First Name: R.
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Last Name: Tikhoplav
Full Name: R. Tikhoplav
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9 papers
| title: | Breakdown Limits on Gigavolt-per-Meter Electron-Beam-Driven Wakefields in Dielectric Structures |
| format: | journal article |
| year: | May 27, 2008 |
| 15 authors: | | | | | | | | | | | | | | | |
| abstract: | First measurements of the breakdown threshold in a dielectric subjected to GV=m wakefields produced by short (30 – 330 fs), 28.5 GeV electron bunches have been made. Fused silica tubes of 100 |
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| title: | Dielectric Wakefield Accelerator Experiments at the Saber Facility |
| format: | conference procceeding |
| conference: | PAC07 |
| year: | 2007 |
| 17 authors: | | | | | | | | | | | | | | | | | |
| abstract: | Electron bunches with the unparalleled combination of high charge, low emittances, and short time duration, as first produced at the SLAC Final Focus Test Beam (FFTB), are foreseen to be produced at the SABER facility. These types of bunches have enabled wakefield driven accelerating schemes of multi-GV/m in plasmas. In the context of the Dielectric Wakefield Accelerators (DWA) such beams, having rms bunch length as short as 20 um, have been used to drive 100 um and 200 um ID hollow tubes above 20 GV/m surface fields. These FFTB tests enabled the measurement of a breakdown threshold in fused silica (with full data analysis still ongoing) [1]. With the construction and commissioning of the SABER facility at SLAC, new experiments would be made possible to test further aspects of DWAs including materials, tube geometrical variations, direct measurements of the Cerenkov fields, and proof of acceleration in tubes >10 cm in length. This collaboration will investigate breakdown thresholds and accelerating fields in new materials including CVD diamond. Here we describe the experimental plans, beam parameters, simulations, and progress to date as well as future prospects for machines based of DWA structures. |
| keywords: | pbpl |
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| title: | RESULTS FROM THE UCLA/FNPL UNDERDENSE PLASMA LENS EXPERIMENT |
| format: | conference procceeding |
| conference: | Erice 2005 |
| year: | 2006 |
| 11 authors: | | | | | | | | | | | |
| abstract: | A gaussian underdense plasma lens with peak density 5 x 1012 cm−3 and a full width half maximum (FWHM) length of 2.2 cm has been used to focus a relativistic electron beam. This plasma lens is equivalent in strength to a quadrupole magnet with a 150 T/m field gradient. The lens focused a 15 MeV, 16 nC electron beam with initial dimensions σx,y ≈ 650 μm and σz ≈ 6.5 mm onto an optical transition radiation (OTR) screen ∼2 cm downstream of the lens. The average transverse area of the plasma focused electron beam was typically demagnified by a factor of 23. The evolution of the beam envelope in the area near the beam waist was measured for both round beams and asymmetric beams with x:y aspect ratios as large as 1:5. The light from the OTR screen in the round beam case was also imaged into a streak camera in order to directly measure the correlation between z and σ within the beam. |
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| title: | OBSERVATIONS OF UNDERDENSE PLASMA LENS FOCUSING OF |
| format: | journal article |
| year: | 2007 |
| 10 authors: | | | | | | | | | | |
| abstract: | Focusing of a 15 MeV, 19 nC electron bunch by an un- derdense plasma lens operated just beyond the threshold of the underdense condition has been demonstrated in ex- periments at the Fermilab NICADD Photoinjector Labora- tory (FNPL). The strong 1.9 cm focal-length plasma-lens focused both transverse directions simultaneously and re- duced the minimum area of the beam spot by a factor of 23. Analysis of the beam-envelope evolution observed near the beam waist shows that the spherical aberrations of this un- derdense lens are lower than those of an overdense plasma lens, as predicted by theory. Correlations between the beam charge and the properties of the beam focus corroborate this conclusion. |
| keywords: | pbpl |
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| title: | Observations of Underdense Plasma Lens Focusing of Relativistic Electron Beams |
| format: | conference procceeding |
| conference: | PAC07 |
| year: | 2007 |
| 10 authors: | | | | | | | | | | |
| abstract: | Focusing of a 15 MeV, 19 nC electron bunch by an un- derdense plasma lens operated just beyond the threshold of the underdense condition has been demonstrated in ex- periments at the Fermilab NICADD Photoinjector Labora- tory (FNPL). The strong 1.9 cm focal-length plasma-lens focused both transverse directions simultaneously and re- duced the minimum area of the beam spot by a factor of 23. Analysis of the beam-envelope evolution observed near the beam waist shows that the spherical aberrations of this un- derdense lens are lower than those of an overdense plasma lens, as predicted by theory. Correlations between the beam charge and the properties of the beam focus corroborate this conclusion. |
| keywords: | pbpl |
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| title: | The UCLA Helical Permanent-Magnet Inverse Free Electron Laser |
| format: | conference procceeding |
| conference: | PAC07 |
| year: | 2007 |
| 7 authors: | | | | | | | |
| abstract: | The Inverse Free Electron Laser (IFEL) is capable, in principle, of reaching accelerating gradients of up to 1 GV/m making it a prospective accelerator scheme for linear colliders. The Neptune IFEL at UCLA utilizes a 15 MeV Photoinjector-generated electron beam of 0.5 nC and a CO2 laser with peak energy of up to 100 J, and will be able to accelerate electrons to 100 MeV over an 80 cm long, novel helical permanent-magnet undulator. Past IFELs have been limited in their average accelerating gradient due to the Gouy phase shift caused by tight focusing of the drive laser. Here, laser guiding is implemented via an innovative Open Iris-Loaded Waveguide Structure (OILS) scheme which ensures that the laser mode size and wave front are conserved through the undulator. The results of the first phase of the experiment are discussed in this paper, including the design and construction of a short micro-bunching undulator, testing of the OILS waveguide, as well as the results of corresponding simulations. |
| keywords: | pbpl |
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| title: | Beam-driven Dielectric Wakefield Accelerating Structure as a Thz Radiation Source |
| format: | conference procceeding |
| conference: | PAC07 |
| year: | 2007 |
| 9 authors: | | | | | | | | | |
| abstract: | Experimental work is planned to study the performance of a beam-driven cylindrical dielectric wakefield accelerat- ing structure as a source of THz coherent Cerenkov radi- ation (CCR). For an appropriate choice of dielectric tube geometry and driving electron bunch parameters, the de- vice operates in a single-mode regime, producing radiation in the THz range. This source can potentially produce high power levels relative to currently available sources, with ∼50 μJ radiated energy per pulse achievable using the elec- tron beam currently in operation at the Neptune advanced accelerator laboratory at UCLA ( ∼13 MeV beam energy, ∼200 μm RMS bunch length, ∼500 pC bunch charge). Preparations underway for installation of the experiment are discussed. |
| keywords: | pbpl |
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| title: | The UCLA/FNPL Time Resolved Underdense Plasma Lens Experiment |
| format: | journal article |
| year: | 2005 |
| 11 authors: | | | | | | | | | | | |
| abstract: | A gaussian underdense plasma lens with peak density 5 × 1012cm-3and a full width half maximum (FWHM) length of 2.2 cm has been used to focus a relativistic electron beam. This plasma lens has a focusing strength equivalent to a quadrupole magnet with a 150 T/m field gradient. The lens focused a 15 MeV, 16 nC electron beam with initial dimensions σr= 500 μm and σz= 5 mm onto an optical transition radiation (OTR) screen 2 cm downstream of the lens. The average transverse area of the plasma focused electron beam was typically demagnified by a factor of 22. The light from the OTR screen was imaged into a streak camera in order to directly measure the correlation between z and σrwithin the beam. |
| keywords: | pbpl |
| Download | View | Details | edit | delete | |
| title: | DIELECTRIC WAKEFIELD ACCELERATOR EXPERIMENTS AT THE |
| format: | journal article |
| year: | |
| 17 authors: | | | | | | | | | | | | | | | | | |
| abstract: | Electron bunches with the unparalleled combination of high charge, low emittances, and short time duration, as first produced at the SLAC Final Focus Test Beam (FFTB), are foreseen to be produced at the SABER facility. These types of bunches have enabled wakefield driven accelerating schemes of multi-GV/m in plasmas. In the context of the Dielectric Wakefield Accelerators (DWA) such beams, having rms bunch length as short as 20 um, have been used to drive 100 um and 200 um ID hollow tubes above 20 GV/m surface fields. These FFTB tests enabled the measurement of a breakdown threshold in fused silica (with full data analysis still ongoing) [1]. With the construction and commissioning of the SABER facility at SLAC, new experiments would be made possible to test further aspects of DWAs including materials, tube geometrical variations, direct measurements of the Cerenkov fields, and proof of acceleration in tubes >10 cm in length. This collaboration will investigate breakdown thresholds and accelerating fields in new materials including CVD diamond. Here we describe the experimental plans, beam parameters, simulations, and progress to date as well as future prospects for machines based of DWA structures. |
| keywords: | pbpl |
| Download | View | Details | edit | delete | |