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MOOBNO02 |
FEL Operation With the Superconducting RF Photo Gun at ELBE |
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- J. Teichert, A. Arnold, H. Büttig, M. Justus, U. Lehnert, P.N. Lu, P. Michel, P. Murcek, R. Schurig, W. Seidel, H. Vennekate, R. Xiang
HZDR, Dresden, Germany
- T. Kamps, J. Rudolph
HZB, Berlin, Germany
- I. Will
MBI, Berlin, Germany
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The superconducting RF photoinjector (SRF gun) operating with a 31/2-cell niobium cavity and Cs2Te photocathodes is installed at the ELBE radiation center. The gun provides beams for ELBE as well as in a separate diagnostics beam line for beam parameter measurements. Since 2012 a new UV driver laser system developed by MBI has been installed for the SRF gun . It delivers CW or bust mode pulses with 13 MHz repetition rate or with reduced rates of 500, 200, and 100 kHz at an average UV power of about 1 W. The new laser allows the gun to serve as the driver for the infrared FELs at ELBE. In the first successful experiment a 250 μA beam with 3.3 MeV from SRF gun was injected into ELBE, further accelerated in the ELBE superconducting linac modules and then guided to the U100 undulator. First lasing was achieved at the wavelength of 41 μm. The spectrum, detuning curve and further parameters were measured.
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Slides MOOBNO02 [7.458 MB]
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| MOPSO76 |
FEL Operation With the Superconducting RF Photo Gun at ELBE |
136 |
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- J. Teichert, A. Arnold, H. Büttig, M. Justus, U. Lehnert, P.N. Lu, P. Michel, P. Murcek, R. Schurig, W. Seidel, H. Vennekate, R. Xiang
HZDR, Dresden, Germany
- T. Kamps, J. Rudolph
HZB, Berlin, Germany
- I. Will
MBI, Berlin, Germany
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The superconducting RF photoinjector (SRF gun) operating with a 31/2-cell niobium cavity and Cs2Te photocathodes is installed at the ELBE radiation center. The gun provides beams for ELBE as well as in a separate diagnostics beam line for beam parameter measurements. Since 2012 a new UV driver laser system developed by MBI has been installed for the SRF gun . It delivers CW or bust mode pulses with 13 MHz repetition rate or with reduced rates of 500, 200, and 100 kHz at an average UV power of about 1 W. The new laser allows the gun to serve as the driver for the infrared FELs at ELBE. In the first successful experiment a 250 μA beam with 3.3 MeV from SRF gun was injected into ELBE, further accelerated in the ELBE superconducting linac modules and then guided to the U100 undulator. First lasing was achieved at the wavelength of 41 μm. The spectrum, detuning curve and further parameters were measured.
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| TUPSO44 |
Transverse Emittance Measurement by Slit-scan Method for an SRF Photo Injector |
322 |
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- P.N. Lu, A. Arnold, P. Michel, P. Murcek, J. Teichert, H. Vennekate, R. Xiang
HZDR, Dresden, Germany
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Funding: European Community-Research Infrastructure Activity German Federal Ministry of Education and Research Grant 05 ES4BR1/8, LA³NET funding, Grant Agreement Number GA-ITN-2011-289191
A 3½-cell SRF-gun has been developed and commissioned in Helmholtz-Zentrum Dresden-Rossendorf (HZDR) since 2004. The emittance of this gun was measured before by both solenoid/quadrupole scanning method and multiple slits method. Recently we did new measurements by single slit scanning method which outputs a detailed phase space with higher space resolution and no overlapping problem. This contribution will first describe our diagnostics beam line and software functions, focusing on data processing algorithm. Then an investigation will be presented on the emittance dependence on several important gun parameters as bunch charge, laser phase and DC voltage on the photo cathode. For the bunch charge, a linear increasing relation with the emittance was found. Lower laser phase and higher DC voltage result in lower beam emittance. The influence of a downstream solenoid is studied for the preliminary understanding of the emittance compensation. The contribution will discuss the measurement errors and compare results with other methods. Also, ASTRA simulations of the SRF-gun beams with same parameters will be presented which have similar trends like our measurements.
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| TUPSO92 |
Dark Current Measurements at the Rossendorf SRF Gun |
455 |
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- R. Xiang, A. Arnold, P.N. Lu, P. Murcek, J. Teichert, H. Vennekate
HZDR, Dresden, Germany
- R. Barday, T. Kamps
HZB, Berlin, Germany
- V. Volkov
BINP SB RAS, Novosibirsk, Russia
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Funding: the European Community-Research Infrastructure Activity (EuCARD, contract number 227579) and the German Federal Ministry of Education and Research grant 05 ES4BR1/8
In high gradient photo injectors electron field emission creates so-called dark current. The dark current produces beam loss that increases the radiation level, causes damages to the accelerator components, and produces additional background for the users. Field emitted electrons which stay inside the gun, increases RF power consumption and heat load for the superconducting cavities. It is also believed that dark current is the source of local outgassing and plasma formation which can damage sensitive photocathodes. Thus, to understand and control the dark current has become increasingly important for accelerators. In this presentation, we report on dark current measurement at the ELBE SRF Gun at HZDR. The measurements were carried out with the 3.5 cell-cavity SRF gun and Cs2Te photocathodes. We discuss the dark current behavior for different cavity gradients and various solenoid fields. Simulations have been done to understand the experimental results.
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