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Two Channel Dielectric Wake Field Accelerator
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Book Synopsis TWO-CHANNEL DIELECTRIC WAKE FIELD ACCELERATOR. by :
Download or read book TWO-CHANNEL DIELECTRIC WAKE FIELD ACCELERATOR. written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental results are reported for test beam acceleration and deflection in a two-channel, cm-scale, rectangular dielectric-lined wakefield accelerator structure energized by a 14-MeV drive beam. The dominant waveguide mode of the structure is at ≈30 GHz, and the structure is configured to exhibit a high transformer ratio (≈12:1). Accelerated bunches in the narrow secondary channel of the structure are continuously energized via Cherenkov radiation that is emitted by a drive bunch moving in the wider primary channel. Observed energy gains and losses, transverse deflections, and changes in the test bunch charge distribution compare favorably with predictions of theory.
Book Synopsis COAXIAL TWO-CHANNEL DIELECTRIC WAKE FIELD ACCELERATOR. by :
Download or read book COAXIAL TWO-CHANNEL DIELECTRIC WAKE FIELD ACCELERATOR. written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Theory, computations, and experimental apparatus are presented that describe and are intended to confirm novel properties of a coaxial two-channel dielectric wake field accelerator. In this configuration, an annular drive beam in the outer coaxial channel excites multimode wakefields which, in the inner channel, can accelerate a test beam to an energy much higher than the energy of the drive beam. This high transformer ratio is the result of judicious choice of the dielectric structure parameters, and of the phase separation between drive bunches and test bunches. A structure with cm-scale wakefields has been build for tests at the Argonne Wakefield Accelerator Laboratory, and a structure with mm-scale wakefields has been built for tests at the SLAC FACET facility. Both tests await scheduling by the respective facilities.
Book Synopsis Theory of the Dielectric Wakefield Accelerator by :
Download or read book Theory of the Dielectric Wakefield Accelerator written by and published by . This book was released on 1990 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis High-Gradient, High-Transformer-Ratio, Dielectric Wake Field Accelerator by :
Download or read book High-Gradient, High-Transformer-Ratio, Dielectric Wake Field Accelerator written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Phase I work reported here responds to DoE'ss stated need " ... to develop improved accelerator designs that can provide very high gradient (>200 MV/m for electrons ...) acceleration of intense bunches of particles." Omega-P's approach to this goal is through use of a ramped train of annular electron bunches to drive a coaxial dielectric wakefield accelerator (CDWA) structure. This approach is a direct extension of the CDWA concept from acceleration in wake fields caused by a single drive bunch, to the more efficient acceleration that we predict can be realized from a tailored (or ramped) train of several drive bunches. This is possible because of a much higher transformer ratio for the latter. The CDWA structure itself has a number of unique features, including: a high accelerating gradient G, potentially with G> 1 GeV/m; continuous energy coupling from drive to test bunches without transfer structures; inherent transverse focusing forces for particles in the accelerated bunch; highly stable motion of high charge annular drive bunches; acceptable alignment tolerances for a multi-section system. What is new in the present approach is that the coaxial dielectric structure is now to be energized by-not one-but by a short train of ramped annular-shaped drive bunches moving in the outer coaxial channel of the structure. We have shown that this allows acceleration of an electron bunch traveling along the axis in the inner channel with a markedly higher transformer ratio T than for a single drive bunch. As described in this report, the structure will be a GHz-scale prototype with cm-scale transverse dimensions that is expected to confirm principles that can be applied to the design of a future THz-scale high gradient (> 500 MV/m) accelerator with mm-scale transverse dimensions. We show here a new means to significantly increase the transformer ratio T of the device, and thereby to significantly improve its suitability as a flexible and effective component in a future high energy, high gradient accelerator facility. We predict that the T of a high gradient CDWA can be increased by a substantial factor; this enhancement is dramatically greater than what has been demonstrated heretofore. This large enhancement in T that we predict arises from using a train of three or four drive bunches in which the spacing of the bunches and their respective charges are selected according to a simple principle that requires each bunch lose energy to the wakefields at the same rate, so as not to sacrifice drive beam efficiency as would be the case if one bunch exhausted its available energy while others had not. It is anticipated that results from the study proposed here can have a direct impact on design of the dielectric accelerator in a TeV-scale collider concept, and in the accelerator for an x-ray FEL.
Download or read book קורות אילנה במעמקי הים written by and published by . This book was released on 1942 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Ultra-High Gradient Dielectric Wakefield Accelerator Experiments by :
Download or read book Ultra-High Gradient Dielectric Wakefield Accelerator Experiments written by and published by . This book was released on 2007 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultra-high gradient dielectric wakefield accelerators are a potential option for a linear collider afterburner since they are immune to the ion collapse and electron/positron asymmetry problems implicit in a plasma based afterburner. The first phase of an experiment to study the performance of dielectric Cerenkov wakefield accelerating structures at extremely high gradients in the GV/m range has been completed. The experiment took advantage of the unique SLAC FFTB electron beam and its ultra-short pulse lengths and high currents (e.g., [sigma]{sub z} = 20 [mu]m at Q = 3 nC). The FFTB electron beam was successfully focused down and sent through short lengths of fused silica capillary tubing (ID = 200 [mu]m/OD = 325 [mu]m). The pulse length of the electron beam was varied to produce a range of electric fields between 2 and 20 GV/m at the inner surface of the dielectric tubes. We observed a sharp increase in optical emissions from the capillaries in the middle part of this surface field range which we believe indicates the transition between sustainable field levels and breakdown. If this initial interpretation is correct, the surfaced fields that were sustained equate to on axis accelerating field of several GV/m. In future experiments being developed for the SLAC SABER and BNL ATF we plan to use the coherent Cerenkov radiation emitted from the capillary tube as a field strength diagnostic and demonstrate GV/m range particle energy gain.
Book Synopsis Dielectric Wakefield Accelerator Experiments at the SABER Facility by :
Download or read book Dielectric Wakefield Accelerator Experiments at the SABER Facility written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Wakefield Acceleration in Structures by :
Download or read book Wakefield Acceleration in Structures written by and published by . This book was released on 2002 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wakefield acceleration in dielectric loaded structures is discussed in this paper. We present a description of the dielectric wakefield accelerator concept, comparing some features of the collinear and the two beam accelerator configurations. The Argonne Wakefield Accelerator Facility (AWA) is discussed in detail, including major upgrades that are presently taking place. The basic features and capabilities of the facility are presented, and the dielectric wakefield acceleration results are briefly summarized. Possible variants of the two beam accelerator configuration are discussed, and work on planar dielectric structures in various institutions is presented. We conclude this report mentioning prospective achievements of dielectric wakefield accelerating structures.
Book Synopsis Experimental Plans to Explore Dielectric Wakefield Acceleration in the THZ Regime by :
Download or read book Experimental Plans to Explore Dielectric Wakefield Acceleration in the THZ Regime written by and published by . This book was released on 2011 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dielectric wakefield accelerators have shown great promise toward high-gradient acceleration. We investigate the performances of a possible experiment under consideration at the FLASH facility in DESY to explore wakefield acceleration with an enhanced transformer ratio. The experiment capitalizes on a unique pulse shaping capability recently demonstrated at this facility. In addition, the facility incorporates a superconducting linear accelerator that could generate bunch trains with closely spaced bunches thereby opening the exploration of potential dynamical effects in dielectric wakefield accelerators.
Book Synopsis Possibility for Ultra-bright Electron Beam Acceleration in Dielectric Wakefield Accelerators by :
Download or read book Possibility for Ultra-bright Electron Beam Acceleration in Dielectric Wakefield Accelerators written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Theory of the Dielectric Wakefield Accelerator by :
Download or read book Theory of the Dielectric Wakefield Accelerator written by and published by . This book was released on 1990 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: The general theory for all angular modes m of the dielectric wakefield accelerator is reformulated. The expressions for the accelerating electric fields and transverse wake forces are written in terms of matrices, the zeros of one of which determine the excitation frequencies of the dielectric structure. In this scheme it is possible to obtain a maximum accelerating gradient of 2.0 megavolts per meter per nanoCoulomb of driver beam charge, for a driver beam of 0.7 millimeters rms bunch length. 29 refs., 5 figs.
Book Synopsis Observation of Acceleration and Deceleration in Gigaelectron-volt-per-metre Gradient Dielectric Wakefield Accelerators by :
Download or read book Observation of Acceleration and Deceleration in Gigaelectron-volt-per-metre Gradient Dielectric Wakefield Accelerators written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: There is urgent need to develop new acceleration techniques capable of exceeding gigaelectron-volt-per-metre (GeV m-1) gradients in order to enable future generations of both light sources and high-energy physics experiments. To address this need, short wavelength accelerators based on wakefields, where an intense relativistic electron beam radiates the demanded fields directly into the accelerator structure or medium, are currently under intense investigation. One such wakefield based accelerator, the dielectric wakefield accelerator, uses a dielectric lined-waveguide to support a wakefield used for acceleration. Here we show gradients of 1.347±0.020 GeV m-1 using a dielectric wakefield accelerator of 15 cm length, with sub-millimetre transverse aperture, by measuring changes of the kinetic state of relativistic electron beams. We follow this measurement by demonstrating accelerating gradients of 320±17 MeV m-1. As a result, both measurements improve on previous measurements by and order of magnitude and show promise for dielectric wakefield accelerators as sources of high-energy electrons.
Book Synopsis Coherent Multimoded Dielectric Wakefield Accelerators by :
Download or read book Coherent Multimoded Dielectric Wakefield Accelerators written by and published by . This book was released on 1998 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: There has recently been a study of the potential uses of multimode dielectric structures for wakefield acceleration [1]. This technique is based on adjusting the wakefield modes of the structure to constructively interfere at certain delays with respect to the drive bunch, thus providing an accelerating gradient enhancement over single mode devices. In this report we examine and attempt to clarify the issues raised by this work in the light of the present state of the art in wakefield acceleration.
Book Synopsis Dielectric Wakefield Accelerator to Drive the Future FEL Light Source by :
Download or read book Dielectric Wakefield Accelerator to Drive the Future FEL Light Source written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: X-ray free-electron lasers (FELs) are expensive instruments and a large part of the cost of the entire facility is driven by the accelerator. Using a high-energy gain dielectric wake-field accelerator (DWA) instead of the conventional accelerator may provide a significant cost saving and reduction of the facility size. In this article, we investigate using a collinear dielectric wakefield accelerator to provide a high repetition rate, high current, high energy beam to drive a future FEL x-ray light source. As an initial case study, a ≈100 MV/m loaded gradient, 850 GHz quartz dielectric based 2-stage, wakefield accelerator is proposed to generate a main electron beam of 8 GeV, 50 pC/bunch, ≈1.2 kA of peak current, 10 x 10 kHz (10 beamlines) in just 100 meters with the fill factor and beam loading considered. This scheme provides 10 parallel main beams with one 100 kHz drive beam. A drive-to-main beam efficiency ≈38.5% can be achieved with an advanced transformer ratio enhancement technique. rf power dissipation in the structure is only 5 W/cm2 in the high repetition rate, high gradient operation mode, which is in the range of advanced water cooling capability. Details of study presented in the article include the overall layout, the transform ratio enhancement scheme used to increase the drive to main beam efficiency, main wakefield linac design, cooling of the structure, etc.
Book Synopsis High Gradient Dielectric Wakefield Device Measurements at the Argonne Wakefield Accelerator by :
Download or read book High Gradient Dielectric Wakefield Device Measurements at the Argonne Wakefield Accelerator written by and published by . This book was released on 1997 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Argonne Wakefield Accelerator (AWA) is a facility designed to investigate high gradient wakefield acceleration techniques. Wakefields are excited using a drive beam produced by a 14 MeV high current photoinjector-based linac. A second photocathode gun generates a 4 MeV witness beam which is used as a probe of the wakefields in the device under test. The delay of the witness bunch with respect to the drive bunch can be continuously varied from -100 ps to>1 ns. The drive and witness bunches propagate along collinear or parallel trajectories through the test section. A dipole spectrometer is then used to measure the energy change of the witness beam. The complete wakefield measurement system has been commissioned and wakefield experiments using dielectric structures are underway. Initial experiments have focused on collinear wakefield device geometries where the drive and witness bunches traverse the same structure. For attaining very high gradients we will construct and study step-up transformer structures in which the rf pulse generated by the drive beam is compressed transversely and longitudinally.
Book Synopsis Suppressing Parasitic Effects in a Long Dielectric Wakefield Accelerator by :
Download or read book Suppressing Parasitic Effects in a Long Dielectric Wakefield Accelerator written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Full-scale 2D and 3D Simulations of Electron Beam Acceleration for the LANL Dielectric Wakefield Accelerator Experiment by :
Download or read book Full-scale 2D and 3D Simulations of Electron Beam Acceleration for the LANL Dielectric Wakefield Accelerator Experiment written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
