Mainz 2012 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 52: Poster – Beschleuniger

HK 52.9: Poster

Donnerstag, 22. März 2012, 14:00–16:00, P Foyer

Performance of and Atomic Hydrogen Cleaning for Semiconductor-Photocathodes at the S-DALINAC — •Neeraj Kurichiyanil¹, Kurt Aulenbacher², Christian Eckardt¹, Joachim Enders¹, Martin Espig¹, Yuliya Fritzsche¹, and Markus Wagner¹ — ¹Institute for Nuclear Physics, TU Darmstadt — ²Institute for Nuclear Physics, University of Mainz

We report on the performance of semiconductor photocathodes at the source of polarized electrons at the Darmstadt superconducting electron linear accelerator S-DALINAC. Vacuum lifetimes of above 1000 hours and charge lifetimes of 54 C have been achieved between repeated activation cycles. A standalone photocathode-rejuvenating system using atomic hydrogen is being designed for use at the S-DALINAC. In the present two-chamber design cleaning and activation of the cathodes will be carried out in a single chamber and a high-voltage (<10 kV) electrode in the second chamber will be used to test the cathodes. Inclusion of a transport vessel to the system enables fast transfer of cleaned photocathodes to main source of the accelerator. A beam of up to 10 keV polarized electrons will be available for performing quantum efficiency measurements and additional experiments. Improvement of vacuum and charge lifetimes of the cathode through systematic study of the factors causing cathode-deterioration is one of the objectives. Cathode performance is crucial for future applications of high-brightness polarized beams such as energy-recovery accelerator schemes or polarized electron targets. Supported by DFG through SFB 634 and by the state of Hesse within the LOEWE centre HIC for FAIR.