A5011013193- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Gyrotron and Vacuum Electronics Research
- Particle Detector Development and Performance
- Superconducting Materials and Applications
- Crystallography and Radiation Phenomena
- Muon and positron interactions and applications
- Laser-Plasma Interactions and Diagnostics
- Radiation Detection and Scintillator Technologies
- Particle physics theoretical and experimental studies
- Advanced X-ray Imaging Techniques
- Nuclear Physics and Applications
- Electron and X-Ray Spectroscopy Techniques
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Advancements in Photolithography Techniques
- Advanced Electron Microscopy Techniques and Applications
- Laser-Matter Interactions and Applications
- Nuclear materials and radiation effects
- Medical Imaging Techniques and Applications
- Laser-induced spectroscopy and plasma
- Optical Systems and Laser Technology
- Photocathodes and Microchannel Plates
- Quantum and Classical Electrodynamics
- Hydraulic and Pneumatic Systems
California Polytechnic State University
2013-2023
California State Polytechnic University
2017-2020
Aarhus University
2016
Cornell University
2000-2013
Cal Poly Corporation
2013
Alfred University
2006-2007
Stanford Synchrotron Radiation Lightsource
1993-2002
SLAC National Accelerator Laboratory
1993-2002
Stanford University
1992-2002
Menlo School
2001
We report on an experiment performing channeling and volume reflection of a high-energy electron beam using quasimosaic, bent silicon (111) crystal at the End Station A Test Beam SLAC. The uses beams 3.35 6.3 GeV. In orientation, deflections 400 μrad for both energies with about 22% efficiency are observed, while in volume-reflection deflection by 120 GeV 80 is observed 86%-95% efficiency. Quantitative measurements efficiency, surface transmission, dechanneling length taken. These first...
We present the experimental data and analysis of experiments conducted at SLAC National Accelerator Laboratory investigating processes channeling, volume-reflection volume-capture along (111) plane in a strongly bent quasimosaic silicon crystal. These phenomena were investigated 5 energies: 3.35, 4.2, 6.3, 10.5, 14.0 GeV with crystal bending radius 0.15 m, corresponding to curvatures 0.053, 0.066, 0.099, 0.16, 0.22 times critical curvature, respectively. Based on parameters fitting functions...
We demonstrate experimentally that the trident process ${e}^{\ensuremath{-}}\ensuremath{\rightarrow}{e}^{\ensuremath{-}}{e}^{+}{e}^{\ensuremath{-}}$ in a strong external field, with spatial extension comparable to effective radiation length, is well understood theoretically. The experiment, conducted at CERN, probes values for field parameter $\ensuremath{\chi}$ up 2.4. Experimental data and theoretical expectations using local constant approximation show remarkable agreement over almost 3...
An accelerated charged particle emits electromagnetic radiation. If the driving force is sufficiently strong, radiated energy becomes comparable to kinetic of and backaction emitted radiation (radiation reaction) significantly alters dynamics particle. The Landau-Lifshitz (LL) equation has been proposed as classical describe a in strong field when effects reaction are taken into account. Hitherto, experimental problem validating LL achieve fields for be important without quantum being...
We report on the first experimental observations of quasichanneling oscillations, recently seen in simulations and described theoretically. Although above-barrier particles penetrating a single crystal are generally as behaving almost an amorphous substance, distinct oscillation peaks nevertheless appear for that category. The oscillations were observed at SLAC National Accelerator Laboratory by aiming 20.35 GeV positrons electrons thin silicon bent to radius R=0.15 m, exploiting quasimosaic...
Intrabeam scattering (IBS) limits the emittance and single-bunch current that can be achieved in electron or positron storage ring colliders, damping rings, light sources. Much theoretical work on IBS exists, while theories have been validated hadron ion machines, presence of strong makes lepton machines a different phenomenon. We present results measurements at CesrTA IBS-dominated beams, compare data with theory. The beams we study parameters typical those specified for next generation...
Measurements of the beam's bunch length in Cornell Electron-Positron Storage Ring (CESR) have been made using a streak camera. The camera uses visible synchrotron radiation produced by beam to measure its longitudinal distribution. A description CESR, experimental setup, used, and systematic errors analysis techniques are described this paper. dependence distribution on current accelerating rf voltage for single CESR was measured compared with theoretical model CESR. vacuum chamber impedance...
A semiclassical approach is used to calculate radiation emission in the collision of an electron with intense focused laser pulse. The results are benchmarked numerical calculations exact a plane wave and compared predictions from locally constant field monochromatic approximations. It found that simulations employing capture features energy spectra, such as subharmonics bandwidth structure, which beyond local approaches. formation length introduced diagnostic select between approaches...
New low-impedance vacuum chambers were installed in the SLC damping rings for 1994 run after finding a single bunch instability with old chamber. Although threshold is lower new chamber, less severe, and we are now routinely operating at intensities of 4.5/spl times/10/sup 10/ particles per (ppb) compared to 3/spl ppb 1993. The chamber upgrade described, measurements length, energy spread, frequency time domain signatures presented.
Abstract The Landau–Lifshitz (LL) equation has been proposed as the classical to describe dynamics of a charged particle in strong electromagnetic field when influenced by radiation reaction. Until recently, there no clear experimental verification. However, aligned crystals have remedied situation: here, Nielsen et al CERN NA63 Collaboration (2020 Phys. Rev. D 102 052004), we report on quantitative test LL measuring emission spectra electrons and positrons penetrating single crystals....
We present branching fraction measurements of three-prong decays the τ− lepton based on data from TPC/Two-Gamma detector at SLAC PEP. The are classified according to identities charged tracks give simultaneous B[τ−→ντ K−π+π−]=0.58−0.13+0.15% and K−K+π−]=0.15−0.07+0.09%, upper limits B[τ−→ντπ−K+π−]<0.25%, K−π+K−]<0.09%, K−K+K−]<0.21%, where additional neutrals may be in each case. fractions normalized world average topological there is an estimated 20% systematic error addition listed...
The Cornell Electron-positron Storage Ring (CESR) has been converted from a High Energy Physics electron-positron collider to operate as dedicated synchrotron light source for the Synchrotron Source (CHESS) and conduct accelerator physics research test accelerator, capable of studying topics relevant future damping rings, colliders sources. Some specific that were targeted initial phase operation storage ring in this mode, labeled CesrTA (CESR Test Accelerator), included 1) tuning techniques...
At the Cornell Electron-Positron Storage Ring Test Accelerator (CesrTA) experiments have been studying interaction of electron cloud (EC) with 2.1 GeV stored and positron beams. These are intended to characterize dependence beam–EC interactions on various beam parameters, such as bunch spacing vertical chromaticity. Most were performed 30 or 45-bunch trains, at a fixed current 0.75 mA/bunch. Earlier positrons had varied between 4 56 ns three different chromaticity settings. More recent...
In this paper, we present experimental results and numerical simulations of trident production, ${e}^{\ensuremath{-}}\ensuremath{\rightarrow}{e}^{\ensuremath{-}}{e}^{+}{e}^{\ensuremath{-}}$, in a strong electromagnetic field. The experiment was conducted at CERN for the purpose probing strong-field parameter $\ensuremath{\chi}$ up to 2.4, using 200 GeV electron beam penetrating $400\text{ }\text{ }\mathrm{\ensuremath{\mu}}\mathrm{m}$ thick germanium crystal oriented along $⟨110⟩$ axis. For...
Machine performance for the running period is reviewed with an emphasis on phenomena associated large number of parasitic crossings peculiar to a single ring collider multi-bunch beams.