IPAC2014 - List of Authors (Ruprecht, M.)

Paper	Title	Page
MOPRO058	The Low-alpha Lattice and Bunch Length Limits at BESSY-VSR	216
	P. Goslawski, M. Ries, M. Ruprecht, G. Wüstefeld HZB, Berlin, Germany
	Funding: Work supported by German Bundesministerium für Bildung und Forschung and Land Berlin. An upgrade of the BESSY II ring to a Variable bunch length Storage Ring BESSY^VSR has been recently proposed , by introducing strongly focusing superconducting cavities. This will allow to store simultaneously long and short bunches. In the regular user optics, bunch lengths of 15 ps (rms) and down to 1.5 ps (rms) are expected. Bunches as short as 300 fs (rms), close to the bunch length limit, and a ring current of 3.5 mA at the bunch bursting threshold can be provided by using a modified low-alpha optics. This presentation will discuss the properties of the low-alpha optics and intrinsic bunch length limits, given by coupling effects of the longitudinal and horizontal plane. G. Wüstefeld, A. Jankowiak, J. Knobloch, M.Ries, "Simultaneous Long and Short Electron Bunches in the BESSYII Storage Ring", Proceedings of IPAC2011, San Sebastian, Spain.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO058
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI043	Analysis of Coupled Bunch Instabilities in BESSY-VSR	1659
	M. Ruprecht, P. Goslawski, A. Jankowiak, M. Ries, A. Schälicke, G. Wüstefeld HZB, Berlin, Germany T. Weis DELTA, Dortmund, Germany
	BESSY-VSR, a scheme where 1.5 ps and 15 ps long bunches (rms) can be stored simultaneously in the BESSY II storage ring has recently been proposed. The strong longitudinal bunch focusing is achieved by superconducting high gradient RF cavities. This paper presents investigations of coupled bunch instabilities driven by HOMs of superconducting multi cell cavities in BESSY-VSR. Analytical calculations and tracking simulations in time domain are performed in the longitudinal and the transverse planes and factors that influence the threshold currents are being discussed. Suitable candidates of cavities which are presently available or in the phase of design are compared with respect to their instability thresholds. G. Wüstefeld, A. Jankowiak, J. Knobloch, M. Ries, Simultaneous Long and Short Electron Bunches in the BESSY II Storage Ring, Proceedings of IPAC2011, San Sebastián, Spain
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI043
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI072	Status and Performance of Bunch-by-bunch Feedback at BESSY II and MLS	1733
	A. Schälicke, P. Goslawski, M. Ries, M. Ruprecht HZB, Berlin, Germany
	Funding: Work supported by German Bundesministerium für Bildung und Forschung and Land Berlin. Bunch-by-bunch feedback systems provide an important component in the reliable operation of electron storage rings. Modern digital bunch-by-bunch feedback systems allow efficient mitigation of multi-bunch instabilities, and at the same time offer valuable beam diagnostics. In this contribution, setup and performance of the bunch-by-bunch feedback systems at BESSY II and the MLS are presented. Longitudinal and transverse instabilities are studied under different machine conditions. The developed data analysis techniques and experimental measurements are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI072
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI008	First Cavity Design Studies for the BESSY-VSR Upgrade Proposal	2493
	A. Neumann, A. Burrill, P. Goslawski, A. Jankowiak, J. Knobloch, M. Ries, M. Ruprecht, A.V. Vélez, G. Wüstefeld HZB, Berlin, Germany
	Funding: Work supported by German Bundesministerium für Bildung und Forschung and Land Berlin Recently HZB proposed an upgrade of the 3rd generation synchrotron light source BESSY II allowing simultanous long and short pulse operation. For this scheme to work superconducting higher harmonic cavities of the fundamental 500 MHz at two frequencies need to be installed in the BESSY II storage ring. Given an appropiate choice of the higher harmonics the resulting gradient leads to a beating effect of the effective longitudinal focussing voltage at the stable fix points resulting in different bunch lengths in subsequent buckets. This project places stringent requirements on the cavity performance, as high accelerating fields, excellent HOM damping capabilities and high reliability as they will operate in a 300 mA 24/7 user facility. In this paper we describe the requirements for the cavity design and first designs steps. G. Wüstefeldt et al., Simultaneous Long and Short Electron Bunches in the BESSY II Storage Ring, Proc. of IPAC'11, San Sebástian, Spain
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI008
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

The Low-alpha Lattice and Bunch Length Limits at BESSY-VSR

216

P. Goslawski, M. Ries, M. Ruprecht, G. Wüstefeld
HZB, Berlin, Germany

Funding: Work supported by German Bundesministerium für Bildung und Forschung and Land Berlin.
An upgrade of the BESSY II ring to a Variable bunch length Storage Ring BESSY^VSR has been recently proposed *, by introducing strongly focusing superconducting cavities. This will allow to store simultaneously long and short bunches. In the regular user optics, bunch lengths of 15 ps (rms) and down to 1.5 ps (rms) are expected. Bunches as short as 300 fs (rms), close to the bunch length limit, and a ring current of 3.5 mA at the bunch bursting threshold can be provided by using a modified low-alpha optics. This presentation will discuss the properties of the low-alpha optics and intrinsic bunch length limits, given by coupling effects of the longitudinal and horizontal plane.
* G. Wüstefeld, A. Jankowiak, J. Knobloch, M.Ries, "Simultaneous Long and Short Electron Bunches in the BESSYII Storage Ring", Proceedings of IPAC2011, San Sebastian, Spain.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO058

Export •

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

TUPRI043

Analysis of Coupled Bunch Instabilities in BESSY-VSR

1659

M. Ruprecht, P. Goslawski, A. Jankowiak, M. Ries, A. Schälicke, G. Wüstefeld
HZB, Berlin, Germany
T. Weis
DELTA, Dortmund, Germany

BESSY-VSR, a scheme where 1.5 ps and 15 ps long bunches (rms) can be stored simultaneously in the BESSY II storage ring has recently been proposed*. The strong longitudinal bunch focusing is achieved by superconducting high gradient RF cavities. This paper presents investigations of coupled bunch instabilities driven by HOMs of superconducting multi cell cavities in BESSY-VSR. Analytical calculations and tracking simulations in time domain are performed in the longitudinal and the transverse planes and factors that influence the threshold currents are being discussed. Suitable candidates of cavities which are presently available or in the phase of design are compared with respect to their instability thresholds.
* G. Wüstefeld, A. Jankowiak, J. Knobloch, M. Ries, Simultaneous Long and Short Electron Bunches in the BESSY II Storage Ring, Proceedings of IPAC2011, San Sebastián, Spain

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI043

Export •

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

TUPRI072

Status and Performance of Bunch-by-bunch Feedback at BESSY II and MLS

1733

A. Schälicke, P. Goslawski, M. Ries, M. Ruprecht
HZB, Berlin, Germany

Funding: Work supported by German Bundesministerium für Bildung und Forschung and Land Berlin.
Bunch-by-bunch feedback systems provide an important component in the reliable operation of electron storage rings. Modern digital bunch-by-bunch feedback systems allow efficient mitigation of multi-bunch instabilities, and at the same time offer valuable beam diagnostics. In this contribution, setup and performance of the bunch-by-bunch feedback systems at BESSY II and the MLS are presented. Longitudinal and transverse instabilities are studied under different machine conditions. The developed data analysis techniques and experimental measurements are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI072

Export •

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

WEPRI008

First Cavity Design Studies for the BESSY-VSR Upgrade Proposal

2493

A. Neumann, A. Burrill, P. Goslawski, A. Jankowiak, J. Knobloch, M. Ries, M. Ruprecht, A.V. Vélez, G. Wüstefeld
HZB, Berlin, Germany

Funding: Work supported by German Bundesministerium für Bildung und Forschung and Land Berlin
Recently HZB proposed an upgrade of the 3rd generation synchrotron light source BESSY II allowing simultanous long and short pulse operation*. For this scheme to work superconducting higher harmonic cavities of the fundamental 500 MHz at two frequencies need to be installed in the BESSY II storage ring. Given an appropiate choice of the higher harmonics the resulting gradient leads to a beating effect of the effective longitudinal focussing voltage at the stable fix points resulting in different bunch lengths in subsequent buckets. This project places stringent requirements on the cavity performance, as high accelerating fields, excellent HOM damping capabilities and high reliability as they will operate in a 300 mA 24/7 user facility. In this paper we describe the requirements for the cavity design and first designs steps.
* G. Wüstefeldt et al., Simultaneous Long and Short Electron Bunches in the BESSY II Storage Ring, Proc. of IPAC'11, San Sebástian, Spain

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI008

Export •

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