IPAC2015 - List of Authors (Bartosik, H.)

Paper	Title	Page
MOPJE027	Beam-based Impedance Characterization of the ALBA Pinger Magnet	334
	U. Iriso, T.F.G. Günzel ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain H. Bartosik, E. Koukovini-Platia, G. Rumolo CERN, Geneva, Switzerland
	The ALBA pinger magnet consists on two short kickers (for horizontal and vertical planes) installed in a single Titanium coated ceramic vacuum chamber. Single bunch measurements in the vertical plane were performed in the ALBA Synchrotron Light Source before and after the pinger installation, and by comparing the Transverse Mode Coupling Instability (TMCI) thresholds for zero chromaticity, we infer the pinger impedance and compare it with the model predictions. We also perform measurements for negative chromaticities and results are reported in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE027
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MOPJE049	Benchmarking the CERN-SPS Transverse Impedance Model with Measured Headtail Growth Rates	402
	C. Zannini, H. Bartosik, G. Iadarola, G. Rumolo, B. Salvant CERN, Geneva, Switzerland
	The latest SPS transverse impedance model includes kicker magnets, wall impedance, transition pieces (e.g. flanges and vacuum chamber discontinuities), beam position monitors and RF cavities. The model has already been successfully benchmarked against coherent tune shift and transverse mode coupling instability measurements. In this paper we present measurements of the headtail growth rates for a wide range of negative chromaticities and for two different configurations of machine optics (nominal and low gamma transition). The measurement results are compared with HEADTAIL simulations using the wake fields obtained from the SPS transverse impedance model.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE049
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MOPJE051	Effect of Electron Cloud in Quadrupoles on Beam Instability	409
	G. Iadarola, A.P. Axford, H. Bartosik, K.S.B. Li, G. Rumolo CERN, Geneva, Switzerland
	Both simulations and machine experience at the CERN-SPS and LHC have shown that the electron cloud has a lower build up threshold in quadrupoles than in dipoles and field free regions. As a consequence, while beam induced scrubbing can efficiently suppress the electron cloud in both dipoles and field free regions, a residual electron cloud can still survive in the quadrupoles and potentially degrade the beam quality. To study this effect, a PyECLOUD module for electron tracking in quadrupole fields including effects of secondary emission at the vacuum chamber has been implemented in PyHEADTAIL. With this module, the effect of the electron cloud in quadrupoles on beam stability and beam quality preservation can be assessed, as well as its impact on future LHC and HL-LHC operation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE051
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THPF091	Detailed Studies of Beam Induced Scrubbing in the CERN-SPS	3908
	G. Iadarola, H. Bartosik, T. Bohl, B. Goddard, G. Kotzian, K.S.B. Li, L. Mether, G. Rumolo, M. Schenk, E.N. Shaposhnikova, M. Taborelli CERN, Geneva, Switzerland
	In the framework of the LHC Injectors Upgrade (LIU) program, it is foreseen to take all the necessary measures to avoid electron cloud effects in the CERN-SPS. This can be achieved by either relying on beam induced scrubbing or by coating the vacuum chambers with intrinsically low Secondary Electron Yield (SEY) material over a large fraction of the ring. To clearly establish the potential of beam induced scrubbing, and to eventually decide between the two above options, an extensive scrubbing campaign is taking place at the SPS. Ten days in 2014 and two full weeks in 2015 are devoted to machine scrubbing and scrubbing qualification studies. This paper summarizes the main findings in terms of scrubbing efficiency and reach so far, addressing also the option of using a special doublet beam and its implication for LHC.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF091
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Paper

Title

Page

Beam-based Impedance Characterization of the ALBA Pinger Magnet

334

U. Iriso, T.F.G. Günzel
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
H. Bartosik, E. Koukovini-Platia, G. Rumolo
CERN, Geneva, Switzerland

The ALBA pinger magnet consists on two short kickers (for horizontal and vertical planes) installed in a single Titanium coated ceramic vacuum chamber. Single bunch measurements in the vertical plane were performed in the ALBA Synchrotron Light Source before and after the pinger installation, and by comparing the Transverse Mode Coupling Instability (TMCI) thresholds for zero chromaticity, we infer the pinger impedance and compare it with the model predictions. We also perform measurements for negative chromaticities and results are reported in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE027

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

MOPJE049

Benchmarking the CERN-SPS Transverse Impedance Model with Measured Headtail Growth Rates

402

C. Zannini, H. Bartosik, G. Iadarola, G. Rumolo, B. Salvant
CERN, Geneva, Switzerland

The latest SPS transverse impedance model includes kicker magnets, wall impedance, transition pieces (e.g. flanges and vacuum chamber discontinuities), beam position monitors and RF cavities. The model has already been successfully benchmarked against coherent tune shift and transverse mode coupling instability measurements. In this paper we present measurements of the headtail growth rates for a wide range of negative chromaticities and for two different configurations of machine optics (nominal and low gamma transition). The measurement results are compared with HEADTAIL simulations using the wake fields obtained from the SPS transverse impedance model.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE049

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

MOPJE051

Effect of Electron Cloud in Quadrupoles on Beam Instability

409

G. Iadarola, A.P. Axford, H. Bartosik, K.S.B. Li, G. Rumolo
CERN, Geneva, Switzerland

Both simulations and machine experience at the CERN-SPS and LHC have shown that the electron cloud has a lower build up threshold in quadrupoles than in dipoles and field free regions. As a consequence, while beam induced scrubbing can efficiently suppress the electron cloud in both dipoles and field free regions, a residual electron cloud can still survive in the quadrupoles and potentially degrade the beam quality. To study this effect, a PyECLOUD module for electron tracking in quadrupole fields including effects of secondary emission at the vacuum chamber has been implemented in PyHEADTAIL. With this module, the effect of the electron cloud in quadrupoles on beam stability and beam quality preservation can be assessed, as well as its impact on future LHC and HL-LHC operation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE051

Export •

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

THPF091

Detailed Studies of Beam Induced Scrubbing in the CERN-SPS

3908

G. Iadarola, H. Bartosik, T. Bohl, B. Goddard, G. Kotzian, K.S.B. Li, L. Mether, G. Rumolo, M. Schenk, E.N. Shaposhnikova, M. Taborelli
CERN, Geneva, Switzerland

In the framework of the LHC Injectors Upgrade (LIU) program, it is foreseen to take all the necessary measures to avoid electron cloud effects in the CERN-SPS. This can be achieved by either relying on beam induced scrubbing or by coating the vacuum chambers with intrinsically low Secondary Electron Yield (SEY) material over a large fraction of the ring. To clearly establish the potential of beam induced scrubbing, and to eventually decide between the two above options, an extensive scrubbing campaign is taking place at the SPS. Ten days in 2014 and two full weeks in 2015 are devoted to machine scrubbing and scrubbing qualification studies. This paper summarizes the main findings in terms of scrubbing efficiency and reach so far, addressing also the option of using a special doublet beam and its implication for LHC.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF091

Export •

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