skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Polarized Positrons at a Future Linear Collider And the Final Focus Test Beam

Abstract

No abstract prepared.

Authors:
;
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC)
Sponsoring Org.:
USDOE
OSTI Identifier:
876761
Report Number(s):
SLAC-REPRINT-2005-157
TRN: US0601316
DOE Contract Number:
AC02-76SF00515
Resource Type:
Conference
Resource Relation:
Conference: Prepared for 5th International Workshop on Electron-Electron Interactions at TeV Energies, Santa Cruz, California, 12-14 Dec 2003
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ELECTRON-ELECTRON INTERACTIONS; LINEAR COLLIDERS; POSITRONS; Accelerators,ACCPHY

Citation Formats

Weidemann, A.W., and /SLAC /South Carolina U. Polarized Positrons at a Future Linear Collider And the Final Focus Test Beam. United States: N. p., 2006. Web.
Weidemann, A.W., & /SLAC /South Carolina U. Polarized Positrons at a Future Linear Collider And the Final Focus Test Beam. United States.
Weidemann, A.W., and /SLAC /South Carolina U. Mon . "Polarized Positrons at a Future Linear Collider And the Final Focus Test Beam". United States. doi:.
@article{osti_876761,
title = {Polarized Positrons at a Future Linear Collider And the Final Focus Test Beam},
author = {Weidemann, A.W. and /SLAC /South Carolina U.},
abstractNote = {No abstract prepared.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Feb 27 00:00:00 EST 2006},
month = {Mon Feb 27 00:00:00 EST 2006}
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share:
  • Having both the positron and electron beams polarized in a future linear e{sup +}e{sup -} 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 {approx} 10MeV polarized photons. These photons are then converted in a thin ({approx} 0.5 radiation length) target into positrons (and electrons) with about 50% polarization.
  • Having both the positron and electron beams polarized in a future linear e{sup +}e{sup -} 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 {approx} 10MeV polarized photons. These photons are then converted in a thin ({approx} 0.5 radiation length) target into positrons (and electrons) with about 50% polarization.
  • In order to meet their luminosity goals, linear colliders operating in the center-of-mass energy range from 3,50 to 1,500 GeV will need to deliver beams which are as small as a few Manometers tall, with x:y aspect ratios as large as 100. The Final Focus Test Beam (FFTB) is a prototype for the final focus demanded by these colliders: its purpose is to provide demagnification equivalent to those in the future linear collider, which corresponds to a focused spot size in the FFTB of 1.7 microns (horizontal) by 60 manometers (vertical). In order to achieve the desired spot sizes, themore » FFTB beam optics must be tuned to eliminate aberrations and other errors, and to ensure that the optics conform to the desired final conditions and the measured initial conditions of the beam. Using a combination of incoming-beam diagnostics. beam-based local diagnostics, and global tuning algorithms, the FFTB beam size has been reduced to a stable final size of 1.7 microns by 70 manometers. In addition, the chromatic properties of the FFTB have been studied using two techniques and found to be acceptable. Descriptions of the hardware and techniques used in these studies are presented, along with results and suggestions for future research.« less
  • In the proposed E-166 experiment at SLAC, 50 GeV electrons pass through a helical undulator, and produce circularly polarized photons, which interact with a tungsten target and generate longitudinally polarized positrons. The background is an important issue for an experiment under consideration. To address this issue, simulations were performed with the code GEANT3 to model the production of secondary particles from high-energy electrons hitting an undulator. The energy density of photons generated at the target has been analyzed. Results of the simulations are presented and discussed.
  • An interface to the DIMAD beam optics computer program enables the operator to perform in simulation the sequence of magnet adjustments that would be used online for tuning the Stanford Linear Collider Final Focus System. The program accepts any input beam matrix from a disk file and presents a menu of magnet adjustments and scan and display options. The results of a ray trace calculation are presented as profiles or envelope plots on the graphics screen. We give results from studies of the optimization of the beam under various input conditions. 11 refs., 4 figs.