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 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 Ultra High Accelerating Gradients in Radio Frequency Cryogenic Copper Structures written by Alexander Cahill and published by . This book was released on 2017 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt: Normal conducting radio-frequency (rf) particle accelerators have many applications, including colliders for high energy physics, high-intensity synchrotron light sources, non-destructive testing for security, and medical radiation therapy. In these applications, the accelerating gradient is an important parameter. Specifically for high energy physics, increasing the accelerating gradient extends the potential energy reach and is viewed as a way to mitigate their considerable cost. Furthermore, a gradient increase will enable for more compact and thus accessible free electron lasers (FELs). The major factor limiting larger accelerating gradients is vacuum rf breakdown. Basic physics of this phenomenon has been extensively studied over the last few decades. During which, the occurrence of rf breakdowns was shown to be probabilistic, and can be characterized by a breakdown rate. The current consensus is that vacuum rf breakdowns are caused by movements of crystal defects induced by periodic mechanical stress. The stress may be caused by pulsed surface heating and large electric fields. A compelling piece of evidence that supports this hypothesis is that accelerating structures constructed from harder materials exhibit larger accelerating gradients for similar breakdown rates. One possible method to increase sustained electric fields in copper cavities is to cool them to temperatures below 77~K, where the rf surface resistance and coefficient of thermal expansion decrease, while the yield strength (which correlates with hardness) and thermal conductivity increase. These changes in material properties at low temperature increases metal hardness and decreases the mechanical stress from exposure to rf electromagnetic fields. To test the validity of the improvement in breakdown rate, experiments were conducted with cryogenic accelerating cavities in the Accelerator Structure Test Area (ASTA) at SLAC National Accelerator Laboratory. A short 11.4~GHz standing wave accelerating structure was conditioned to an accelerating gradient of 250~MV/m at 45~K with $10^8$ rf pulses. At gradients greater than 150~MV/m I observed a degradation in the intrinsic quality factor of the cavity, $Q_0$. I developed a model for the change in $Q_0$ using measured field emission currents and rf signals. I found that the $Q_0$ degradation is consistent with the rf power being absorbed by strong field emission currents accelerated inside the cavity. I measured rf breakdown rates for 45~K and found $2*10^{-4}/pulse/meter$ when accounting for any change in $Q_0$. These are the largest accelerating gradients for a structure with similar breakdown rates. The final chapter presents the design of an rf photoinjector electron source that uses the cryogenic normal conducting accelerator technology: the TOPGUN. With this cryogenic rf photoinjector, the beam brightness will increase by over an order of a magnitude when compared to the current photoinjector for the Linac Coherent Light Source (LCLS). When using the TOPGUN as the source for an X-ray Free Electron Laser, the higher brightness would allow for a decrease in the required length of the LCLS undulator by more than a factor of two.
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 Progress Report on High gradient RF Studies in Copper Accelerator Structures written by and published by . This book was released on 1990 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper is a progress report on studies carried out at the Stanford Linear Accelerator Center to understand the behavior of copper accelerator structures under extremely high RF fields. Such structures are being designed for future electron-positron linear colliders. Recent studies include field emission and breakdown experiments with an S-band slotted-disk structure, a single demountable S-band cavity and a short X-band structure which has not yet been tested. The demountable cavity was built specifically to examine the effects of copper quality, surface conditioning, gaseous exposures, and surface damage. Results to date and recent theoretical conjectures are discussed.
Download or read book PROGRESS REPORT ON HIGH GRADIENT RF STUDIES IN COPPER ACCELERATOR STRUCTURES written by G.A. LOEW and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Principles of Environmental Physics written by John Monteith and published by Butterworth-Heinemann. This book was released on 1990-02-15 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thoroughly revised and up-dated edition of a highly successful textbook.
Download or read book RF Linear Accelerators written by Thomas P. Wangler and published by John Wiley & Sons. This book was released on 2008-03-03 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dieses einschlägige Lehrbuch, entwickelt auf der Grundlage der Ausbildung an der US Particle Accelerator School, schließt eine Lücke in der verfügbaren Literatur zum Thema Hochfrequenz-Linearbeschleuniger, kurz RF-Linac. Nach einer Erläuterung der naturwissenschaftlichen Grundlagen und der neuesten technologischen Eckdaten stellt diese zweite Auflage neueste RF-Linacs, spezialisierte Systeme, Systeme mit Supraleitern und verschiedene Spezialverfahren vor. Übungsaufgaben an den Kapitelenden erleichtern das Einprägen und das Nacharbeiten von Vorlesungen.
Download or read book Microstructural Characterization of Materials written by David Brandon and published by John Wiley & Sons. This book was released on 2013-03-21 with total page 517 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microstructural characterization is usually achieved by allowing some form of probe to interact with a carefully prepared specimen. The most commonly used probes are visible light, X-ray radiation, a high-energy electron beam, or a sharp, flexible needle. These four types of probe form the basis for optical microscopy, X-ray diffraction, electron microscopy, and scanning probe microscopy. Microstructural Characterization of Materials, 2nd Edition is an introduction to the expertise involved in assessing the microstructure of engineering materials and to the experimental methods used for this purpose. Similar to the first edition, this 2nd edition explores the methodology of materials characterization under the three headings of crystal structure, microstructural morphology, and microanalysis. The principal methods of characterization, including diffraction analysis, optical microscopy, electron microscopy, and chemical microanalytical techniques are treated both qualitatively and quantitatively. An additional chapter has been added to the new edition to cover surface probe microscopy, and there are new sections on digital image recording and analysis, orientation imaging microscopy, focused ion-beam instruments, atom-probe microscopy, and 3-D image reconstruction. As well as being fully updated, this second edition also includes revised and expanded examples and exercises, with a solutions manual available at http://develop.wiley.co.uk/microstructural2e/ Microstructural Characterization of Materials, 2nd Edition will appeal to senior undergraduate and graduate students of material science, materials engineering, and materials chemistry, as well as to qualified engineers and more advanced researchers, who will find the book a useful and comprehensive general reference source.
Download or read book Characterization integration and reliability of HfO2 and LaLuO3 high metal gate stacks for CMOS applications written by Alexander Nichau and published by Forschungszentrum Jülich. This book was released on 2014-04-03 with total page 199 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Friction Stir Welding written by Daniela Lohwasser and published by Elsevier. This book was released on 2009-12-18 with total page 437 pages. Available in PDF, EPUB and Kindle. Book excerpt: Friction stir welding (FSW) is a highly important and recently developed joining technology that produces a solid phase bond. It uses a rotating tool to generate frictional heat that causes material of the components to be welded to soften without reaching the melting point and allows the tool to move along the weld line. Plasticized material is transferred from the leading edge to trailing edge of the tool probe, leaving a solid phase bond between the two parts. Friction stir welding: from basics to applications reviews the fundamentals of the process and how it is used in industrial applications.Part one discusses general issues with chapters on topics such as basic process overview, material deformation and joint formation in friction stir welding, inspection and quality control and friction stir welding equipment requirements and machinery descriptions as well as industrial applications of friction stir welding. A chapter giving an outlook on the future of friction stir welding is included in Part one. Part two reviews the variables in friction stir welding including residual stresses in friction stir welding, effects and defects of friction stir welds, modelling thermal properties in friction stir welding and metallurgy and weld performance.With its distinguished editors and international team of contributors, Friction stir welding: from basics to applications is a standard reference for mechanical, welding and materials engineers in the aerospace, automotive, railway, shipbuilding, nuclear and other metal fabrication industries, particularly those that use aluminium alloys. Provides essential information on topics such as basic process overview, materials deformation and joint formation in friction stir welding Inspection and quality control and friction stir welding equipment requirements are discussed as well as industrial applications of friction stir welding Reviews the variables involved in friction stir welding including residual stresses, effects and defects of friction stir welds, modelling thermal properties, metallurgy and weld performance
Download or read book Extractive Metallurgy of Niobium written by A.K. Suri and published by Routledge. This book was released on 2017-11-13 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: The growth and development witnessed today in modern science, engineering, and technology owes a heavy debt to the rare, refractory, and reactive metals group, of which niobium is a member. Extractive Metallurgy of Niobium presents a vivid account of the metal through its comprehensive discussions of properties and applications, resources and resource processing, chemical processing and compound preparation, metal extraction, and refining and consolidation. Typical flow sheets adopted in some leading niobium-producing countries for the beneficiation of various niobium sources are presented, and various chemical processes for producing pure forms of niobium intermediates such as chloride, fluoride, and oxide are discussed. The book also explains how to liberate the metal from its intermediates and describes the physico-chemical principles involved. It is an excellent reference for chemical metallurgists, hydrometallurgists, extraction and process metallurgists, and minerals processors. It is also valuable to a wide variety of scientists, engineers, technologists, and students interested in the topic.
Download or read book Mechanical Metallurgy written by George Ellwood Dieter and published by McGraw-Hill Companies. This book was released on 1988-01-01 with total page 751 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Status of Accelerator Driven Systems Research and Technology Development written by International Atomic Energy Agency and published by IAEA Tecdoc. This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the greatest challenges for nuclear energy is how to properly manage the highly radioactive waste generated during irradiation in nuclear reactors. Accelerator Driven Systems (ADSs) may offer new prospects and advantages for the transmutation of such high level nuclear waste. ADS or accelerator driven transmutation of waste (ATW) consists of a high power proton accelerator, a heavy metal spallation target that produces neutrons when bombarded by the high power beam, and a sub-critical core that is neutronically coupled to the spallation target. This publication provides a comprehensive state of the art of the ADS technology by representing the different ADS concepts proposed worldwide in the last 15 years, as well as the related R&D activities and demonstration initiatives carried out at national international level.
Download or read book Active Protective Coatings written by Anthony E. Hughes and published by Springer. This book was released on 2016-03-01 with total page 429 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers a broad range of materials science that has been brought to bear on providing solutions to the challenges of developing self-healing and protective coatings for a range of metals. The book has a strong emphasis on characterisation techniques, particularly new techniques that are beginning to be used in the coatings area. It features many contributions written by experts from various industrial sectors which examine the needs of the sectors and the state of the art. The development of self-healing and protective coatings has been an expanding field in recent years and applies a lot of new knowledge gained from other fields as well as other areas of materials science to the development of coatings. It has borrowed from fields such as the food and pharmaceutical industries who have used, polymer techniques, sol-gel science and colloidosome technology for a range encapsulation techniques. It has also borrowed from fields like hydrogen storage such as from the development of hierarchical and other materials based on organic templating as “nanocontainers” for the delivery of inhibitors. In materials science, recent developments in high throughput and other characterisation techniques, such as those available from synchrotrons, are being increasing used for novel characterisation – one only needs to look at the application of these techniques in self healing polymers to gauge wealth of new information that has been gained from these techniques. This work is largely driven by the need to replace environmental pollutants and hazardous chemicals that represent risk to humans such as chromate inhibitors which are still used in some applications.
Download or read book Climate Intervention written by National Research Council and published by National Academies Press. This book was released on 2015-06-23 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: The growing problem of changing environmental conditions caused by climate destabilization is well recognized as one of the defining issues of our time. The root problem is greenhouse gas emissions, and the fundamental solution is curbing those emissions. Climate geoengineering has often been considered to be a "last-ditch" response to climate change, to be used only if climate change damage should produce extreme hardship. Although the likelihood of eventually needing to resort to these efforts grows with every year of inaction on emissions control, there is a lack of information on these ways of potentially intervening in the climate system. As one of a two-book report, this volume of Climate Intervention discusses albedo modification - changing the fraction of incoming solar radiation that reaches the surface. This approach would deliberately modify the energy budget of Earth to produce a cooling designed to compensate for some of the effects of warming associated with greenhouse gas increases. The prospect of large-scale albedo modification raises political and governance issues at national and global levels, as well as ethical concerns. Climate Intervention: Reflecting Sunlight to Cool Earth discusses some of the social, political, and legal issues surrounding these proposed techniques. It is far easier to modify Earth's albedo than to determine whether it should be done or what the consequences might be of such an action. One serious concern is that such an action could be unilaterally undertaken by a small nation or smaller entity for its own benefit without international sanction and regardless of international consequences. Transparency in discussing this subject is critical. In the spirit of that transparency, Climate Intervention: Reflecting Sunlight to Cool Earth was based on peer-reviewed literature and the judgments of the authoring committee; no new research was done as part of this study and all data and information used are from entirely open sources. By helping to bring light to this topic area, this book will help leaders to be far more knowledgeable about the consequences of albedo modification approaches before they face a decision whether or not to use them.
Download or read book Modern Physics written by Paul Allen Tipler and published by Worth Pub. This book was released on 1978 with total page 502 pages. Available in PDF, EPUB and Kindle. Book excerpt: For the intermediate-level course, the Fifth Edition of this widely used text takes modern physics textbooks to a higher level. With a flexible approach to accommodate the various ways of teaching the course (both one- and two-term tracks are easily covered), the authors recognize the audience and its need for updated coverage, mathematical rigor, and features to build and support student understanding. Continued are the superb explanatory style, the up-to-date topical coverage, and the Web enhancements that gained earlier editions worldwide recognition. Enhancements include a streamlined approach to nuclear physics, thoroughly revised and updated coverage on particle physics and astrophysics, and a review of the essential Classical Concepts important to students studying Modern Physics.
