field. The use of Electron Volt neutrons for spectroscopic measurements dates back to the advent of proton-driven spallation neutron sources in the 1970s and 1980s. Following an initial scientific meeting in Los Alamos (USA) [2], the first two meetings in this series were held in Abingdon (UK) in 1995 and 1998, with subsequent meetings held in Santa Fe (USA) in 2005 [3], Oak Ridge National Laboratory (USA) in 2006 [4], and Rome, Italy; in 2010 [5]. The flagship instrument serving a continual user-programme for DINS measurements, and the main focus of this meeting, has been the VESUVIO spectrometer at ISIS [6, 7]. Subsequent instruments like SEQUOIA in the USA [8, 9] and a newer spectrometer in the Bariloche LINAC in Argentina [10, 11] have also been commissioned and began serving a growing user community. The availability of DINS measurements has extended the range of possible spectroscopic techniques that utilise neutrons into the kinematic region of high energy and momentum transfers, shown schematically in Figure 1. Spectroscopic instrument suites such as that of ISIS are thus able to probe processes on timescales across nine orders of magnitude, from quantum tunnelling and molecular diffusion up to nuclear recoil under the impulse approximation. DINS is one of the most direct techniques for probing nuclear quantum dynamics in condensed matter, with the ability to measure nuclear kinetic energies and momentum distributions of light nuclei. A major theme for current DINS research relates to the study of nuclear quantum effects, particularly regarding the non-classical behaviour of hydrogen or deuterium. This emphasis was reflected by the meeting's opening session dealing with the measurement of momentum distributions in hydrogen-bonded and aqueous systems (see Table 1). Whilst concentrating on experimental studies, data were presented from the outset alongside state-of-the-art path-integral molecular dynamics (PIMD) calculations, affording an animated discussion as to the interpretation of measured neutron Compton profiles in spatially disordered systems. The extension of DINS to heavier nuclei was visited in the second session of the meeting, under the over-arching theme of MAss-selective Neutron SpEctroscopy (MANSE). The ability of DINS to examine atomically distinct species in condensed matter has garnered interest from the chemistry and materials communities, with both binary systems and more complex materials being presented in this session. Nuclei of interest in applied materials research were highlighted, including oxygen, lithium and fluorine, alongside an assessment of current capabilities and future developments in their examination by DINS. The concluding session of the first day of the meeting was concerned with instrumentation. The detection of epithermal neutrons requires technologies unique relative to their lower-energy counterparts, and the first talk of this session outlined how detector capabilities on existing instruments has been revolutionised in recent years. Resonance detectors and techniques involving analyser-foil cycling were detailed, explaining how they have improved not only the count-rate but also the spectral resolution of instruments such as VESUVIO. Beyond NCS, the detection of nuclear resonances were also considered. An overview of VESUVIO (a time-of-flight instrument operating in so-called indirect geometry) was then given, alongside ways it could be improved upon in light of growing demands from the user community. This discussion was complemented by a presentation of the use of direct-geometry instruments such as SEQUOIA for DINS measurements, highlighting the complementarity with parallel studies on VESUVIO. The second day of the meeting was given over to the theoretical aspects of nuclear momentum distributions. Delegates were presented with the manner in which we can computationally incorporate nuclear quantum effects, along with their output in terms of 'measureables', relating to a varied range of systems. Results were presented from hydrogen-bonded liquids, ferroelectric materials, biological systems, and mixed bosonic-fermionic calculations. The ability to now approach experimental measurement with theoretical insight, and vice versa, is a sea-change in research into nuclear quantum effects. This field is a high-profile area in chemical physics and materials research, and a concerted approach by theory and experimentation allows us to explore and explain the dynamical state of matter at the atomic level in a manner previously unobtainable. Concluding each session throughout the meeting were periods of open discussion, wherein all present could comment or expand upon themes arising from the preceding talks. These discussions were then further distilled and clarified during the final section of the meeting, the 'Frontiers and Horizons' discussion, open to all present to delineate the next steps in DINS as a whole. Experimentalists and theoreticians were able to present their views on how each community could move forward to complement each other, not only separately but with specific projects and milestones in mind. These discussions have been included within these proceedings to highlight the future outlook of DINS. It is the hope of these editors that this meeting will allow spectroscopy with epithermal neutrons to further develop, explaining the very quantum nature of dynamics in condensed matter. Bringing together, as it did, international researchers in fields at the frontiers of their respective experimental and theoretical communities, we hope that the next meeting in this series will see the fruition of concepts and projects instigated by this one.
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Electron Volt neutron spectrometers
2011Co-Authors: A Pietropaolo, R SenesiAbstract:Abstract The advent of pulsed neutron sources has made available intense fluxes of epithermal neutrons (500 meV ≤E≤100 eV ). The possibility to open new investigations on condensed matter with eV neutron scattering techniques, is related to the development of methods, concepts and devices that drive, or are inspired by, emerging studies at this energy scale. Electron Volt spectrometers have undergone continuous improvements since the construction of the first prototype instruments, but in the last decade major breakthroughs have been accomplished in terms of resolution and counting statistics, leading, for example, to the direct measurement of the proton 3-D Born–Oppenheimer potential in any material, or to quantitatively probe nuclear quantum effects in hydrogen bonded systems. This paper reports on the most effective methods and concepts for energy analysis and detection, as well as devices for the optimization of Electron Volt spectrometers for different applications. This is set in the context of the progress made up to date in instrument development. Starting from early stages of development of the technique, particular emphasis will be given to the Vesuvio eV spectrometer at the ISIS neutron source, the first spectrometer where extensive scientific, as well as research and development programmes have been carried out. The potential offered by this type of instrumentation, from single particle excitations to momentum distribution studies, is then put in perspective into the emerging fields of eV spectroscopy applied to cultural heritages and neutron irradiation effects in Electronics.
Mingfu Lin - One of the best experts on this subject based on the ideXlab platform.
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liquid phase mega Electron Volt ultrafast Electron diffraction
2021Co-Authors: J P F Nunes, Kathryn Ledbetter, Mingfu Lin, Michael Kozina, Elisa Biasin, Martin Centurion, M Dunning, Serge Guillet, K Jobe, Yusong LiuAbstract:The conversion of light into chemical and mechanical energy mediates many important processes in nature, e.g. vision, photosynthesis and DNA photodamage. To understand the structure-function relationships regulating such processes one must strive to study them in their natural environment, i.e. in the liquid-phase. This presentation reports on the design of a novel Ultrafast Electron Diffraction instrument capable of resolving structural dynamics in liquid samples. The capabilities of this instrument are showcased in the study of water, where its structure was resolved up to the 3rd hydration shell with 0.6 A spatial resolution, and dynamics were resolved with 200 fs resolution.
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photodissociation of aqueous i 3 observed with liquid phase ultrafast mega Electron Volt Electron diffraction
2020Co-Authors: Xiaozhe Shen, J P F Nunes, Kathryn Ledbetter, Mingfu Lin, Michael Kozina, Elisa Biasin, Martin Centurion, Kelly J Gaffney, Jie YangAbstract:Developing femtosecond resolution methods for directly observing structural dynamics is critical to understanding complex photochemical reaction mechanisms in solution. We have used two recent developments, ultrafast mega-Electron-Volt Electron sources and vacuum compatible sub-micron thick liquid sheet jets, to enable liquid-phase ultrafast Electron diffraction (LUED). We have demonstrated the viability of LUED by investigating the photodissociation of tri-iodide initiated with a 400 nm laser pulse. This has enabled the average speed of the bond expansion to be measured during the first 750 fs of dissociation and the geminate recombination to be directly captured on the picosecond time scale.
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liquid phase mega Electron Volt ultrafast Electron diffraction
2020Co-Authors: J P F Nunes, Kathryn Ledbetter, Mingfu Lin, Michael Kozina, Daniel P Deponte, Elisa Biasin, Martin Centurion, C J Crissman, M DunningAbstract:The conversion of light into usable chemical and mechanical energy is pivotal to several biological and chemical processes, many of which occur in solution. To understand the structure–function relationships mediating these processes, a technique with high spatial and temporal resolutions is required. Here, we report on the design and commissioning of a liquid-phase mega-Electron-Volt (MeV) ultrafast Electron diffraction instrument for the study of structural dynamics in solution. Limitations posed by the shallow penetration depth of Electrons and the resulting information loss due to multiple scattering and the technical challenge of delivering liquids to vacuum were overcome through the use of MeV Electrons and a gas-accelerated thin liquid sheet jet. To demonstrate the capabilities of this instrument, the structure of water and its network were resolved up to the 3 rd hydration shell with a spatial resolution of 0.6 A; preliminary time-resolved experiments demonstrated a temporal resolution of 200 fs.
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femtosecond gas phase mega Electron Volt ultrafast Electron diffraction
2019Co-Authors: Xiaozhe Shen, Stephen Weathersby, J P F Nunes, Mingfu Lin, Jie Yang, R K Jobe, Bryan Moore, Mario Niebuhr, Thomas J A Wolf, Charles YonedaAbstract:The development of ultrafast gas Electron diffraction with nonrelativistic Electrons has enabled the determination of molecular structures with atomic spatial resolution. It has, however, been challenging to break the picosecond temporal resolution barrier and achieve the goal that has long been envisioned—making space- and-time resolved molecular movies of chemical reaction in the gas-phase. Recently, an ultrafast Electron diffraction (UED) apparatus using mega-Electron-Volt (MeV) Electrons was developed at the SLAC National Accelerator Laboratory for imaging ultrafast structural dynamics of molecules in the gas phase. The SLAC gas-phase MeV UED has achieved 65 fs root mean square temporal resolution, 0.63 A spatial resolution, and 0.22 A−1 reciprocal-space resolution. Such high spatial-temporal resolution has enabled the capturing of real-time molecular movies of fundamental photochemical mechanisms, such as chemical bond breaking, ring opening, and a nuclear wave packet crossing a conical intersection. In this paper, the design that enables the high spatial-temporal resolution of the SLAC gas phase MeV UED is presented. The compact design of the differential pump section of the SLAC gas phase MeV UED realized five orders-of-magnitude vacuum isolation between the Electron source and gas sample chamber. The spatial resolution, temporal resolution, and long-term stability of the apparatus are systematically characterized.