| Paper |
Title |
Page |
| WEPLS051 |
Dark Current Investigation of TTF and PITZ RF Guns
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2493 |
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- L. Monaco, P. Michelato, C. Pagani, P. Pierini, D. Sertore
INFN/LASA, Segrate (MI)
- J.H. Han, S. Schreiber
DESY, Hamburg
- M. Krasilnikov, F. Stephan
DESY Zeuthen, Zeuthen
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The dark current is one of the limiting factor in the operation of RF guns at high gradient. The continuous request of higher brilliance sources and further emittance minimization, leads to apply higher gradients in the RF gun cavity, with the consequence of a significant dark current production. In this context we set up a collaborative effort to identify the dark current sources in the gun, in order to discriminate between the gun and cathode contribution. A critical analysis and organization of dark current measurements, taken during the operation of TTF and PITZ guns, with several cathodes operated at different accelerating fields and solenoids focusing, is presented. Potential areas of improvement are also discussed, together with a possible associated program.
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| WEPLS052 |
High QE Photocathode at FLASH
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2496 |
| |
- D. Sertore, P. Michelato, L. Monaco, C. Pagani
INFN/LASA, Segrate (MI)
- J.H. Han, S. Schreiber
DESY, Hamburg
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The RF gun-based photoinjector of the VUV-FEL/TTF at DESY continues to use high quantum efficiency (QE) photocathodes produced at LASA, Milano. To study the photocathode behavior during beam operation, an online QE monitoring tool has been installed. In this paper, we present the hardware and software setup for the online QE measurement and the results so far obtained. The measured QEs are usually higher than at TTF phase 1. We compare the QE values taken in the RF gun with data measured just after production with a continuous UV light source.
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| TUPCH050 |
Beam Profile Measurements with the 2-D Laser-wire
|
1121 |
| |
- G.A. Blair, I.V. Agapov, S.T. Boogert, G.E. Boorman, A. Bosco, J. Carter, C. Driouichi, M.T. Price
Royal Holloway, University of London, Surrey
- K. Balewski, H.-C. Lewin, F. Poirier, S. Schreiber, K. Wittenburg
DESY, Hamburg
- N. Delerue, D.F. Howell
OXFORDphysics, Oxford, Oxon
- T. Kamps
BESSY GmbH, Berlin
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A new laser-wire system has been installed at the PETRA ring at DESY, Hamburg. The system is set up to scan in two dimensions using piezo-driven mirrors and employs a newly acquired injection seeded Q-switched laser. The system is described and first results are presented.
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| THPCH150 |
Double-pulse Generation with the FLASH Injector Laser for Pump/Probe Experiments
|
3143 |
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- O. Grimm, K. Klose, S. Schreiber
DESY, Hamburg
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The injector laser of the VUV-FEL at DESY, Hamburg, was modified to allow the generation of double-pulses, separated by a few cycles of the 1.3 GHz radio-frequency. Such double pulses are needed for driving the planned infrared/VUV pump/probe facility. Construction constraints of the facility will result in an optical path length about 80 cm longer for the infrared. Although the VUV can be delayed using normal-incidence multilayer mirrors at selected wavelengths, a fully flexible scheme is achieved by accelerating two electron bunches separated by more than the path length difference and then combine the infrared radiation from the first with the VUV from the second. This paper explains schemes for the generation of double-pulses with the laser system. It summarizes experimental studies of the effect on the operation of diagnostic instrumentation and on the tunability of the machine. Of special concern is the effect of wakefields on the quality of the second bunch, critical for achieving lasing.
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