Speaker
Mr
Christian Eckardt
(TU Darmstadt)
Description
The spin polarized electron source at the Darmstadt superconducting linear accelerator S-DALINAC is operating at 100 keV. Polarized electrons are extracted by stimulation of a GaAs cathode with circular polarized laser light. Pulsed laser beams with a repetition frequency of 3 GHz provide electron bunches with pulse lengths in the region of 50 ps and smaller. A Wien-filter for spin manipulation and a Mott polarimeter for polarization measurements are installed in the beam line. Polarizations up to 86% have been shown with strained superlattice GaAs cathodes. Wire scanners in the beam line measure beam radius and position and in conjunction with a solenoid the beam emittance. One wire scanner up- and downstream of the Wien-filter are used to exclude emittance growth from the Wien-filter. Further use is in the knowledge of the beam size for a slit measurement of the beam pulse length and as a diagnostic tool for the beam position for an automatic beam alignment. The wire scanners are installed at an angle of 45° in a plane perpendicular to the beam with two 50 micron tungsten wires for x and y mounted on an insulated aluminum frame. Pneumatic as well as electric translation is used while the read-out is done by a 24-bit ADC with variable reading speed. First measurements at the S-DALINAC will be shown.
Author
Mr
Christian Eckardt
(TU Darmstadt)
Co-authors
Prof.
Joachim Enders
(TU Darmstadt)
Mr
Markus Wagner
(TU Darmstadt)
Ms
Yuliya Fritzsche
(TU Darmstadt)