Observation of polarized positrons from an undulator-based source.
An experiment (E166) at the Stanford Linear Accelerator Center has demonstrated a scheme in which a multi-GeV electron beam passed through a helical undulator to generate multi-MeV, circularly polarized photons which were then converted in a thin target to produce positrons (and electrons) with longitudinal polarization above 80% at 6 MeV. The results are in agreement with GEANT4 simulations that include the dominant polarization-dependent interactions of electrons, positrons, and photons in matter.
Tel-Aviv University, Tel Aviv 69978, Israel.
G
G
Alexander
J
J
Barley
Y
Y
Batygin
S
S
Berridge
V
V
Bharadwaj
G
G
Bower
W
W
Bugg
F-J
FJ
Decker
R
R
Dollan
Y
Y
Efremenko
V
V
Gharibyan
C
C
Hast
R
R
Iverson
H
H
Kolanoski
J
J
Kovermann
K
K
Laihem
T
T
Lohse
K T
KT
McDonald
A A
AA
Mikhailichenko
G A
GA
Moortgat-Pick
P
P
Pahl
R
R
Pitthan
R
R
Pöschl
E
E
Reinherz-Aronis
S
S
Riemann
A
A
Schälicke
K P
KP
Schüler
T
T
Schweizer
D
D
Scott
J C
JC
Sheppard
A
A
Stahl
Z M
ZM
Szalata
D
D
Walz
A W
AW
Weidemann