Download or read book Polarized Electron Beams at SLAC written by and published by . This book was released on 1992 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: SLAC has successfully accelerated high energy polarized electrons for the Stanford Linear Collider and fixed polarized nuclear target experiments. The polarized electron beams at SLAC use a gallium arsenide (GaAlAs for E-142) photon emission source to provide the beam of polarized electrons with polarization of approximately 28% (41% for E-142). While the beam emittance is reduced in the damping ring for SLC operation a system of bend magnets and superconducting solenoids preserve and orient the spin direction for maximum longitudinal polarization at the collision point. The electron polarization is monitored with a Compton scattering polarimeter, and was typically 22% at the e[plus]e[minus] collision point for the 1992 run. Improvements are discussed to increase the source polarization and to reduce the depolarization effects between the source and the collision point.
Download or read book Physics Results with Polarized Electrons at SLAC written by and published by . This book was released on 1996 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polarized electron beams can play an important role in the dynamics of interactions at high energies. Polarized electron beams at SLAC have been an important part of the physics program since 1970, when they were first proposed for use in testing the spin structure of the proton. Since 1992, the SLAC linear accelerator and the SLC have operated solely with polarized electrons, providing data for tests of QCD in studies of the spin structure of the nucleon and tests of the electroweak sector of the Standard Model. In the following sections, the performance of the source is summarized, and some of the recent results using the polarized beams are discussed.
Download or read book Polarization at SLAC written by and published by . This book was released on 1995 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: A highly polarized electron beam is a key feature. for the Current physics program at SLAC. An electron beam polarization of 80% can now be routinely achieved for typically 5000 hours of machine operation per year. Two main Physics programs utilize the polarized beam. Fixed target experiments in End Station A study the collision of polarized electrons with polarized nuclear targets to elucidate the spin structure of the nucleon and to provide an important test of QCD. Using the SLAC Linear Collider, collisions of polarized electrons with unpolarized positrons allow precise measurements of parity violation in the Z-fermion couplings and provide a very precise measurement of tile weak mixing angle. This paper discusses polarized beam operation at SLAC, and gives an overview of the polarized physics program.
Download or read book The SLAC Polarized Electron Source and Beam for E 158 written by and published by . This book was released on 2003 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: SLAC E-158 is making the first measurement of parity violation in Moeller scattering. E-158 measures the right-left cross-section asymmetry, A{sub LR}, in the scattering of a 45-GeV polarized electron beam off unpolarized electrons in a liquid hydrogen target. E-158 plans to measure the expected Standard Model asymmetry of (almost equal to) 10−7 to an accuracy of better than 10−8. This paper discusses the performance of the SLAC polarized electron source and beam during E-158's first physics run in April/May 2002.
Download or read book The SLAC Polarized Electron Source written by and published by . This book was released on 1995 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: The SLAC polarized electron source employs a photocathode DC high voltage gun with a loadlock and a YAG pumped Ti:sapphire laser system for colliding beam experiments or a flash lamp pumped Ti:sapphire laser for fixed target experiments. It uses a thin, strained GaAs(100) photocathode, and is capable of producing a pulsed beam with a polarization of ≥80% and a peak current exceeding 10 A. Its operating efficiency has reached 99%. The physics and technology of producing high polarization electron beams from a GaAs photocathode will be reviewed. The prospects of realizing a polarized electron source for future linear colliders will also be discussed.
Download or read book The Polarized Electron Beam for the SLAC Linear Collider written by and published by . This book was released on 1996 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The SLAC Linear Collider has been colliding a polarized electron beam with an unpolarized positron beam at the Z° resonance for the SLD experiment since 1992. An electron beam polarization of close to 80% has been achieved for the experiment at luminosities up to 8 · 1029 cm−2 s−1. This is the world's first and only linear collider, and is a successful prototype for the next generation of high energy electron linear colliders. This paper discusses polarized beam operation for the SLC, and includes aspects of the polarized source, spin transport and polarimetry.
Download or read book Polarized Light Sources for Photocathode Electron Guns at SLAC written by and published by . This book was released on 1992 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: We describe current and future Polarized Light Sources at SLAC for use with photocathode electron guns to produce polarized electron beams. The SLAC experiments SLD and E142 are considered, and are used to define the required parameters for the Polarized Light Sources.
Download or read book Polarization at SLC written by and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The SLAC Linear Collider has been designed to readily accommodate polarized electron beams. Considerable effort has been made to implement a polarized source, a spin rotation system, and a system to monitor the beam polarization. Nearly all major components have been fabricated. At the current time, several source and polarimeter components have been installed. The installation and commissioning of the entire system will take place during available machine shutdown periods as the commissioning of SLC progresses. It is expected that a beam polarization of 45% will be achieved with no loss in luminosity. 13 refs., 15 figs.
Download or read book SLAC s Polarized Electron Source LaserSystem and Minimization of Helicity Correlations for the E 158 Parity Violation Experiment written by and published by . This book was released on 2002 with total page 65 pages. Available in PDF, EPUB and Kindle. Book excerpt: SLAC E-158 is an experiment designed to make the first measurement of parity violation in Moeller scattering. E-158 will measure the right-left cross-section asymmetry, A{sub LR}{sup Moeller}, in the elastic scattering of a 45-GeV polarized electron beam off unpolarized electrons in a liquid hydrogen target. E-158 plans to measure the expected Standard Model asymmetry of (almost equal to) 10−7 to an accuracy of better than 10−8. To make this measurement, the polarized electron source requires for operation an intense circularly polarized laser beam and the ability to quickly switch between right- and left-helicity polarization states with minimal right-left helicity-correlated asymmetries in the resulting beam parameters (intensity, position, angle, spot size, and energy), {sup beam}A{sub LR}'s. This laser beam is produced by a unique SLAC-designed flashlamp-pumped Ti:Sapphire laser and is propagated through a carefully designed set of polarization optics. We analyze the transport of nearly circularly polarized light through the optical system and identify several mechanisms that generate {sup beam}A{sub LR}'s. We show that the dominant effects depend linearly on particular polarization phase shifts in the optical system. We present the laser system design and a discussion of the suppression and control of {sup beam}A{sub LR}'s. We also present results on beam performance from engineering and physics runs for E-158.
Download or read book Review of the SLAC and Les Houches Workshops written by and published by . This book was released on 1994 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polarized Electron Source workshops have been held at varying intervals, beginning in 1983 when Charles Sinclair convened the first at SLAC. Since that time, three workshops were held in conjunction with the International Spin Symposia and two at other occasions. The increasing importance of polarized electron beams at accelerators has stimulated interest in these workshops. Two workshops have been held since the last International Spin Symposium in Nagoya. In 1993, a workshop was held at SLAC, and in 1994 at Les Houches, a polarized electron beam session was held as part of a polarized beam and targets workshop. This report summarizes highlights from the latter two workshops.
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.
Download or read book Beretning om Arbejdet ved Uddybning og Forbedring af Sejll bet til Odense 1920 21 written by and published by . This book was released on 1926 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A High Intensity Highly Polarized Electron Beam for High Energy Physics written by and published by . This book was released on 2002 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new high-energy parity violation (PV) experiment at SLAC as well as particle-physics experiments using future ee− colliders (such as NLC) operating at energies above the scale of unification of the electromagnetic and weak interactions require a highly-polarized electron beam with intensities previously unachievable due to a surface charge limit (SCL) effect at the cathode of the polarized electron source. A newly developed photocathode which allows these high intensities is being used for the SLAC PV experiment E-158. The intensity stability required for stable machine operation is determined by the source laser stability, which has been reduced to 0.5%. Temporal pulse shaping is performed on the laser beam using an improved pulse shaper. Details of the beam generation, energy compensation, and linac performance recently achieved for the SLAC parity violation experiment E-158 are discussed.
Download or read book SLAC s Polarized Electron Source Laser System for the E 158 Parity Violation Experiment written by and published by . This book was released on 2002 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: SLAC E158 is an experiment to make the first measurement of parity violation in Moeller scattering. The left-right cross-section asymmetry in the elastic scattering of a 45-GeV polarized electron beam off unpolarized electrons in a liquid hydrogen target will be measured to an accuracy of better than 10−8, with the expected Standard Model asymmetry being approximately 10−7. An intense circularly polarized laser beam for the polarized electron source is required with the ability to quickly switch between left and right polarization states with minimal left-right asymmetries in the parameters of the electron beam. This laser beam is produced by a unique SLAC-designed, flash-lamp pumped, Ti:Sapphire laser. We present this laser system design and initial results from recent commissioning runs.
Download or read book Polarized Positrons at a Future Linear Collider and the Final Focus Test Beam written by and published by . This book was released on 2004 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Having both the positron and electron beams polarized in a future linear ee− collider is a decisive improvement for many physics studies at such a machine. The motivation for polarized positrons, and a demonstration experiment for the undulator-based production of polarized positrons are reviewed. This experiment (E-166) uses the 50 GeV Final Focus Test electron beam at SLAC with a 1 m-long helical undulator to make (almost equal to) 10MeV polarized photons. These photons are then converted in a thin ((almost equal to) 0.5 radiation length) target into positrons (and electrons) with about 50% polarization.
Download or read book Polarized Electrons written by Joachim Kessler and published by Springer Science & Business Media. This book was released on 2013-03-14 with total page 311 pages. Available in PDF, EPUB and Kindle. Book excerpt: The rapid growth of the subject since the first edition ten years ago has made it necessary to rewrite the greater part of the book. Except for the introductory portion and the section on Mott scattering, the book has been completely revised. In Chap. 3, sections on polarization violating reflection symmetry, on resonance scattering, and on inelastic processes have been added. Chapter 4 has been rewritten, taking account of the numerous novel results obtained in exchange scattering. Chapter 5 includes the recent discoveries on photoelectron polarization produced by unpolarized radiation with unpolarized targets and on Auger-electron polarization. In Chap. 6, a further discussion of relativistic polarization phenomena has been added to the book. The immense growth of polarization studies with solids and surfaces required an extension and new presentation of Chap. 7. All but one section of Chap. 8 has been rewritten and a detailed treatment of polarization analysis has been included. Again, a nearly comprehensive treatment has been attempted. Even so, substantial selectivity among the wide range of available material has been essential in order to accomplish a compact presentation. The reference list, selected along the same lines as in the first edition, is meant to lead the reader through the literature giving a guide for finding further references. I want to express my indebtedness to a number of people whose help has been invaluable.
Download or read book First Results from SLD with Polarized Electron Beam at SLC written by and published by . This book was released on 1992 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: The SLAC Linear Collider (SLC) has been modified to collide a longitudinally polarized electron beam with the unpolarized positron beam. We review the beginning of polarized beam running at the SLC, and report on the measurement of the left-right cross section asymmetry (A[sub LR]) made with a sample of 10,224 Z decays collected over the course of the 1992 run. The average beam polarization for this set of Z decays was 22.4 [plus minus] 0.6%(syst.). A[sub LR] was measured to be 0.100 [plus minus] 0.044(stat.) [plus minus] 0.004(syst.). From this measurement, the weak mixing angle defined at the Z boson pole is determined to be sin[sup 2][theta][sup eff][sub W] = 0.2378 [plus minus] 0.0056 [plus minus] 0.0005.
