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 Annular Beam driven High gradient Accelerators written by and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: During the past several years there has been an increasing interest in using wakefield acceleration techniques as a means for achieving TeV energies with the next generation of linear colliders. The principal design goals for a wakefield accelerator that is to be sued in this context are high accelerating gradients and large transformer ratios. Fundamentally any slow wave structure can function as a wakefield accelerator, and several interesting concepts have been proposed. In this paper we consider for the slow wave structure a dielectrically loaded waveguide. The Dielectric Wakefield Accelerator is a very simple device. The geometry consists of a gapless cavity filled with a dielectric. The dielectric may fill all or just part of the cavity. Here we investigate driving the system with an intense annular beam, so the dielectric is separated from the wall by a vacuum region in which this beam is propagated. The primary advantage of driving with an annular beam is that larger currents can be achieved, and thus larger accelerating gradients can be generated. The drive beam is stabilized by a strong, axial magnetic field. The wall is coated with a dielectric liner to provide for better coupling. A small hole is drilled in the center of the dielectric to allow for the passage of a low current, witness beam.
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.
Download or read book Tailored Electron Bunches with Smooth Current Profiles for Enhanced Transformer Ratios in Beam driven Acceleration written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Collinear high-gradient O(GV/m) beam-driven wakefield methods for charged-particle acceleration could be critical to the realization of compact, cost-efficient, accelerators, e.g., in support of TeV-scale lepton colliders or multiple-user free-electron laser facilities. To make these options viable, the high accelerating fields need to be complemented with large transformer ratios>2, a parameter characterizing the efficiency of the energy transfer between a wakefield-exciting "drive" bunch to an accelerated "witness" bunch. While several potential current distributions have been discussed, their practical realization appears challenging due to their often discontinuous nature. In this paper we propose several alternative continuously differentiable (smooth) current profiles which support enhanced transformer ratios. We especially demonstrate that one of the devised shapes can be implemented in a photo-emission electron source by properly shaping the photocathode-laser pulse. We finally discuss a possible superconducting linear-accelerator concept that could produce shaped drive bunches at high-repetition rates to drive a dielectric-wakefield accelerator with accelerating fields on the order of ~60 MV/m and a transformer ratio ~5 consistent with a recently proposed multiuser free-electron laser facility.
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.
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.
Download or read book High Energy Accelerators Heacc 92 Proceedings Of The Xv International Conference In 2 Volumes written by J Rossbach and published by World Scientific. This book was released on 1993-02-10 with total page 1288 pages. Available in PDF, EPUB and Kindle. Book excerpt: The High Energy Accelerator Conference has always been the monitor of the state of the art and the new trends in planning, construction and operation of large particle accelerators. It is held every three years. The 1992 conference is devoted to High Energy Hadron Accelerators and Colliders, Linear Colliders, e⁺e⁻ Storage Rings and related Technologies for these machines. In addition to status reports and contributed papers, the program features twelve survey talks which include summaries of individual poster papers.
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.
Download or read book Reviews Of Accelerator Science And Technology Volume 9 Technology And Applications Of Advanced Accelerator Concepts written by Alexander Wu Chao and published by World Scientific. This book was released on 2017-02-20 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since its invention in the 1920s, particle accelerators have made tremendous progress in accelerator science, technology and applications. However, the fundamental acceleration principle, namely, to apply an external radiofrequency (RF) electric field to accelerate charged particles, remains unchanged. As this method (either room temperature RF or superconducting RF) is approaching its intrinsic limitation in acceleration gradient (measured in MeV/m), it becomes apparent that new methods with much higher acceleration gradient (measured in GeV/m) must be found for future very high energy accelerators as well as future compact (table-top or room-size) accelerators. This volume introduces a number of advanced accelerator concepts (AAC) — their principles, technologies and potential applications. For the time being, none of them stands out as a definitive direction in which to go. But these novel ideas are in hot pursuit and look promising. Furthermore, some AAC requires a high power laser system. This has the implication of bringing two different communities — accelerator and laser — to join forces and work together. It will have profound impact on the future of our field.Also included are two special articles, one on 'Particle Accelerators in China' which gives a comprehensive overview of the rapidly growing accelerator community in China. The other features the person-of-the-issue who was well-known nuclear physicist Jerome Lewis Duggan, a pioneer and founder of a huge community of industrial and medical accelerators in the US.
Download or read book European Particle Accelerator Conference Epac 94 In 3 Volumes written by Christine Petit-jean-genaz and published by World Scientific. This book was released on 1994-11-26 with total page 2968 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings aim to provide a comprehensive overview of research, technology and applications in the field of accelerators. Contributions from the entire field of accelerators are presented, including low and high energy machines, and medical and industrial accelerators.
Download or read book Advanced Accelerator Concepts Lake Arrowhead CA 1989 written by Chan Joshi and published by Springer. This book was released on 1989 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt: Invited presentations and contributed papers from a January 1989 conference in Lake Arrowhead, California. Addresses plasma-based accelerator concepts and the use of plasmas in future high-energy accelerators, wake-field devices, radio and optical frequency acceleration and sources, high brightness
Download or read book Multi stage Wake field Accelerator written by and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper we propose a multi-stage wake field acceleration scheme to overcome the low transformer ratio problem and still provide high accelerating gradients. The idea is very simple. We use a train of several electron bunches from a linear accelerator (main linac) with well defined separations between the bunches (tens of ns) to drive wake field devices. Here we have made the assumption that the wake field devices are available, whether plasma, iris-loaded metallic or dielectric wake field structures. 10 refs.
Download or read book EPAC 90 written by P. Marin and published by Atlantica Séguier Frontières. This book was released on 1990 with total page 1054 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1990 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
