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WG106 |
Status and Perspectives of SRF Photoinjector Development for BERLinPro |
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- T. Kamps, W. Anders, R. Barday, A. Burrill, A. Jankowiak, J. Knobloch, O. Kugeler, A.N. Matveenko, A. Neumann, E. Panofski, M. Schmeißer, J. Völker
HZB, Berlin, Germany
- A. Ferrarotto, T. Weis
DELTA, Dortmund, Germany
- S.G. Schubert
BNL, Upton, Long Island, New York, USA
- V.I. Shvedunov
MSU, Moscow, Russia
- J. Teichert
HZDR, Dresden, Germany
- I. Will
MBI, Berlin, Germany
- E.N. Zaplatin
FZJ, Jülich, Germany
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The energy recovery linac (ERL) test facility BERLinPro asks for an electron source delivering a beam with low emittance and high average current. The SRF photoinjector concept is a suitable candidate for such an ERL class electron source. After successful running of an SRF photoinjector with superconding Pb cathode we are now concentrating on the next stage of the R&D programme. The talk will present an overview of current and planned activities, related to GunLab, the gun test facility of BERLinPro, high QE photocathodes and additional test setups probing operational limits of photoinjectors.
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Slides WG106 [3.351 MB]
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| WG503 |
Dark Current in Superconducting RF Photoinjectors – Measurements and Mitigation |
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- J. Teichert, A. Arnold, P.N. Lu, P. Murcek, G.S. Staats, H. Vennekate, R. Xiang
HZDR, Dresden, Germany
- R. Barday, T. Kamps
HZB, Berlin, Germany
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Unwanted beam can cause beam losses and may produce acute or chronic damages of the accelerator. Furthermore it can considerably disturb experiments or increase its back-ground. The operation of the superconducting RF photo gun at the ELBE accelerator has delivered the first experimental information on that topic. It was found, that dark current is an important issue, similar to that normal conducting RF photo injectors. In the presentation the measurement of dark current, its properties and analysis will be shown and we will discuss ways for mitigation, especially the construction of a dark current kicker.
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Slides WG503 [2.864 MB]
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WG504 |
Field Emission Measurements on Flat Mo-substrates |
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- R. Barday, A. Burrill, A. Jankowiak, T. Kamps, C. Klimm, J. Knobloch, F. Siewert
HZB, Berlin, Germany
- S. Lagotzky, G. Müller
Bergische Universität Wuppertal, Wuppertal, Germany
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Funding: Work supported by Bundesministerium für Bildung und Forschung and Land Berlin.
Bi-alkali antimonide K2CsSb is a baseline photocathode material for the production of a high brightness electron beam with high average current for future 4th generation multi-user light sources. The low beam emittance required for these projects demands very high field gradient on the photocathode surface, increasing the probability of enhanced field emission (EFE) in the superconducting gun cavity. Molybdenum can be used as a substrate to reduce the lattice mismatch with the cathode crystal. Therefore we have measured the EFE from a flat Mo sample by means of field emission scanning microscopy (FESM) up to 180 MV/m surface field (Es). First EFE (1 nA) was noticed at Es = 60 MV/m, but a strong emitter activation resulted in a finally lower EFE onset at Es = 46 MV/m. Local I(E) measurements have revealed Fowler-Nordheim behavior with enhancement factors of 10-70, however with a wide range of emitting areas (0.1 nm2 - 4300 μm2) which hint for adsorbate or oxide effects. Finally the located emission areas were investigated by SEM/EDX to identify the origin of the EFE.
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Slides WG504 [3.581 MB]
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