Würzburg 2018 – scientific programme

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AKBP: Arbeitskreis Beschleunigerphysik

AKBP 8: Poster session

AKBP 8.14: Poster

Wednesday, March 21, 2018, 18:00–19:30, NW-Bau - HS2

Setup for cooled GaAs cathodes with increased charge lifetime — •Tobias Eggert, Markus Wagner, Yuliya Fritzsche, Neeraj Kurichiyanil, and Joachim Enders — Institute for Nuclear Physics, TU Darmstadt

For high-current applications of GaAs photocathodes it is necessary to maximize the charge lifetime of the cathode material to ensure reliable operation. By means of cryogenic cooling of the electrode, the local vacuum conditions around the GaAs cathode, with its sensitive negative-electron-affinity surface, are expected to improve due to cryogenic adsorption of reactive residual gas molecules at the surrounding walls. Furthermore, the cooling also allows a higher laser power deposited in the material, resulting in higher currents that can be extracted from the cathode. Ion-backbombardment is expected to be reduced using an electrostatic bend after the electrons leave the cathode. To measure the characteristics of such an electron source, a dedicated set-up is being developed at the Photo-CATCH test facility (Proc. 7th DAE-BRNS Indian particle accelerator conference, Mumbai 2015) in Darmstadt, Germany. We will present the current status of the source, including electrostatic and vaccum simulations and future plans.

The project is funded by DFG (GRK 2128) and BMBF (05H15RDRB1).