IPAC2015 - List of Authors (Kugeler, O.)

Paper	Title	Page
TUPWA018	Progress Report of the Berlin Energy Recovery Project BERLinPro	1438
	M. Abo-Bakr, W. Anders, K.B. Bürkmann-Gehrlein, A. Burrill, A.B. Büchel, P. Echevarria, A. Frahm, H.-W. Glock, A. Jankowiak, C. Kalus, T. Kamps, G. Klemz, J. Knobloch, J. Kolbe, J. Kühn, O. Kugeler, B.C. Kuske, P. Kuske, A.N. Matveenko, A. Meseck, R. Müller, A. Neumann, N. Ohm, K. Ott, E. Panofski, F. Pflocksch, D. Pflückhahn, J. Rahn, J. Rudolph, M. Schmeißer, O. Schüler, J. Völker HZB, Berlin, Germany
	Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association The Helmholtz Zentrum Berlin is constructing the Energy Recovery Linac Project BERLinPro on its site in Berlin Adlershof. The project is intended to expand the required accelerator physics and technology knowledge mandatory for the design, construction and operation of future synchrotron light sources. The project goal is the generation of a high current (100 mA), high brilliance (norm. emittance below 1 mm mrad) cw electron beamat 2~ps rms bunch duration or below. The planning phase of the project is completed and the design phase of most of the components is finished. Many of them have already been ordered. After some delay the construction of the building has started in February 2015. The status of the various subprojects as well as a summary of current and future activities will be given. Major project milestones and details of the project time line will be finally introduced.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA018
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WEPMA012	High-Q Cavity Operation: Study on the Thermoelectrically Induced Contribution to RF Surface Resistance	2771
	J.M. Köszegi, J. Knobloch, O. Kugeler, A. Neumann, A.V. Vélez HZB, Berlin, Germany
	We present a study concerning the operation of a superconducting RF cavity (non-doped niobium) in horizontal testing with the focus on understanding the thermoelectrically induced contribution to the surface resistance. Starting in 2009, we suggested a means of reducing the residual resistance by warming up a cavity after initial cooldown to about 20K and cooling it down again. In subsequent studies we used this technique to manipulate the residual resistance by more than a factor of 2. We postulated that thermocurrents during cooldown generate additional trapped magnetic flux that impacts the cavity quality factor. Since several questions remained open, we present here a more extensive study including measurement of two additional passband modes of the 9-cell cavity that confirms the effect. We also discuss simulations that substantiate the claim. While the layout of the cavity LHe tank system is cylindrically symmetric, we show that the temperature dependence of the material parameters result in a non-symmetric current distribution. Hence a significant amount of magnetic flux can be generated at the RF surface resulting in an increased surface resistance.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMA012
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Progress Report of the Berlin Energy Recovery Project BERLinPro

1438

M. Abo-Bakr, W. Anders, K.B. Bürkmann-Gehrlein, A. Burrill, A.B. Büchel, P. Echevarria, A. Frahm, H.-W. Glock, A. Jankowiak, C. Kalus, T. Kamps, G. Klemz, J. Knobloch, J. Kolbe, J. Kühn, O. Kugeler, B.C. Kuske, P. Kuske, A.N. Matveenko, A. Meseck, R. Müller, A. Neumann, N. Ohm, K. Ott, E. Panofski, F. Pflocksch, D. Pflückhahn, J. Rahn, J. Rudolph, M. Schmeißer, O. Schüler, J. Völker
HZB, Berlin, Germany

Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association
The Helmholtz Zentrum Berlin is constructing the Energy Recovery Linac Project BERLinPro on its site in Berlin Adlershof. The project is intended to expand the required accelerator physics and technology knowledge mandatory for the design, construction and operation of future synchrotron light sources. The project goal is the generation of a high current (100 mA), high brilliance (norm. emittance below 1 mm mrad) cw electron beamat 2~ps rms bunch duration or below. The planning phase of the project is completed and the design phase of most of the components is finished. Many of them have already been ordered. After some delay the construction of the building has started in February 2015. The status of the various subprojects as well as a summary of current and future activities will be given. Major project milestones and details of the project time line will be finally introduced.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA018

Export •

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

WEPMA012

High-Q Cavity Operation: Study on the Thermoelectrically Induced Contribution to RF Surface Resistance

2771

J.M. Köszegi, J. Knobloch, O. Kugeler, A. Neumann, A.V. Vélez
HZB, Berlin, Germany

We present a study concerning the operation of a superconducting RF cavity (non-doped niobium) in horizontal testing with the focus on understanding the thermoelectrically induced contribution to the surface resistance. Starting in 2009, we suggested a means of reducing the residual resistance by warming up a cavity after initial cooldown to about 20K and cooling it down again. In subsequent studies we used this technique to manipulate the residual resistance by more than a factor of 2. We postulated that thermocurrents during cooldown generate additional trapped magnetic flux that impacts the cavity quality factor. Since several questions remained open, we present here a more extensive study including measurement of two additional passband modes of the 9-cell cavity that confirms the effect. We also discuss simulations that substantiate the claim. While the layout of the cavity LHe tank system is cylindrically symmetric, we show that the temperature dependence of the material parameters result in a non-symmetric current distribution. Hence a significant amount of magnetic flux can be generated at the RF surface resulting in an increased surface resistance.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMA012

Export •

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