Download or read book RF Processing of X Band Accelerator Structures at the NLCTA written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: During the initial phase of operation, the linacs of the Next Linear Collider (NLC) will contain roughly 5,000 X-Band accelerator structures that will accelerate beams of electrons and positrons to 250 GeV. These structures will nominally operate at an unloaded gradient of 72 MV/m. As part of the NLC R and D program, several prototype structures have been built and operated at the Next Linear Collider Test Accelerator (NLCTA) at SLAC. Here, the effect of high gradient operation on the structure performance has been studied. Significant progress was made during the past year after the NLCTA power sources were upgraded to reliably produce the required NLC power levels and beyond. This paper describes the structures, the processing methodology and the observed effects of high gradient operation.
Download or read book Processing Studies of X Band Accelerator Structures at the NLCTA written by and published by . This book was released on 2001 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: RF processing studies of 1.8-m X-band (11.4 GHz) traveling wave structures at the Next Linear Collider Test Accelerator (NLCTA) have revealed breakdown-related damage at gradients lower than expected from earlier tests with standing wave and shorter, lower group velocity traveling wave structures. To understand this difference, a series of structures with different group velocities and lengths are being processed. In parallel, efforts are being made to improve processing procedures and to reduce structure contaminants and absorbed gases. This paper presents results from these studies.
Download or read book Investigations on rf breakdown phenomenon in high gradient accelerating structures written by Jiahang Shao and published by Springer. This book was released on 2018-01-19 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book mainly focuses on the experimental research of rf breakdown and field emission with novel methods, including triggering rf breakdown with high intensity laser and pin-shaped cathodes as well as locating field emitters with a high resolution in-situ imaging system. With these methods, this book has analyzed the power flow between cells during rf breakdown, observed the evolution of field emission during rf conditioning and the dependence of field emission on stored energy, and studied the field emitter distribution and origination. The research findings greatly expand the understanding of rf breakdown and field emission, which will in turn benefit future study into electron sources, particle accelerators, and high gradient rf devices in general.
Download or read book High Energy Density and High Power RF written by David K. Abe and published by Springer Science & Business Media. This book was released on 2006-01-04 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the seventh in a series of international workshops on high-power and high-energy density microwave devices for accelerator, plasma physics, and defense applications. The scope of this workshop included accelerators for high energy physics, plasma heating and current drive in controlled thermonuclear fusion research, radar and directed energy/high power microwave systems, THz sources and technologies, and advanced 2D/3D computational tool development.
Download or read book X band Dielectric Loaded RF Driven Accelerator Structures written by Peng Zou and published by . This book was released on 2001 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Energy Density and High Power RF written by Steven H. Gold and published by American Institute of Physics. This book was released on 2003-12-04 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the sixth in a series of international workshops on high-power and high-energy density microwave devices for accelerator, plasma physics, and defense applications. Past workshops were held in Dubna, Montauk, Hayama, Pajaro Dunes, and Snowbird. The theme is research and development of techniques to increase microwave energy density and peak power in active and passive microwave devices and components ranging from L-band to W-band. The scope of this workshop has now been broadened to include radar and high power microwave (HPM) systems, space exploration, neutron sources, and even plasma heating and current drive in controlled thermonuclear fusion research.
Download or read book High Energy Density and High Power RF written by and published by . This book was released on 2001 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Demonstration of an RF System for the X Band Linear Collider written by and published by . This book was released on 2004 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Designs for a future X-band linear collider (NLC/GLC) require an rf unit that can produce 450 MW to feed eight 60 cm accelerator structures. The implementation of this rf unit is envisioned to include a dual-moded SLED-II pulse compression system, with a gain of approximately three at a compression ratio of four, followed by an overmoded transmission and distribution system. We describe the tunnel layout plan for these rf systems. The design, construction, and operation of a prototype system are a focus of the 8-Pack project at SLAC. In its initial phase last fall, powered by four 50 MW X-band klystrons sharing a common 400 kV solid-state modulator, the SLED-II system delivered to a set of loads 400 ns pulses of up to 580 MW. In the next phase, this power will be delivered to the NLCTA beamline and distributed between several structures, through which a bunch train will be accelerated. We describe the layout of this system and the functionality of various overmoded, high-power components which comprise it. We also present data on the cold testing, processing and initial operation of the system, which is setting high-power records in pulsed rf.
Download or read book Surface Analysis of OFE Copper X Band Accelerating Structures and Possible Correlation to RF Breakdown Events written by S. Harvey and published by . This book was released on 2003 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: X-band accelerator structures meeting the Next Linear Collider (NLC) design requirements have been found to suffer vacuum surface damage caused by radio frequency (RF) breakdown, when processed to high electric-field gradients. Improved understanding of these breakdown events is desirable for the development of structure designs, fabrication procedures, and processing techniques that minimize structure damage. RF reflected wave analysis and acoustic sensor pickup have provided breakdowns localization in RF structures. Particle contaminations found following clean autopsy of four RF-processed travelling wave structures, have been catalogued and analyzed. Their influence on RF breakdown, as well as that of several other material-based properties, will be discussed.
Download or read book High Gradient Experiments on NLCTA Accelerator Structures written by and published by . This book was released on 1996 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper presents new results of high-gradient studies performed on a 1.8 m traveling-wave accelerator section with detuned high-order deflecting modes. This structure was designed initially for studies of detuned structures and will be installed in the Next Linear Collider Test Accelerator (NLCTA). The paper describes the test set-up in the Accelerator Structure Test Area (ASTA) including electron gun, prebuncher, pre-accelerator, spectrometer, Faraday cups, 200 MW SLED-II power compression system, Magic-T type phase shifters and attenuators. Rf processing, detailed dark current analysis, radiation problems, and beam acceleration measurements are discussed.
Download or read book Studies of Breakdown in High Gradient X Band Accelerator Structures Using Acoustic Emission written by and published by . This book was released on 2002 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: X-band accelerator structures meeting the Next Linear Collider (NLC) design requirements have been found to suffer damage due to RF breakdown when processed to high gradients. Improved understanding of these breakdown events is desirable for the development of structure designs, fabrication procedures, and processing techniques that minimize structure damage [1]. Acoustic emission sensors attached to an accelerator structure can detect both nominal and breakdown RF pulses [2]. Using an array of acoustic sensors, we have been able to pinpoint both the cell and azimuth location of individual breakdown events. This allows studies of breakdown time and position sequences so that underlying causes can be determined. The technique provided a significant advance in studies of breakdown in the structure input coupler. In this paper we present acoustic emission sensor data and analysis from the breakdown studies in several x-band accelerator structures.
Download or read book The Division of Particles and Fields of the American Physical Society DPF 2000 written by American Physical Society. Division of Particles and Fields. Meeting and published by . This book was released on 2001 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Gradient Test of a Clamped Molybdenum Iris X Band Accelerator Structure at NLCTA written by S. Doebert and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Inspired by the very high gradients (150-195 MV/m) achieved at CERN in 30 GHz accelerator structures made with tungsten and molybdenum irises and operated with short (16 ns) rf pulses [1], an X-band (11.4 GHz) version of this structure design was built at CERN and tested at SLAC. The goals of this experiment were to provide frequency scaling data on high gradient phenomena at similar pulse lengths, and to measure the structure performance at the longer pulse lengths available at SLAC (the CLIC test facility, CTF II, could provide only 16 ns pulses for high power operation and 32 ns pulses for medium power operation). Earlier high gradient tests of 21 GHz to 39 GHz standing-wave, single cells, indicated no significant frequency dependence of the maximum obtainable surface field [2]. The X-band scaling test would check if this was true for travelling-wave, multi-cell structures as well. For the experiment, the CLIC group at CERN built a 30 cell accelerating structure that consisted of copper cells and molybdenum irises that were clamped together. The structure was mounted in a vacuum tank and installed in the Next Linear Collider Test Accelerator (NLCTA) beam line at SLAC where it was operated at high power for more than 700 hours.
Download or read book Impact of Surface Preparation on RF Breakdown Performance in NLCTA Accelerating Structures LCC 0081 written by R. Kirby and published by . This book was released on 2003 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: In an effort to locate the cause(s) of high electric-field breakdown in X-band accelerating structures, a systematic study was begun on characterizing the effect of etching time on surface roughness, using OFE copper witness coupons made of the same material that was used for structures and machined in identical fashion to those structures. It was found that the minimum surface roughness corresponded to 45 and 5 second etching times on conventional and single-crystal, diamond machined surfaces, respectively. These values are essentially identical, within error, to the times used to obtain the best breakdown results for either type of machined structure.
Download or read book High Energy Density and High Power RF written by Bruce E. Carlsten and published by AIP Conference Proceedings / A. This book was released on 2002-08-14 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the fifth in a series of workshops focused on high-power RF sources, originally for accelerator applications, but now including other applications as well. These proceedings report on recent progress in high-power klystrons, traveling-wave tubes, other linear beam tubes, fast-wave devices, and supporting technologies.
Download or read book Localization of RF Breakdown in Copper RF Structure by the Use of Acoustic Sensors written by F. Le Pimpec and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: X-band accelerator structures meeting the Next Linear Collider (NLC) design requirements have been found to suffer damage due to Radio Frequency (RF) breakdown when processed to high gradients. Improved understanding of these breakdown events is desirable for the development of structure designs, fabrication procedures, and processing techniques that minimize structure damage. Acoustic sensors attached to an accelerator structure can detect both normal and breakdown RF pulses. Using an array of acoustic sensors, we have been able to pinpoint both the cell and azimuth location of individual breakdown events. This allows studies of breakdown in time and in space, so that underlying causes can be determined. This technique provided a significant understanding of breakdown in the structure input coupler.
Download or read book Advances in X Band TW Accelerator Structures Operating in the 100 MV M Regime written by and published by . This book was released on 2012 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: A CERN-SLAC-KEK collaboration on high gradient X-band accelerator structure development for CLIC has been ongoing for three years. The major outcome has been the demonstration of stable 100 MV/m gradient operation of a number of CLIC prototype structures. These structures were fabricated using the technology developed from 1994 to 2004 for the GLC/NLC linear collider initiative. One of the goals has been to refine the essential parameters and fabrication procedures needed to realize such a high gradient routinely. Another goal has been to develop structures with stronger dipole mode damping than those for GLC/NLC. The latter requires that the surface temperature rise during the pulse be higher, which may increase the breakdown rate. One structure with heavy damping has been RF processed and another is nearly finished. The breakdown rates of these structures were found to be higher by two orders of magnitude compared to those with equivalent acceleration mode parameters but without the damping features. This paper presents these results together with some of the earlier results from non-damped structures.
