IPAC2018 - List of Authors (Olexa, J.)

Paper	Title	Page
MOPMF047	Transverse Coupling Measurements With High Intensity Beams Using Driven Oscillations	208
	T. Persson, G. Baud, X. Buffat, J.M. Coello de Portugal, E. Fol, K. Fuchsberger, M. Gabriel, M. Gąsior, M. Giovannozzi, G.H. Hemelsoet, M. Hostettler, M. Hruska, D. Jacquet, E.H. Maclean, L. Malina, J. Olexa, P.K. Skowroński, M. Solfaroli Camillocci, M.E. Söderén, R. Tomás, D. Valuch, A. Wegscheider, J. Wenninger CERN, Geneva, Switzerland
	Transverse coupling has been linked to instabilities and reduction in dynamic aperture and is hence a crucial parameter to control in the LHC. In this article we describe the development to use driven oscillations to measure the transverse coupling with high intensity beams. The method relies on the use of the transverse damper to drive an oscillation in a similar way as with an AC-dipole. The calculation of the coupling is based on the turn-by-turn data from all available BPMs gated for the excited bunch.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF047
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPAF080	Beam Size Measurements Based on Movable Quadrupolar Pick-ups	2028
	A. Sounas, M. Gąsior, T. Lefèvre, A. Mereghetti, J. Olexa, S. Redaelli, G. Valentino CERN, Geneva, Switzerland
	Measurements with quadrupolar pick-ups (PU) have attracted particular interest as non-intercepting diagnostics for determining the transverse beam size. They are based on processing the signals of an electromagnetic PU for the extraction of the second-order moment, which contains information about the beam size. Despite the simplicity of the concept, quadrupololar measurements have always been highly challenging in reality. This comes from the fact that the quadrupolar moment constitutes only a very small part of the total PU signal dominated by the intensity and the position signals. Therefore, the beam size information can easily be lost due to small imperfections in the signal processing chain, such as asymmetries in the electronics and cables. In this paper, we present a new method for quadrupolar measurements using movable PUs. Through position and aperture scans, our technique minimizes the parasitic beam position signal and takes into account imperfections of the PU, cables and electronics, thus enabling an efficient auto-calibration of the measurement system. Preliminary studies, using collimators with embedded electrostatic PUs in the LHC at CERN, have shown very promising results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF080
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Transverse Coupling Measurements With High Intensity Beams Using Driven Oscillations

208

T. Persson, G. Baud, X. Buffat, J.M. Coello de Portugal, E. Fol, K. Fuchsberger, M. Gabriel, M. Gąsior, M. Giovannozzi, G.H. Hemelsoet, M. Hostettler, M. Hruska, D. Jacquet, E.H. Maclean, L. Malina, J. Olexa, P.K. Skowroński, M. Solfaroli Camillocci, M.E. Söderén, R. Tomás, D. Valuch, A. Wegscheider, J. Wenninger
CERN, Geneva, Switzerland

Transverse coupling has been linked to instabilities and reduction in dynamic aperture and is hence a crucial parameter to control in the LHC. In this article we describe the development to use driven oscillations to measure the transverse coupling with high intensity beams. The method relies on the use of the transverse damper to drive an oscillation in a similar way as with an AC-dipole. The calculation of the coupling is based on the turn-by-turn data from all available BPMs gated for the excited bunch.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF047

Export •

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

WEPAF080

Beam Size Measurements Based on Movable Quadrupolar Pick-ups

2028

A. Sounas, M. Gąsior, T. Lefèvre, A. Mereghetti, J. Olexa, S. Redaelli, G. Valentino
CERN, Geneva, Switzerland

Measurements with quadrupolar pick-ups (PU) have attracted particular interest as non-intercepting diagnostics for determining the transverse beam size. They are based on processing the signals of an electromagnetic PU for the extraction of the second-order moment, which contains information about the beam size. Despite the simplicity of the concept, quadrupololar measurements have always been highly challenging in reality. This comes from the fact that the quadrupolar moment constitutes only a very small part of the total PU signal dominated by the intensity and the position signals. Therefore, the beam size information can easily be lost due to small imperfections in the signal processing chain, such as asymmetries in the electronics and cables. In this paper, we present a new method for quadrupolar measurements using movable PUs. Through position and aperture scans, our technique minimizes the parasitic beam position signal and takes into account imperfections of the PU, cables and electronics, thus enabling an efficient auto-calibration of the measurement system. Preliminary studies, using collimators with embedded electrostatic PUs in the LHC at CERN, have shown very promising results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF080

Export •

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