The E166 experiment: Undulator-based production of polarized positrons

K. Peter Schüler, G. Alexander, J. Barley, Y. Batygin, S. Berridge, V. Bharadwaj, G. Bower, W. Bugg, F. J. Decker, R. Dollan, Y. Efremenk, V. Gharibyan, C. Hast, R. Iverson, H. Kolanoski, J. Kovermann, K. Laihem, T. Lohse, K. T. McDonald, A. A. MikhailichenkoG. A. Moortgat-Pick, P. Pahl, R. Pitthan, R. Pöschl, E. Reinherz-Aronis, S. Riemann, A. Schälicke, K. P. Schüler, T. Schweizer, D. Scott, J. C. Sheppard, A. Stahl, Z. Szalata, D. Walz, A. Weidemann

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


A proof-of-principle experiment has been carried out in the Final Focus Test Beam (FFTB) at SLAC to demonstrate production of polarized positrons in a manner suitable for implementation at the ILC. A helical undulator of 2.54 mm period and 1-m length produced circularly polarized photons of first harmonic endpoint energy of 8 MeV when traversed by a 46.6 GeV electron beam. The polarized photons were converted to polarized positrons in a 0.2-radiation-length tungsten target. The polarization of these positrons was measured at several energies, with a peak value in excess of 80%, by transmission polarimetry of photons obtained on reconversion of the positrons in a second tungsten target.

Original languageEnglish
Title of host publicationPSTP 2007 - 12th International Workshop on Polarized Ion Sources, Targets and Polarimetry
Number of pages8
StatePublished - 2008
Event12th International Workshop on Polarized Sources, Targets and Polarimetry, PSTP 2007 - Upton, NY, United States
Duration: 10 Sep 200714 Sep 2007

Publication series

NameAIP Conference Proceedings
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616


Conference12th International Workshop on Polarized Sources, Targets and Polarimetry, PSTP 2007
Country/TerritoryUnited States
CityUpton, NY


  • Compton transmission polarimeter
  • Helical undulator
  • ILC
  • Polarized positron source


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