Download or read book Recent Developments on Strained Photocathode Research written by and published by . This book was released on 1998 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: For the past five years, strained GaAs photocathodes have been used for the SLAC polarized electron source producing electron beams having a spin polarization of 78% (85%) for high (low) current operation. Photocathode research has been continuously conducted to understand the cathode characteristics and to improve performances. This paper describes the recent developments in the strained photocathode research at SLAC.
Download or read book Polarization and Charge Limit Studies of Strained GaAs Photocathodes written by and published by . This book was released on 1997 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents studies on the polarization and charge limit behavior of electron beams produced by strained GaAs photocathodes. These photocathodes are the source of high-intensity, high-polarization electron beams used for a variety of high-energy physics experiments at the Stanford Linear Accelerator Center. Recent developments on P-type, biaxially-strained GaAs photocathodes have produced longitudinal polarization in excess of 80% while yielding beam intensities of (approximately) 2.5 A/cm2 at an operating voltage of 120 kV. The SLAC Gun Test Laboratory, which has a replica of the SLAC injector, was upgraded with a Mott polarimeter to study the polarization properties of photocathodes operating in a high-voltage DC gun. Both the maximum beam polarization and the maximum charge obtainable from these photocathodes have shown a strong dependence on the wavelength of illumination, on the doping concentration, and on the negative electron affinity levels. The experiments performed for this thesis included studying the effects of temperature, cesiation, quantum efficiency, and laser intensity on the polarization of high-intensity beams. It was found that, although low temperatures have been shown to reduce the spin relaxation rate in bulk semiconductors, they don't have a large impact on the polarization of thin photocathodes. It seems that the short active region in thin photocathodes does not allow spin relaxation mechanisms enough time to cause depolarization. Previous observations that lower QE areas on the photocathode yield higher polarization beams were confirmed. In addition, high-intensity, small-area laser pulses were shown to produce lower polarization beams. Based on these results, together with some findings in the existing literature, a new proposal for a high-intensity, high-polarization photocathode is given. It is hoped that the results of this thesis will promote further investigation on the properties of GaAs photocathodes.
Download or read book A Polarized Photoluminescence Study of Strained Layer GaAs Photocathodes written by Robin Alexander Mair and published by . This book was released on 1996 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Photodetectors written by Kuan Chee and published by . This book was released on 2019-09-18 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a wide-ranging overview of the current state-of-the-art and new trends in photodetector design and research. Written by a team of internationally renowned experts, with contributions from universities, research institutes and industries, this work is suitable for students and professionals interested in studying and dealing with photodetector design and technology, as well as the wide gamut of related applications. Its coverage includes: physics and fundamentals of photodetectors; physical models of photodetector operation; new materials, design, processing and function of photodetectors in related applications; testing, monitoring and calibration; and research progress in photodetector-related areas. Theoretical aspects, design and simulation principles, and important experimental results are thoroughly addressed, embodying a comprehensive account of current activity in this important field of research and industry.
Download or read book Spin 96 Proceedings Of The 12th International Symposium On High energy Spin Physics written by J E J Oberski and published by World Scientific. This book was released on 1997-04-15 with total page 906 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments using highly polarized intense beams and targets, and theoretical studies of spin and polarization phenomena, are now providing us with numerous additional details of the electroweak and strong interactions and the structure of matter. The spin structure of the nucleon has been measured over wide ranges of kinematic variables, and the cross sections have been calculated to several orders in perturbative field theory. At present, the influence of the higher twist contributions, the gluon spin, and the quark orbital angular momentum are under scrutiny. Quantum chromodynamics (QCD) captures a lot of our experimental knowledge of hard polarized scattering processes. Can our understanding of such processes within QCD be further improved?Hyperons produced in high energy reactions show how puzzling strong interactions between hadrons still are. Spin observables in experiments at intermediate energy are used to test parity and charge symmetries. Will they also reveal, at low energy, a violation of time reversal symmetry? We are on the verge of using parity violation measurements at intermediate electron scattering energies to determine the amount of strange quark contributions to the neutral weak form factor of the nucleon. The polarization of the sea quarks is expected to be measured soon in W± decays produced in high energy polarized proton interactions. Will the jets in polarized Z⁰ decays show a definite handedness? These and many other topics are discussed in these proceedings.
Download or read book Modern Developments in Vacuum Electron Sources written by Georg Gaertner and published by Springer Nature. This book was released on 2020-10-09 with total page 609 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gives an overview of modern cathodes and electron emitters for vacuum tubes and vacuum electron devices in general. It covers the latest developments in field emission theory as well as new methods towards improving thermionic and cold cathodes. It addresses thermionic cathodes, such as oxide cathodes, impregnated and scandate cathodes, as well as photocathodes and field emitters – the latter comprising carbon nanotubes, graphene and Spindt-type emitter arrays. Despite the rise and fall of the once dominant types of vacuum tubes, such as radio valves and cathode ray tubes, cathodes are continually being improved upon as new applications with increased demands arise, for example in electron beam lithography, high-power and high-frequency microwave tubes, terahertz imaging and electron sources for accelerators. Written by 17 experts in the field, the book presents the latest developments in cathodes needed for these applications, discussing the state of the art and addressing future trends.
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 Energy Research Abstracts written by and published by . This book was released on 1995 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Polarization Developments written by and published by . This book was released on 1993 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent developments in laser-driven photoemission sources of polarized electrons have made prospects for highly polarized electron beams in a future linear collider very promising. This talk discusses the experiences with the SLC polarized electron source, the recent progress with research into gallium arsenide and strained gallium arsenide as a photocathode material, and the suitability of these cathode materials for a future linear collider based on the parameters of the several linear collider designs that exist.
Download or read book Spin 2004 Proceedings Of The 16th International Spin Physics Symposium And Workshop On Polarized Electron Sources And Polarimeters With Cd rom written by Franco Bradamante and published by World Scientific. This book was released on 2005-08-02 with total page 1065 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive volume covers the most recent advances in the field of spin physics, including the latest research in high energy and nuclear physics and the study of nuclear spin structure. The comprehensive coverage also includes polarized proton and electron acceleration and storage as well as polarized ion sources and targets. Many significant new results and achievements on the different topics considered at the symposium are presented in this book for the first time.
Download or read book Laboratory Directed Research and Development written by Lawrence Livermore National Laboratory and published by . This book was released on 1992 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Current Trends in International Fusion Research written by E. Panarella and published by NRC Research Press. This book was released on 1999 with total page 514 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of a symposium held to identify, review, and assess the benefits, uncertainties, & potentialities of the conventional, alternative, & exploratory approaches to fusion energy production, and to assess industrial spin-offs & other applications. Topics of the compiled papers include: a new course for fusion research, magnetic confinement, inertial confinement, other confinement, plasma physics, numerical simulation, nuclear processes, fusion burn control, plasma diagnostics, and plasma stability. Includes subject index.
Download or read book InP and Related Compounds written by M O Manasreh and published by CRC Press. This book was released on 2000-08-08 with total page 862 pages. Available in PDF, EPUB and Kindle. Book excerpt: InP is a key semiconductor for the production of optoelectronic and photonic devices. Its related compounds, such as InGaAsP alloy, have been realized as very important materials for communication in the 1.3 and 1.55 micron spectral regions. Furthermore, the applications on InP and related compounds have extended to other areas that include laser d
Download or read book Proceedings written by and published by . This book was released on 1995 with total page 772 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy and Water Development Appropriations for 1996 Department of Energy fiscal year 1996 budget justifications written by United States. Congress. House. Committee on Appropriations. Subcommittee on Energy and Water Development and published by . This book was released on 1995 with total page 2690 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Perspectives In Hadronic Physics Proceedings Of The Conference written by Sigfrido Boffi and published by World Scientific. This book was released on 1997-12-16 with total page 578 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Polarized Beams And Polarized Gas Targets Proceedings Of The International Workshop written by Hans Paetz Gen Schieck and published by World Scientific. This book was released on 1996-03-21 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: The International Workshop on Polarized Beams and Polarized Gas Targets was held in Cologne, Germany from June 6 to 9, 1995 as the last in a series held at 2-3 years intervals. It was attended by about 110 scientists; there were 47 invited and contributed talks, 5 round-table discussions and 17 poster contributions, all of which will appear as a written contribution in the Proceedings. The main subjects were Optically-Pumped Polarized Targets, Polarized Electron Sources, Atomic-Beam Polarized-Ion Sources, Optically-Pumped Polarized Ion Sources, Targets and Storage Rings. Significant progress and latest developments in this field were covered as well as future developments both from the technical, but also from the physics aspects.
