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.
Alexander
G
G
Tel-Aviv University, Tel Aviv 69978, Israel.
Barley
J
J
Batygin
Y
Y
Berridge
S
S
Bharadwaj
V
V
Bower
G
G
Bugg
W
W
Decker
F-J
FJ
Dollan
R
R
Efremenko
Y
Y
Gharibyan
V
V
Hast
C
C
Iverson
R
R
Kolanoski
H
H
Kovermann
J
J
Laihem
K
K
Lohse
T
T
McDonald
K T
KT
Mikhailichenko
A A
AA
Moortgat-Pick
G A
GA
Pahl
P
P
Pitthan
R
R
Pöschl
R
R
Reinherz-Aronis
E
E
Riemann
S
S
Schälicke
A
A
Schüler
K P
KP
Schweizer
T
T
Scott
D
D
Sheppard
J C
JC
Stahl
A
A
Szalata
Z M
ZM
Walz
D
D
Weidemann
A W
AW