Download or read book RF Guns for Generation of Polarized Electron Beams written by R. E. Kirby and published by . This book was released on 2005 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Several accelerators, including the SLC, JLAB, Mainz, Bates/MIT, and Bonn have successfully operated for medium and high energy physics experiments using polarized electron beams generated by dc-biased guns employing GaAs photocathodes. Since these guns have all used a bias on the order of 100 kV, the longitudinal emittance of the extracted bunch is rather poor. Downstream rf bunching systems increase the transverse emittance. An rf gun with a GaAs photocathode would eliminate the need for separate rf bunchers, resulting in a simpler injection system. In addition, the thermal emittance of GaAs-type cathodes is significantly lower than for other photocathode materials. The environmental requirements for operating activated GaAs photocathodes cannot be met by rf guns as currently designed and operated. These requirements, including limits on vacuum and electron back bombardment, are discussed in some detail. Modifications to actual and proposed rf gun designs that would allow these requirements to be met are presented.
Download or read book Prospects for Generating Polarized Electron Beams for a Linear Collider Using an RF Gun written by and published by . This book was released on 1993 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: The next generation of linear colliders--represented by the Japanese Linear Collider (JLC) and the Next Linear Collider (NLC)--will probably utilize polarized electrons generated by a photocathode gun. A photocathode gun with high polarization (P{sub e}) photocathodes (up to Pe(approximately)80% achieved to date) is currently providing polarized electrons for the SLC. The SLC source requires subharmonic bunching at low energy to reduce the bunch length prior to S-band bunching and a damping ring at high energy to reduce the transverse emittance. The use of an RF gun can eliminate the former and possibly simplify the latter. However, RF guns as presently developed have serious problems with vacuum contamination, which would quickly lower the quantum efficiency (QE) of a semiconductor photocathode. In addition, the ''charge limit'' previously reported for high peak current pulses puts a limit on the laser power usable for photoexciting a low QE cathode near the bandgap threshold. These problems have so far precluded any serious attempt to design an RF gun for polarized electrons. Several technical advances that now improve the prospects for a practical polarized electron RF gun are described. Finally, new ideas for high polarization photocathodes that permit operation in a relatively poor vacuum and techniques being explored to mitigate the low QE ''charge-limit'' are discussed.
Download or read book Polarized Sources Targets And Polarimetry Proceedings Of The 13th International Workshop written by Marco Contalbrigo and published by World Scientific. This book was released on 2011-01-19 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book collects the most recent experimental results, new ideas and prototypes in the field of nuclear gaseous and solid polarized targets and polarimetry. It contains the contribution of the biennial meeting on the topics of Polarized Sources, Targets and Polarimetry. Therefore includes the most recent developments and performances in the field and new proposals. The contributing authors are the experts of the field.The topics covered include: Polarized Electron Sources, Polarized Proton and Deuterium Sources, Polarized Internal Targets, Polarized 3He Ion Sources and Targets, Polarimetry (e, p, d) at Low and High Energy, Polarized antiprotons, Polarized Solid Targets.br>
Download or read book Polarized Sources And Targets Proceedings Of The Eleventh International Workshop written by Akihiro Yoshimi and published by World Scientific. This book was released on 2007-04-26 with total page 269 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polarized beams and targets have been irreplaceable tools in nuclear and particle physics experiments for a long time and have provided us rich information on the role played by spin-degrees of freedom in the sub-nuclear world. In addition, techniques to obtain large nuclear polarization have recently been applied to new fields such as materials and medical sciences.The scope of these proceedings covers recent progress of state-of-the-art techniques in spin polarization, the cryogenic method, the atomic beam method, the optical pumping method and the nuclear reaction method.
Download or read book Polarized RF Guns written by and published by . This book was released on 1998 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: RF guns employing photocathodes are now well established as viable electron sources for accelerator applications. For high energy accelerators the desirable properties of such sources include the relative ease of pulse formation (using the source laser system to establish the pulse shape and number) and a low transverse beam emittance, eliminating the need for rf chopping and bunching systems and reducing the demands on emittance-reducing damping rings. However, most high-energy accelerators now require polarized electrons. Polarized electron beam scan in principle be generated by substituting a 3--5 semiconductor, such as GaAs, for the traditional photocathode in a conventional rf gun structure. In the past, the principal criterion for selection of photocathodes for rf guns has been the ability to maintain a reasonable quantum yield from the cathode over a relatively long operating period. It is well known that GaAs is significantly more sensitive to the vacuum environment than any of the cathode types that have been used to date. However, advances in the understanding of how to operate GaAs cathodes in hostile environments combined with similar advances in the ability to prepare gun structures that will significantly reduce dark current and rf breakdown lend credibility to the prospect of successfully operating an rf gun with the activated GaAs cathode. The status of research related to polarized rf guns is reviewed and the outline of a future polarized rf source combining the best of what is known. Today.
Download or read book The Polarized SRF Gun Experiment written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: RF electron guns are capable of producing electron bunches with high brightness, which outperform DC electron guns and may even be able to provide electron beams for the ILC without the need for a damping ring. However, all successful existing guns for polarized electrons are DC guns because the environment inside an RF gun is hostile to the GaAs cathode material necessary for polarization. While the typical vacuum pressure in a DC gun is better than 10−11 torr the vacuum in an RF gun is in the order of 10−9 torr. Experiments at BINP Novosibirsk show that this leads to strong ion back-bombardment and generation of dark currents, which destroy the GaAs cathode in a short time. The situation might be much more favorable in a (super-conducting) SRF gun. The cryogenic pumping of the gun cavity walls may make it possible to maintain a vacuum close to 10−12 torr, solving the problem of ion bombardment and dark currents. Of concern would be contamination of the gun cavity by evaporating cathode material. This report describes an experiment that Brookhaven National Laboratory (BNL) in collaboration with Advanced Energy Systems (AES) is conducting to answer these questions.
Download or read book Polarized RF Guns for Linear Colliders written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The ICFA Workshop on Polarized RF Guns for Linear Colliders was held at Fermilab during April 18-20, 2001. It was attended by 37 scientists from 14 institutions. A list of participants is appended. An RF photoemission gun that delivers polarized electrons at low emittance would be an attractive electron source for a linear collider. Moreover, recently it has been demonstrated that an RF gun in conjunction with nearby injection system optics can deliver a beam with a high ratio of transverse emittances; a simplification of a linear collider's damping system could result. However, at present RF electron gun technology has not developed sufficiently to assure that such a source is feasible. The purpose of the workshop was to review the status of polarized RF gun development with linear collider application in mind, and outline a possible program for the future. A table lists the requirements for the electron injector for proposed linear colliders. The specifications are given for the beam before and after the electron damping ring.
Download or read book SPIN 2002 written by Yousef I. Makdisi and published by American Institute of Physics. This book was released on 2003-09-04 with total page 1198 pages. Available in PDF, EPUB and Kindle. Book excerpt: The SPIN 2002 Proceedings describe the recent advances in the field of spin physics. The topics cover research in high energy and nuclear physics and the study of the nuclear spin structure. The symposium also covers advances in polarized proton and electron acceleration and storage as well as polarized ion sources and targets. The first measurement of spin physics observables in pp collisions at center of mass energy of 200 Gev was announced at this symposium.
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 Progress on Using NEA Cathodes in an RF Gun written by T. Anderson and published by . This book was released on 2005 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: RF guns have proven useful in multiple accelerator applications, and are an attractive electron source for the ILC. Using a NEA GaAs photocathode in such a gun allows for the production of polarized electron beams. However the lifetime of a NEA cathode in this environment is reduced by ion and electron bombardment and residual gas oxidation. We report progress made with studies to produce a RF gun using a NEA GaAs photocathode to produce polarized electron beams. We discuss simulations of ion back bombardment and attempts to reduce the residual gas pressure in the gun are discussed. Future directions are also discussed.
Download or read book Progress on a Cryogenically Cooled RF Gun Polarized Electron Source written by H. Edwards and published by . This book was released on 2006 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: RF guns have proven useful in multiple accelerator applications. An RF gun capable of producing polarized electrons is an attractive electron source for the ILC or an electron-ion collider. Producing such a gun has proven elusive. The NEA GaAs photocathode needed for polarized electron production is damaged by the vacuum environment in an RF gun. Electron and ion back bombardment can also damage the cathode. These problems must be mitigated before producing an RF gun polarized electron source. In this paper we report continuing efforts to improve the vacuum environment in a normal conducting RF gun by cooling it with liquid nitrogen after a high temperature vacuum bake out. We also report on a design of a cathode preparation chamber to produce bulk GaAs photocathodes for testing in such a gun. Future directions are also discussed.
Download or read book Unifying Physics of Accelerators Lasers and Plasma written by Andrei Seryi and published by CRC Press. This book was released on 2023-04-30 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unifying Physics of Accelerators, Lasers and Plasma introduces the physics of accelerators, lasers and plasma in tandem with the industrial methodology of inventiveness, a technique that teaches that similar problems and solutions appear again and again in seemingly dissimilar disciplines. This unique approach builds bridges and enhances connections between the three aforementioned areas of physics that are essential for developing the next generation of accelerators. A Breakthrough by Design approach, introduced in the book as an amalgam of TRIZ inventive principles and laws of technical system evolution with the art of back-of-the-envelope estimations, via numerous examples and exercises discussed in the solution manual, will make you destined to invent. Unifying Physics of Accelerators, Lasers and Plasma outlines a path from idea to practical implementation of scientific and technological innovation. This second edition has been updated throughout, with new content on superconducting technology, energy recovery, polarization, various topics of advanced technology, etc., making it relevant for the Electron-Ion Collider project, as well as for advanced lights sources, including Free Electron Lasers with energy recovery. The book is suitable for students at the senior undergraduate and graduate levels, as well as for scientists and engineers interested in enhancing their abilities to work successfully on the development of the next generation of facilities, devices and scientific instruments manufactured from the synergy of accelerators, lasers and plasma. Key Features: Introduces the physics of accelerators, lasers, and plasma in tandem with the industrial methodology of inventiveness. Outlines a path from idea to practical implementation of scientific and technological innovation. Contains more than 380 illustrations and numerous end-of-chapter exercises. Solutions manual is included into the book. Boasting more than 380 illustrations, this highly visual text: Employs TRIZ to amalgamate and link different areas of science Avoids heavy mathematics, using back-of-the-envelope calculations to convey key principles Introduces the Innovation by Design approach based an amalgam of TRIZ inventive principles and laws of technical system evolution with the art of back-of-the-envelope estimations – developing and applying this methodology, you will be destined to invent Includes updated materials for all eleven chapters of the first edition, e.g., the FEL invention path analysis, etc. The second edition includes new chapters: Beam Cooling and Final Focusing, Beam Stability and Energy Recovery, Advanced Technologies The new chapters add topics such as superconducting magnets and accelerating cavities, polarized beams, energy recovery – themes relevant for new projects such as Electron-Ion Collider, or Free Electron Laser based on energy recovery for science or industry The second edition also includes a new chapter with illustrations of 40 inventive principles of TRIZ based on the areas of accelerator, laser and plasma technology Every chapter includes invention case studies, often making important connections to adjacent areas of technologies, illustrated by the case of EUV light generation invention for semiconductor lithography, etc. Includes end-of-chapter exercises focusing on physics and on applications of the inventiveness method, on reinventing technical systems and on practicing back-of-the-envelope estimations; and also includes mini-projects, suitable for exercises by teams of students Includes a detailed Guide to solutions of the exercises, discussing the inventions and highlighting the relevant inventive principles, as well as directions of mini-projects Includes discussion of the TRIZ laws of evolution of technical systems and makes bold predictions for the Year 2050 for accelerator, laser and plasma technology Praise for the first edition "...Unifying Physics of Accelerators, Lasers and Plasma is a must-have for every student and practitioner of accelerator science. It is a quick reference guide and provides solid, intuitive discussions of what are often quite erudite concepts. I enthusiastically applaud this outstanding book." Sekazi Mtingwa in Physics Today, August 2016
Download or read book The Physics and Applications of High Brightness Electron Beams written by Jamie Rosenzweig and published by World Scientific. This book was released on 2003 with total page 563 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains the contributions to the Workshop on the Physics and Applications of High Brightness Electron Beams, held in July 2002 in Sardinia, Italy. This workshop had a broad international representation from the fields of intense electron sources, free-electron lasers, advanced accelerators, and ultra-fast laser-plasma, beam-plasma and laser-beam physics. The interdisciplinary participants were brought together to discuss advances in the creation and understanding of ultra-fast, ultra-high brightness electron beams, and the unique experimental opportunities in frontier high-energy-density and radiation-source physics which are offered by these scientific tools.The proceedings have been selected for coverage in: ? Index to Scientific & Technical Proceedings? (ISTP? / ISI Proceedings)? Index to Scientific & Technical Proceedings (ISTP CDROM version / ISI Proceedings)
Download or read book Physics Briefs written by and published by . This book was released on 1994 with total page 1162 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Initial Test of an Rf Gun with a GaAs Cathode Installed written by and published by . This book was released on 1996 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The operation of an rf gun with a GaAs crystal installed as the cathode has been tested in anticipation of eventually producing a polarized electron beam for a future e/e− collider using an rf photoinjector.
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1974 with total page 764 pages. Available in PDF, EPUB and Kindle. Book excerpt:
