IPAC2018 - List of Authors (Arnold, A.)

Paper	Title	Page
THPAL074	Numerical Studies of Normal Conducting Deflecting Cavity Designs for the ELBE Accelerator	3824
SUSPL066	use link to see paper's listing under its alternate paper code
	T.G. Hallilingaiah, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany A. Arnold, U. Lehnert, P. Michel HZDR, Dresden, Germany
	Currently, in the electron linac ELBE there is a single beam line. Therefore, at any given time only single user can use the beam. Moreover, as different user experiments require distinct beam intensity settings, not all the experiments fully utilize the 13 MHz CW beam capability of the facility. To utilize the full beam capacity, multiple beam lines can be established by using an array of transverse deflecting structures. For that, an RF cavity was the design choice due to its inherent advantages with respect to repeatability of the kick voltage amplitude and phase, and the possibility of CW operation in the MHz range. Potential design candidates are the CEBAF RF separator, the three proposed crab cavities for the HL-LHC upgrade project, and a novel NC deflecting cavity design. In this comparative study, the figures of merit of the cavities are computed from electromagnetic field simulations for a transverse voltage of 300 kV. This comparative study supported our selection of the deflecting cavity design for ELBE.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL074
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THPMF039	Study of Magnesium Photocathodes for Superconducting RF Photoinjectors	4142
	R. Xiang, A. Arnold, P.N. Lu, P. Murcek, J. Teichert, H. Vennekate HZDR, Dresden, Germany
	Funding: The work is supported by the German Federal Ministry of Education and Research (BMBF) grant 05K12CR1. The superconducting RF photoinjector (SRF Gun II) has successfully served for the ELBE user facility at HZDR. Nevertheless, the quality of photocathodes is one of the most critical issues in improving the stability and reliability for its application. Magnesium has a comparably low work function (3.6 eV) and shows a quantum efficiency up to 0.3% after laser cleaning. However, the present cleaning process with a high intensity laser beam is time consuming and produces unwanted surface roughness, which leads to a higher thermal emittance. Thermal treatment and Excimer laser cleaning for Mg cathodes are investigated as alternative methods. In this work, the new cleaning procedures are tested and optimized, and the quantum efficiency of Mg samples with different microstructure, composition and suppliers are compared.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF039
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THPMF040	Experiences with the SRF Gun II for User Operation at the ELBE Radiation Source	4145
	J. Teichert, A. Arnold, M. Bawatna, P.E. Evtushenko, M. Gensch, B.W. Green, S. Kovalev, U. Lehnert, P.N. Lu, P. Michel, P. Murcek, H. Vennekate, R. Xiang HZDR, Dresden, Germany
	Funding: The work is supported by the German Federal Ministry of Education and Research (BMBF) grant 05K12CR1. The second version of the superconducting RF pho-toinjector (SRF Gun II) was successfully commissioned at the ELBE radiation source in 2014. The gun features an improved 3.5-cell niobium cavity combined with a super-conducting solenoid integrated in the cryostat. With a Mg photocathode the SRF Gun II is able to generate bunches with up to 200 pC and with sub-ps length in CW mode with 100 kHz pulse frequency for the THz radiation fa-cility at ELBE. In the ELBE linac, the beam is accelerat-ed, gets a proper correlated energy spread, and is com-pressed in a magnetic chicane. Sub-ps pulses are obtained producing coherent diffraction radiation and superradiant undulator radiation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF040
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Paper

Title

Page

THPAL074

Numerical Studies of Normal Conducting Deflecting Cavity Designs for the ELBE Accelerator

3824

SUSPL066

use link to see paper's listing under its alternate paper code

T.G. Hallilingaiah, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
A. Arnold, U. Lehnert, P. Michel
HZDR, Dresden, Germany

Currently, in the electron linac ELBE there is a single beam line. Therefore, at any given time only single user can use the beam. Moreover, as different user experiments require distinct beam intensity settings, not all the experiments fully utilize the 13 MHz CW beam capability of the facility. To utilize the full beam capacity, multiple beam lines can be established by using an array of transverse deflecting structures. For that, an RF cavity was the design choice due to its inherent advantages with respect to repeatability of the kick voltage amplitude and phase, and the possibility of CW operation in the MHz range. Potential design candidates are the CEBAF RF separator, the three proposed crab cavities for the HL-LHC upgrade project, and a novel NC deflecting cavity design. In this comparative study, the figures of merit of the cavities are computed from electromagnetic field simulations for a transverse voltage of 300 kV. This comparative study supported our selection of the deflecting cavity design for ELBE.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL074

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMF039

Study of Magnesium Photocathodes for Superconducting RF Photoinjectors

4142

R. Xiang, A. Arnold, P.N. Lu, P. Murcek, J. Teichert, H. Vennekate
HZDR, Dresden, Germany

Funding: The work is supported by the German Federal Ministry of Education and Research (BMBF) grant 05K12CR1.
The superconducting RF photoinjector (SRF Gun II) has successfully served for the ELBE user facility at HZDR. Nevertheless, the quality of photocathodes is one of the most critical issues in improving the stability and reliability for its application. Magnesium has a comparably low work function (3.6 eV) and shows a quantum efficiency up to 0.3% after laser cleaning. However, the present cleaning process with a high intensity laser beam is time consuming and produces unwanted surface roughness, which leads to a higher thermal emittance. Thermal treatment and Excimer laser cleaning for Mg cathodes are investigated as alternative methods. In this work, the new cleaning procedures are tested and optimized, and the quantum efficiency of Mg samples with different microstructure, composition and suppliers are compared.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF039

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMF040

Experiences with the SRF Gun II for User Operation at the ELBE Radiation Source

4145

J. Teichert, A. Arnold, M. Bawatna, P.E. Evtushenko, M. Gensch, B.W. Green, S. Kovalev, U. Lehnert, P.N. Lu, P. Michel, P. Murcek, H. Vennekate, R. Xiang
HZDR, Dresden, Germany

Funding: The work is supported by the German Federal Ministry of Education and Research (BMBF) grant 05K12CR1.
The second version of the superconducting RF pho-toinjector (SRF Gun II) was successfully commissioned at the ELBE radiation source in 2014. The gun features an improved 3.5-cell niobium cavity combined with a super-conducting solenoid integrated in the cryostat. With a Mg photocathode the SRF Gun II is able to generate bunches with up to 200 pC and with sub-ps length in CW mode with 100 kHz pulse frequency for the THz radiation fa-cility at ELBE. In the ELBE linac, the beam is accelerat-ed, gets a proper correlated energy spread, and is com-pressed in a magnetic chicane. Sub-ps pulses are obtained producing coherent diffraction radiation and superradiant undulator radiation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF040

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)