Download or read book Development of Superconducting RF Sample Host Cavities and Study of Pit induced Cavity Quench written by Yi Xie and published by . This book was released on 2013 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: Superconducting rf (SRF) cavities made of niobium are now approaching their theoretical superheating field limit. Alternative materials such as Nb3 Sn and MgB2 are predicted to have significant higher fields and are very interesting for next generation srf cavities. A high field and high sensitivity sample host cavity will be an ideal tool for studying various field-dependent loss phenomena and to explore the ultimate performance of these new types of rf superconductors. In this thesis, I will present my developments of two TE-type sample host niobium cavity systems which recently have reached among the highest magnetic field ever achieved (~ 60 mT) on the sample surface with n[OHM SIGN] sensitivity in rf surface resistance. The rf design, fabrication, surface treatments, input coupler development and rf testing results both with baseline niobium and with a Nb3 Sn sample plate will be presented in detail. Methods of improving sample surface magnetic field up to 100 mT will be presented. Surface defects such as pits have been identified as some of the main sources of limitations of srf cavity performance. I have made a single cell cavity with 30 artificial pits in the high magnetic field region to gain new insight in how pits limit the cavity performance. The test of the pit cavity showed clear evidence that the edges of two of the largest radius pits transitioned into the normal conducting state at field just below the quench field of the cavity, and that the quench was indeed induced by these two pits. The pit geometrical informa- tion measured by laser confocal microscopy combined with a numerical finite element ring-type defect model will be compared with temperature mapping results. Insights about quench and non-linear rf resistances will be presented.
Download or read book New Results of Development on High Efficiency High Gradient Superconducting Rf Cavities written by and published by . This book was released on 2015 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report on the latest results of development on high-efficiency high-gradient superconducting radio frequency (SRF) cavities. Several 1-cell cavities made of large-grain niobium (Nb) were built, processed and tested. Two of these cavities are of the Low Surface Field (LSF) shape. Series of tests were carried out following controlled thermal cycling. Experiments toward zero-field cooling were carried out. The best experimentally achieved results are Eacc = 41 MV/m at Q0 = 6.5×1010 at 1.4 K by a 1-cell 1.3 GHz large-grain Nb TTF shape cavity and Eacc = 49 MV/m at Q0 = 1.5×1010 at 1.8 K by a 1-cell 1.5 GHz large-grain Nb CEBAF upgrade low-loss shape cavity.
Download or read book Investigation of Microscopic Materials Limitations of Superconducting RF Cavities written by and published by . This book was released on 2014 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: The high-field performance of SRF cavities is often limited by breakdown events below the intrinsic limiting surface fields of Nb, and there is abundant evidence that these breakdown events are localized in space inside the cavity. Also, there is a lack of detailed understanding of the causal links between surface treatments and ultimate RF performance at low temperatures. An understanding of these links would provide a clear roadmap for improvement of SRF cavity performance, and establish a cause-and-effect ‘RF materials science’ of Nb. We propose two specific microscopic approaches to addressing these issues. First is a spatially-resolved local microwave-microscope probe that operates at SRF frequencies and temperatures to discover the microscopic origins of breakdown, and produce quantitative measurements of RF critical fields of coatings and films. Second, RF Laser Scanning Microscopy (LSM) has allowed visualization of RF current flow and sources of nonlinear RF response in superconducting devices with micro-meter spatial resolution. The LSM will be used in conjunction with surface preparation and characterization techniques to create definitive links between physical and chemical processing steps and ultimate cryogenic microwave performance. We propose to develop RF laser scanning microscopy of small-sample Nb pieces to establish surface-processing / RF performance relations through measurement of RF current distributions on micron-length scales and low temperatures.
Download or read book Development of Ultra High Gradient and High Q sub 0 Superconducting Radio Frequency Cavities written by and published by . This book was released on 2013 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report on the recent progress at Jefferson Lab in developing ultra high gradient and high Q0 superconducting radio frequency (SRF) cavities for future SRF based machines. A new 1300 MHz 9-cell prototype cavity is being fabricated. This cavity has an optimized shape in terms of the ratio of the peak surface field (both magnetic and electric) to the acceleration gradient, hence the name low surface field (LSF) shape. The goal of the effort is to demonstrate an acceleration gradient of 50 MV/m with Q0 of 101° at 2 K in a 9-cell SRF cavity. Fine-grain niobium material is used. Conventional forming, machining and electron beam welding method are used for cavity fabrication. New techniques are adopted to ensure repeatable, accurate and inexpensive fabrication of components and the full assembly. The completed cavity is to be first mechanically polished to a mirror-finish, a newly acquired in-house capability at JLab, followed by the proven ILC-style processing recipe established already at JLab. In parallel, new single-cell cavities made from large-grain niobium material are made to further advance the cavity treatment and processing procedures, aiming for the demonstration of an acceleration gradient of 50 MV/m with Q0 of 2-101° at 2K.
Download or read book ELECTRON TUNNELING STUDIES OF MATERIALS FOR SUPERCONDUCTING RADIO FREQUENCY APPLICATIONS written by Eric Lechner and published by . This book was released on 2019 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radio frequency (RF) cavities are the foundational infrastructure which facilitates much of the fundamental research conducted in high energy particle physics. These RF cavities utilize their unique shape to produce resonant electromagnetic fields used to accelerate charged particles. Beside their core role in fundamental physics research, RF cavities have found application in other disciplines including material science, chemistry and biology which take advantage of their unique light sources. Industry has been keen on taking advantage of accelerator technology for a multitude of applications. Particle accelerators like the one found at Jefferson Lab's Continuous Electron Beam Accelerator Facility must produce stable beams of high energy particles which is an incredibly costly endeavor to pursue. With the gargantuan size of these facilities, the cost of high-quality beam production is a matter of great importance. The quest to find highly efficient RF cavities has resulted in the widespread use of superconducting radio frequency (SRF) cavities which are the most efficient resonators that exploit a superconductor's incredibly low AC surface resistance. While metals like Cu are up to the demanding job of RF cavity particle acceleration, their efficiency at transferring RF power to the particle beam is low when they are compared with SRF Nb cavities. Nb is the standard material for all SRF cavity technology particularly for its reproducibly low surface resistance, comparatively high transition temperature and thermodynamic critical field. Using superconducting Nb is not without its drawbacks. Keeping hundreds of Nb cavities in their superconducting state under extreme RF conditions is quite a daunting task. It requires the normal state not nucleate during operation. This is achieved by producing high-quality cavities with as few defects and impurities as possible while also keeping the cavities at low temperature, usually 2K. Again, due to the sheer scale of the facilities, hundred million-dollar cryogenic plants are required to handle the heat loads during SRF cavity operation. This means even small increases in maximum accelerating gradients or decrease in cavity surface resistance results in a sizably reduced operation cost. Considerable effort has been put forth to increase the efficiency of Nb cavities toward and even beyond the theoretical maximum accelerating gradients and quality factor for a clean superconductor. Recently, a new method to produce high quality factor cavities has emerged that involves nitrogen doping the cavity. The mechanism by which N doping causes the improvement is still not well understood, but the experimental research described in this dissertation shines some light into the mechanisms behind such a drastic improvement. These insights are universal for all superconductors and may prove useful for SRF cavities beyond Nb. With Nb approaching its fundamental limits, new materials are being proposed to increase the performance of future SRF cavities which MgB2 finds itself among. MgB2 is a two-band superconductor that possesses many properties that are very attractive for the next generation of SRF cavities. One of the most important properties is MgB2's comparatively large critical temperature which in part predicts it will have a lower surface resistance than Nb at higher operating temperatures. Such behavior of MgB2 may unlock the possibility of using cryocoolers instead of costly liquid helium plants for large scale industrial use. This dissertation starts with an introduction to superconductivity, its theory, and application to SRF cavities as well as the open questions that can be addressed in Nb and the next generation of SRF materials. A description of the experimental techniques of scanning tunneling microscopy, X-ray photoelectron spectroscopy, and atomic force microscopy is presented. Our experimental investigation into Nb SRF cavity cutouts starts with a discussion of the material's limitations for SRF applications with an emphasis on the proximity effect which arises at the surface of this material due to its myriad of naturally forming oxides. The results of our scanning tunneling microscopy measurements for typically prepared Nb and nitrogen doped Nb follows and comparisons are made which show that the surface oxides are fundamentally different between these samples likely resulting in the profound enhancement of the cavity's quality factor. Experimental investigation into the native oxide of hot spot nitrogen doped Nb shows a degraded oxide and superconducting properties as compared with the cold spot. The dissertation continues with a brief introduction to MgB2, followed by our scanning tunneling and electron tunneling insights into MgB2. The dissertation is concluded with a summary of our investigations and broader impact of our research on the SRF community.
Download or read book RF Superconductivity for Accelerators written by Hasan Padamsee and published by John Wiley & Sons. This book was released on 2008-02-26 with total page 548 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces some of the key ideas of this exciting field, using a pedagogic approach, and presents a comprehensive overview of the field. It is divided into four parts. The first part introduces the basic concepts of microwave cavities for particle acceleration. The second part is devoted to the observed behavior of superconducting cavities. In the third part,general issues connected with beam-cavity interaction and the related issues for the critical components are covered. The final part discusses applications of superconducting cavities to frontier accelerators of the future, drawing heavily on the examples that are in their most advanced stage. Each part of the book ends in a Problems section to illustrate and amplify text material as well as draw on example applications of superconducting cavities to existing and future accelerators.
Download or read book High Luminosity Large Hadron Collider HL LHC written by G.. Apollinari and published by . This book was released on 2017 with total page 516 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book World Congress on Superconductivity written by Calvin G. Burnham and published by World Scientific. This book was released on 1988 with total page 710 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of high temperature superconductors is one of the major technological discoveries of this century. The impact and interactions from the scientific, technical, business and political aspects will be presented.
Download or read book Superconductivity written by R.G. Sharma and published by Springer. This book was released on 2015-02-26 with total page 427 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the basics and applications of superconducting magnets. It explains the phenomenon of superconductivity, theories of superconductivity, type II superconductors and high-temperature cuprate superconductors. The main focus of the book is on the application to superconducting magnets to accelerators and fusion reactors and other applications of superconducting magnets. The thermal and electromagnetic stability criteria of the conductors and the present status of the fabrication techniques for future magnet applications are addressed. The book is based on the long experience of the author in studying superconducting materials, building magnets and numerous lectures delivered to scholars. A researcher and graduate student will enjoy reading the book to learn various aspects of magnet applications of superconductivity. The book provides the knowledge in the field of applied superconductivity in a comprehensive way.
Download or read book New Views of the Moon written by Bradley L. Jolliff and published by Walter de Gruyter GmbH & Co KG. This book was released on 2018-12-17 with total page 756 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 60 of Reviews in Mineralogy and Geochemistry assesses the current state of knowledge of lunar geoscience, given the data sets provided by missions of the 1990's, and lists remaining key questions as well as new ones for future exploration to address. It documents how a planet or moon other than the world on which we live can be studied and understood in light of integrated suites of specific kinds of information. The Moon is the only body other than Earth for which we have material samples of known geologic context for study. This volume seeks to show how the different kinds of information gained about the Moon relate to each other and also to learn from this experience, thus allowing more efficient planning for the exploration of other worlds.
Download or read book The Large Hadron Collider written by Lyndon R. Evans and published by EPFL Press. This book was released on 2009-01-01 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: Describes the technology and engineering of the Large Hadron collider (LHC), one of the greatest scientific marvels of this young 21st century. This book traces the feat of its construction, written by the head scientists involved, placed into the context of the scientific goals and principles.
Download or read book RF Superconductivity written by Hasan Padamsee and published by John Wiley & Sons. This book was released on 2009-03-30 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the second book to RF Superconducting, written by one of the leading experts. The book provides fast and up-to-date access to the latest advances in the key technology for future accelerators. Experts as well as newcomers to the field will benefit from the discussion of progress in the basic science, technology as well as recent and forthcoming applications. Researchers in accelerator physics will also find much that is relevant to their discipline.
Download or read book The Science and Technology of Superconductivity written by William David Gregory and published by Springer. This book was released on 1973-02 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the discovery of superconductivity in 1911 by H. Kamerlingh Onnes, of the order of half a billion dollars has been spent on research directed toward understanding and utiliz ing this phenomenon. This investment has gained us fundamental understanding in the form of a microscopic theory of superconduc tivity. Moreover, superconductivity has been transformed from a laboratory curiosity to the basis of some of the most sensitive and accurate measuring devices known, a whole host of other elec tronic devices, a soon-to-be new international standard for the volt, a prototype generation of superconducting motors and gener ators, and magnets producing the highest continuous magnetic fields yet produced by man. The promise of more efficient means of power transmission and mass transportation, a new generation of superconducting motors and generators, and computers and other electronic devices with superconducting circuit elements is all too clear. The realization of controlled thermonuclear fusion is perhaps totally dependent upon the creation of enormous magnetic fields over large volumes by some future generation of supercon ducting magnets. Nevertheless, whether or not the technological promise of superconductivity comes to full flower depends as much, and perhaps more, upon economic and political factors as it does upon new technological and scientific breakthroughs. The basic science of superconductivity and its technological implications were the subject of a short course on "The Science and Technology of Superconductivity" held at Georgetown University, Washington, D. C. , during 13-26 August 1971.
Download or read book Applied Superconductivity written by Paul Seidel and published by John Wiley & Sons. This book was released on 2015-03-23 with total page 1334 pages. Available in PDF, EPUB and Kindle. Book excerpt: This wide-ranging presentation of applied superconductivity, from fundamentals and materials right up to the details of many applications, is an essential reference for physicists and engineers in academic research as well as in industry. Readers looking for a comprehensive overview on basic effects related to superconductivity and superconducting materials will expand their knowledge and understanding of both low and high Tc superconductors with respect to their application. Technology, preparation and characterization are covered for bulk, single crystals, thins fi lms as well as electronic devices, wires and tapes. The main benefit of this work lies in its broad coverage of significant applications in magnets, power engineering, electronics, sensors and quantum metrology. The reader will find information on superconducting magnets for diverse applications like particle physics, fusion research, medicine, and biomagnetism as well as materials processing. SQUIDs and their usage in medicine or geophysics are thoroughly covered, as are superconducting radiation and particle detectors, aspects on superconductor digital electronics, leading readers to quantum computing and new devices.
Download or read book Bio Inspired Innovation and National Security written by National Defense University and published by NDU Press. This book was released on 2010-10 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite the vital importance of the emerging area of biotechnology and its role in defense planning and policymaking, no definitive book has been written on the topic for the defense policymaker, the military student, and the private-sector bioscientist interested in the "emerging opportunities market" of national security. This edited volume is intended to help close this gap and provide the necessary backdrop for thinking strategically about biology in defense planning and policymaking. This volume is about applications of the biological sciences, here called "biologically inspired innovations," to the military. Rather than treating biology as a series of threats to be dealt with, such innovations generally approach the biological sciences as a set of opportunities for the military to gain strategic advantage over adversaries. These opportunities range from looking at everything from genes to brains, from enhancing human performance to creating renewable energy, from sensing the environment around us to harnessing its power.
Download or read book Particle Physics Reference Library written by Stephen Myers and published by Springer Nature. This book was released on 2020-01-01 with total page 867 pages. Available in PDF, EPUB and Kindle. Book excerpt: This third open access volume of the handbook series deals with accelerator physics, design, technology and operations, as well as with beam optics, dynamics and diagnostics. A joint CERN-Springer initiative, the "Particle Physics Reference Library" provides revised and updated contributions based on previously published material in the well-known Landolt-Boernstein series on particle physics, accelerators and detectors (volumes 21A,B1,B2,C), which took stock of the field approximately one decade ago. Central to this new initiative is publication under full open access.
Download or read book The Large Hadron Collider written by Lyndon Evans and published by . This book was released on 2018 with total page 305 pages. Available in PDF, EPUB and Kindle. Book excerpt:
