J. T. Moody
A5033379802- Laser-Plasma Interactions and Diagnostics
- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Laser-Matter Interactions and Applications
- Magnetic confinement fusion research
- Advanced X-ray Imaging Techniques
- Laser Design and Applications
- Atomic and Molecular Physics
- Photocathodes and Microchannel Plates
- Advanced Electron Microscopy Techniques and Applications
- Laser-induced spectroscopy and plasma
- Terahertz technology and applications
- Gyrotron and Vacuum Electronics Research
- Electron and X-Ray Spectroscopy Techniques
- Particle Detector Development and Performance
- Crystallography and Radiation Phenomena
- Plasma Diagnostics and Applications
- Solar and Space Plasma Dynamics
- Atomic and Subatomic Physics Research
- Superconducting Materials and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- GaN-based semiconductor devices and materials
- Nuclear Physics and Applications
- Ionosphere and magnetosphere dynamics
- Biblical Studies and Interpretation
Max Planck Institute for Physics
2016-2023
Campbell Collaboration
2022
Microsoft Research (United Kingdom)
2020
Max Planck Society
2015-2019
Google (United States)
2019
University of California, Los Angeles
2009-2016
European Organization for Nuclear Research
2016
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati
2007
High energy particle accelerators have been crucial in providing a deeper understanding of fundamental particles and the forces that govern their interactions. In order to increase or reduce size accelerator, new acceleration schemes need be developed. Plasma wakefield acceleration, which electrons plasma are excited, leading strong electric fields, is one such promising novel technique. Pioneering experiments shown an intense laser pulse electron bunch traversing plasma, drives fields 10s...
The Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) aims at studying plasma wakefield generation and electron acceleration driven by proton bunches. It is a proof-of-principle R&D experiment CERN the world׳s first experiment. AWAKE will be installed in former CNGS facility uses 400 GeV/c beam bunches from SPS. experiments focus on self-modulation instability of long (rms ~12 cm) bunch plasma. These are planned for end 2016. Later, 2017/2018, low energy (~15 MeV)...
For 40 years, uniformly filled ellipsoidal beam distributions have been studied theoretically, as they hold the promise of generating self-fields linear in coordinate offset all three directions. Recently, a scheme for producing such distributions, based on strong longitudinal expansion an initially very short under its own space-charge forces, has proposed. In this Letter we present experimental demonstration scheme, obtained by illuminating cathode rf photogun with ultrashort laser pulse...
We report the experimental demonstration of time-resolved relativistic electron diffraction. Single shot diffraction patterns from a single crystal gold sample were recorded using ultrashort 3.5 MeV bunches radio frequency photoinjector. By scanning pump pulse time-delay, we studied Bragg peaks amplitude change due to laser-induced melting sample. The observed time scale matches one predicted simple two temperature model heating thin foil. Time-resolved megaelectronvolt beams with 107...
We give direct experimental evidence for the observation of full transverse self-modulation a long, relativistic proton bunch propagating through dense plasma. The exits plasma with periodic density modulation resulting from radial wakefield effects. show that is seeded by ionization front created using an intense laser pulse copropagating bunch. extends over length following seed point. By varying one order magnitude, we frequency scales expected dependence on density, i.e., it equal to...
The seeded self-modulation of a relativistic, charged particle bunch in plasma is shown to grow both along the and plasma, resulting transverse wakefield amplitudes that far exceed initial seed values.
Single shot diffraction patterns using a 250-fs-long electron beam have been obtained at the UCLA Pegasus laboratory. High quality images with spatial resolution sufficient to distinguish closely spaced peaks in Debye–Scherrer ring pattern recorded by scattering 1.6 pC 3.5 MeV generated rf photoinjector off 100-nm-thick Au foil. Dark current and high emittance particles are removed from before sending it onto target 1 mm diameter collimating hole. These results open door study of...
In this Letter we report on the use of ultrashort infrared laser pulses to generate a copious amount electrons by copper cathode in an rf photoinjector. The charge yield verifies generalized Fowler-Dubridge theory for multiphoton photoemission. emission is verified be prompt using two pulse autocorrelation technique. thermal emittance associated with excess kinetic energy from process comparable one measured frequency tripled uv pulses. high field gun, up 50 pC can extracted 80 fs long,...
AWAKE is a proton-driven plasma wakefield acceleration experiment. % We show that the experimental setup briefly described here ready for systematic study of seeded self-modulation 400\,GeV proton bunch in 10\,m-long rubidium with density adjustable from 1 to 10$\times10^{14}$\,cm$^{-3}$. short laser pulse used ionization vapor propagates all way along column, suggesting full vapor. occurs bunch, at time and follows affects bunch.
Plasma wakefield acceleration is a promising technology to reduce the size of particle accelerators. The use high energy protons drive wakefields in plasma has been demonstrated during Run 1 AWAKE programme at CERN. Protons 400 GeV drove that accelerated electrons 2 under 10 m plasma. collaboration now embarking on with main aims demonstrate stable accelerating gradients 0.5–1 GV/m, preserve emittance electron bunches and develop sources scalable 100s metres beyond. By end 2, scheme should...
In this paper we report on the experimental demonstration of using relativistic electron diffraction and an radiofrequency deflecting cavity to capture in a single shot entire time-history ultrafast laser-induced heating melting crystal gold sample. By recording time variation Bragg peaks streak image 16 ps long beam it is possible reconstruct with 400 fs temporal resolution evolution sample structure induced by 35 mJ/cm2 nm laser pump pulse.
A long, narrow, relativistic charged particle bunch propagating in plasma is subject to the self-modulation (SM) instability. We show that SM of a proton can be seeded by wakefields driven preceding electron bunch. timing reproducibility and control are at level small fraction modulation period. With this seeding method, we independently amplitude seed with charge growth rate Seeding leads larger than instability case.
We use a relativistic ionization front to provide various initial transverse wakefield amplitudes for the self-modulation of long proton bunch in plasma. show experimentally that, with sufficient amplitude [$\ensuremath{\ge}(4.1\ifmmode\pm\else\textpm\fi{}0.4)\text{ }\text{ }\mathrm{MV}/\mathrm{m}$], phase modulation along is reproducible from event event, 3%--7% (of $2\ensuremath{\pi}$) rms variations all bunch. The not lower amplitudes. observe transition between these two regimes. Phase...
In this paper we study a new geometry setup for electro-optic sampling (EOS) where the electron beam runs parallel to $⟨110⟩$ face of ZnTe crystal and probe laser is perpendicular it path. The simple used encode time-of-arrival information $3.5\text{ }\text{ }\mathrm{MeV}<10\text{ }\mathrm{pC}$ bunch on spatial profile pulse. electric field lines inside dielectric bend at an angle due relatively large ($n\ensuremath{\sim}3$) index refraction crystal. We found theoretically experimentally...
Using an experimental scheme based on a vertically deflecting rf deflector and horizontally dispersing dipole, we characterize the longitudinal phase space of beam in blow-out regime at UCLA Pegasus photoinjector. Because achievement unprecedented resolution both time (50 fs) energy (1.0 keV), are able to demonstrate some important properties beams created this such as extremely low emittance, large temporal chirp, degrading effects cathode image charge which eventually leads poorer quality....
The AWAKE experiment requires an automated online rubidium (Rb) plasma density and gradient diagnostic for densities between 1 10⋅1014 cm−3. A linear along the source at percent level may be useful to improve electron acceleration process. Because of full laser ionization Rb vapor Rb+ within a radius mm, equals density. We measure both ends source, with high precision using, white light interferometry. At either end, broadband passes remotely controlled Mach–Zehnder interferometer built out...
Pulsed laser deposition (PLD) has been proposed several years ago as a suitable technique to deposit pure Mg film over radio frequency (rf) gun Cu backflange in order obtain high efficiency photocathode surface for the generation of brightness electron beams. In this paper we report preliminary experimental results on emission properties PLD grown within electric field gradients rf showing effects conditioning process cathode surface. Even though cleaning should be performed sample remove...
The AWAKE Collaboration has been formed in order to demonstrate proton-driven plasma wakefield acceleration for the first time. This technique could lead future colliders of high energy but a much reduced length when compared proposed linear accelerators. CERN SPS proton beam CNGS facility will be injected into 10 m cell where long bunches modulated significantly shorter micro-bunches. These micro-bunches then initiate strong with peak fields above 1 GV/m that harnessed accelerate bunch...
We study experimentally the longitudinal and transverse wakefields driven by a highly relativistic proton bunch during self-modulation in plasma. show that wakefields' growth amplitude increase with increasing seed as well charge using maximum radius of distribution measured on screen downstream from externally injecting electrons measuring their final energy. Measurements agree trends predicted theory numerical simulations validate our understanding development self-modulation. Experiments...
Abstract In 2017, AWAKE demonstrated the seeded self-modulation (SSM) of a 400 GeV proton beam from Super Proton Synchrotron at CERN. The angular distribution protons deflected due to SSM is quantitative measure process, which agrees with simulations by two-dimensional (axisymmetric) particle-in-cell code LCODE about 5%. agreement achieved in population scans two selected plasma densities and scan longitudinal density gradient. reached only case wide enough simulation box (several...
Abstract Radio-frequency (RF) photoinjector-based relativistic ultrafast electron diffraction (UED) is a promising new technique that has the potential to probe structural changes at atomic scale with sub-100 fs temporal resolution in single shot. We analyze limitations on and spatial of this considering operating parameters standard 1.6 cell RF gun (which photoinjector used for first experimental tests UED Stanford Linear Accelerator Center; University California, Los Angeles; Brookhaven...