BIW2012 - List of Authors (Enders, J.)

Paper	Title	Page
TUPG023	Wire Scanners for Emittance Measurements at the 100 keV Spin Polarized Electron Beam Line at the S-DALINAC	186
	C. Eckardt, U. Bonnes, J. Enders, Y. Fritzsche, M. Wagner TU Darmstadt, Darmstadt, Germany
	Funding: Work supported by DFG through SFB 634, by the state of Hesse through the LOEWE center HIC for FAIR, and through the GSI-TU Darmstadt cooperation agreement. A source of 100 keV spin polarized electrons * has been installed at the 130 MeV superconducting Darmstadt linear accelerator S-DALINAC*. Circularly polarized laser light excites a GaAs cathode, producing polarized electrons, which are accelerated electrostatically to 100 keV. A Wien-filter for spin manipulation and a Mott polarimeter for polarization measurements are installed in the low-energy beam line. Polarizations up to 86% have been shown with strained superlattice GaAs cathodes. Wire scanners are installed in the beam line for emittance measurements. The scanning unit, two perpendicular 50 micron tungsten wires mounted on an insulated frame, is installed at an angle of 45°. Crossing the beam with each wire yields measurements for the x and y beam size. In conjunction with a solenoid with variable focal length a parameter set of beam sizes depending on the focal length can be obtained, allowing for an emittance calculation. Measurements at the S-DALINAC give an indication of the beam quality of the polarized electron source, permit a comparison with the already installed thermionic electron source, and a possible emittance growth from the Wien-filter is to be excluded. C. Eckardt et al., IPAC 10, Kyoto, p 4083. ** A. Richter, EPAC 96, Sitges, p.110.

Paper

Title

Page

Wire Scanners for Emittance Measurements at the 100 keV Spin Polarized Electron Beam Line at the S-DALINAC

186

C. Eckardt, U. Bonnes, J. Enders, Y. Fritzsche, M. Wagner
TU Darmstadt, Darmstadt, Germany

Funding: Work supported by DFG through SFB 634, by the state of Hesse through the LOEWE center HIC for FAIR, and through the GSI-TU Darmstadt cooperation agreement.
A source of 100 keV spin polarized electrons * has been installed at the 130 MeV superconducting Darmstadt linear accelerator S-DALINAC**. Circularly polarized laser light excites a GaAs cathode, producing polarized electrons, which are accelerated electrostatically to 100 keV. A Wien-filter for spin manipulation and a Mott polarimeter for polarization measurements are installed in the low-energy beam line. Polarizations up to 86% have been shown with strained superlattice GaAs cathodes. Wire scanners are installed in the beam line for emittance measurements. The scanning unit, two perpendicular 50 micron tungsten wires mounted on an insulated frame, is installed at an angle of 45°. Crossing the beam with each wire yields measurements for the x and y beam size. In conjunction with a solenoid with variable focal length a parameter set of beam sizes depending on the focal length can be obtained, allowing for an emittance calculation. Measurements at the S-DALINAC give an indication of the beam quality of the polarized electron source, permit a comparison with the already installed thermionic electron source, and a possible emittance growth from the Wien-filter is to be excluded.
* C. Eckardt et al., IPAC 10, Kyoto, p 4083.
** A. Richter, EPAC 96, Sitges, p.110.