A5086103515- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Neutrino Physics Research
- Particle Accelerators and Free-Electron Lasers
- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- Astrophysics and Cosmic Phenomena
- Medical Imaging Techniques and Applications
- Atomic and Subatomic Physics Research
- Particle accelerators and beam dynamics
- Computational Physics and Python Applications
- Radio Astronomy Observations and Technology
- Superconducting Materials and Applications
- Black Holes and Theoretical Physics
- Nuclear physics research studies
- Laser-Plasma Interactions and Diagnostics
- Advanced X-ray Imaging Techniques
- Radiation Detection and Scintillator Technologies
- Laser-Matter Interactions and Applications
- Gyrotron and Vacuum Electronics Research
- Cosmology and Gravitation Theories
- Distributed and Parallel Computing Systems
- Radiation Therapy and Dosimetry
- Advanced Data Storage Technologies
SLAC National Accelerator Laboratory
2015-2024
Stanford University
2006-2023
Menlo School
2006-2021
IMDEA Materials
2020
Colorado School of Mines
2020
Los Alamos National Laboratory
2020
Argonne National Laboratory
2020
Laboratoire d’Annecy de Physique des Particules
2002-2018
Istituto Nazionale di Fisica Nucleare, Sezione di Bari
2018
University of the Basque Country
2018
Ultrafast electron probes are powerful tools, complementary to x-ray free-electron lasers, used study structural dynamics in material, chemical, and biological sciences. High brightness, relativistic beams with femtosecond pulse duration can resolve details of the dynamic processes on atomic time length scales. SLAC National Accelerator Laboratory recently launched Electron Diffraction (UED) microscopy Initiative aiming at developing next generation ultrafast scattering instruments. As first...
We report on observations of coherent, impulsive radio Cherenkov radiation from electromagnetic showers in solid ice. This is the first observation Askaryan effect As part complete validation process for ANITA experiment, we performed an experiment at Stanford Linear Accelerator Center June 2006 using a 7.5 metric ton ice target. measure time large-scale angular dependence pattern, major factor determining solid-angle acceptance ultrahigh-energy neutrino detectors.
We report the first experimental demonstration of echo-enabled harmonic generation technique, which holds great promise for high-power, fully coherent short-wavelength radiation. In this experiment, radiation at 3rd and 4th harmonics second seed laser is generated from so-called beam echo effect. The experiment confirms physics behind technique paves way applying seeded x-ray free electron lasers.
Observing the motion of nuclear wavepackets during a molecular reaction, in both space and time, is crucial for understanding controlling outcome photoinduced chemical reactions. We have imaged vibrational wavepacket isolated iodine molecules using ultrafast electron diffraction with relativistic electrons. The time-varying interatomic distance was measured precision 0.07 {\AA} temporal resolution 230 fs full-width at half-maximum (FWHM). method not only sensitive to position but also shape...
We report the observation of 16 cosmic ray events with a mean energy $1.5\ifmmode\times\else\texttimes\fi{}{10}^{19}\text{ }\text{ }\mathrm{eV}$ via radio pulses originating from interaction air shower Antarctic geomagnetic field, process known as geosynchrotron emission. present measurements in 300--900 MHz range, which are first self-triggered, ultrawide band, far-field, and highest sample collected technique. Their properties inconsistent current ground-based models. The emission is 100%...
We report on four radio-detected cosmic-ray (CR) or CR-like events observed with the Antarctic Impulsive Transient Antenna (ANITA), a NASA-sponsored long-duration balloon payload. Two of were previously identified as stratospheric CR air showers during ANITA-I flight. A third was detected ANITA-II Here we characteristics these three unusual events, which develop nearly horizontally, 20-30~km above surface Earth. In addition, fourth steeply upward-pointing radio event has consistent primary...
We report on an upward traveling, radio-detected cosmic-ray-like impulsive event with characteristics closely matching extensive air shower. This event, observed in the third flight of Antarctic Impulsive Transient Antenna (ANITA), a NASA-sponsored long-duration balloon payload, is consistent similar reported previous flight. These events could be produced by atmospheric decay upward-propagating τ lepton ν_{τ} interaction, although their relatively steep arrival angles create tension...
Abstract Imaging changes in molecular geometries on their natural femtosecond timescale with sub-Angström spatial precision is one of the critical challenges chemical sciences, as nuclear geometry determine reactivity. For photoexcited molecules, dynamics photoenergy conversion path and efficiency. Here we report a gas-phase electron diffraction experiment using megaelectronvolt (MeV) electrons, where captured rotational wavepacket nonadiabatically laser-aligned nitrogen molecules. We...
The National User Facility for Advanced Accelerator Experimental Tests II (FACET-II) at SLAC Laboratory expands upon the experiments conducted FACET. Its purpose is to build decades-long experience developed conducting accelerator R in areas of advanced acceleration and coherent radiation techniques with high-energy electron positron beams. This paper summarizes motivations design resulting capabilities FACET-II facility.
Abstract Plasma wakefield accelerators have been used to accelerate electron and positron particle beams with gradients that are orders of magnitude larger than those achieved in conventional accelerators. In addition being accelerated by the plasma wakefield, beam particles also experience strong transverse forces may disrupt quality. Hollow channels proposed as a technique for generating accelerating fields without forces. Here we demonstrate method creating an extended hollow channel...
Two-dimensional materials are subject to intrinsic and dynamic rippling that modulates their optoelectronic electromechanical properties. Here, we directly visualize the dynamics of these processes within monolayer transition metal dichalcogenide MoS2 using femtosecond electron scattering techniques as a real-time probe with atomic-scale resolution. We show optical excitation induces large-amplitude in-plane displacements ultrafast wrinkling on nanometer length-scales, developing picosecond...
The ANtarctic Impulsive Transient Antenna (ANITA) NASA long-duration balloon payload completed its fourth flight in December 2016, after 28 days of time. ANITA is sensitive to impulsive broadband radio emission from interactions ultrahigh-energy neutrinos polar ice (Askaryan emission). We present the results two separate blind analyses searching for signals Askaryan data ANITA. more analysis, with a better expected limit, has background estimate ${0.64}_{\ensuremath{-}0.45}^{+0.69}$ and an...
The Payload for Ultrahigh Energy Observations (PUEO) long-duration balloon experiment is designed to have world-leading sensitivity ultrahigh-energy neutrinos at energies above 1 EeV. Probing this energy region essential understanding the extreme-energy universe all distance scales. PUEO leverages experience from and supersedes successful Antarctic Impulsive Transient Antenna (ANITA) program, with an improved design that drastically improves by more than order of magnitude below 30 will...
We report initial results of the first flight Antarctic Impulsive Transient Antenna (ANITA-1) 2006-2007 Long Duration Balloon flight, which searched for evidence a diffuse flux cosmic neutrinos above energies E(nu) approximately 3 x 10(18) eV. ANITA-1 flew 35 days looking radio impulses due to Askaryan effect in neutrino-induced electromagnetic showers within ice sheets. here on our analysis, was performed as blind search data. No neutrino candidates are seen, with no detected physics...
The Antarctic Impulsive Transient Antenna (ANITA), a NASA long-duration balloon payload, searches for radio emission from interactions of ultra-high-energy neutrinos in polar ice. third flight ANITA (ANITA-III) was launched December 2014 and completed 22-day flight. We present the results three analyses searching Askaryan neutrino origin. In most sensitive analyses, we find one event signal region on an expected priori background $0.7^{+0.5}_{-0.3}$. Though consistent with estimate,...
Echo-enabled harmonic generation free electron lasers hold great promise for the of fully coherent radiation in x-ray wavelengths. Here we report first evidence high harmonics from echo-enabled technique realistic scenario where laser energy modulation is comparable to beam slice spread. In this experiment, at seventh second seed generated when amplitude about 2-3 times The experiment confirms underlying physics and may have a strong impact on emerging seeded that are capable generating...