IPAC2018 - List of Authors (Hostettler, M.)

Paper	Title	Page
MOPMF040	Crossing Angle Anti-Leveling at the LHC in 2017	184
	N. Karastathis, K. Fuchsberger, M. Hostettler, Y. Papaphilippou, D. Pellegrini CERN, Geneva, Switzerland
	In 2017, LHC incorporated in operation an anti-leveling procedure of adapting in steps the crossing angle of the colliding beams to increase the integrated luminosity. In this paper, we present the Dynamic Aperture simulations that were employed to identify the operational margins, and therefore define the leveling steps. The results are complemented by observations from nominal operation and projections for the 2018 operation. Additional anti-leveling techniques, investigated in dedicated machine studies are also discussed
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF040
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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)

MOPMF050	LHC Operational Experience of the 6.5 TeV Proton Run with ATS Optics	216
	M. Pojer, M. Albert, R. Alemany-Fernández, T. Argyropoulos, E. Bravin, A. Calia, G.E. Crockford, S.D. Fartoukh, K. Fuchsberger, R. Giachino, M. Giovannozzi, G.H. Hemelsoet, M. Hostettler, W. Höfle, Y. Le Borgne, D. Nisbet, L. Ponce, S. Redaelli, B. Salvachua, M. Solfaroli, R. Suykerbuyk, D.J. Walsh, J. Wenninger, M. Zerlauth CERN, Geneva, Switzerland
	In May 2017, the CERN Large Hadron Collider (LHC) restarted operations at 6.5 TeV using the Achromatic Telescopic Squeeze (ATS) scheme with a target beta-star of 40 cm in ATLAS and CMS. The number of bunches was progressively increased to a maximum of 2556 with emittances of 2.5 um. In August, several machine parameters had to be re-tuned to mitigate beam loss induced instabilities and maintain a steady increase of the instantaneous luminosity. The use of a novel beam type and filling pattern produced in the injectors, allowed filling the machine with very low emittance beam (1.5 um) achieving an equivalent luminosity with 1868 bunches. In September, the beta-star was further lowered to 30 cm (using, for the first time, the telescopic technique of the ATS) and the bunch intensity pushed to 1.25·10¹¹ protons. In the last 3 months of 2017, the LHC produced more than 500 pb-1 of integrated luminosity per day, delivering to each of the high luminosity experiments 50.6 fb-1, 10% above the 2017 target. A general overview of the operational aspects of the 2017 proton run will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF050
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MOPMF052	Monitoring and Modeling of the LHC Luminosity Evolution in 2017	224
	N. Karastathis, F. Antoniou, I. Efthymiopoulos, M. Hostettler, G. Iadarola, S. Papadopoulou, Y. Papaphilippou, D. Pellegrini, B. Salvachua CERN, Geneva, Switzerland
	In 2017, the Large Hadron Collider (LHC) restarted operation at 6.5 TeV, after an extended end-of-the-year stop, scheduled to deliver 45/fb to the two general-purpose experiments. Continuous monitoring of the key beam parameters and machine configurations that impact the delivered luminosity was introduced, providing fast feedback to operations for further optimisation. The numerical model based on simulations and use of selected machine parameters to estimate the machine luminosity was further developed. The luminosity evolution and comparisons to the model predictions is presented in this paper. The impact of the dynamic variation of the crossing angle, which was incorporated into nominal LHC operation, is also discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF052
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Crossing Angle Anti-Leveling at the LHC in 2017

184

N. Karastathis, K. Fuchsberger, M. Hostettler, Y. Papaphilippou, D. Pellegrini
CERN, Geneva, Switzerland

In 2017, LHC incorporated in operation an anti-leveling procedure of adapting in steps the crossing angle of the colliding beams to increase the integrated luminosity. In this paper, we present the Dynamic Aperture simulations that were employed to identify the operational margins, and therefore define the leveling steps. The results are complemented by observations from nominal operation and projections for the 2018 operation. Additional anti-leveling techniques, investigated in dedicated machine studies are also discussed

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF040

Export •

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

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)

MOPMF050

LHC Operational Experience of the 6.5 TeV Proton Run with ATS Optics

216

M. Pojer, M. Albert, R. Alemany-Fernández, T. Argyropoulos, E. Bravin, A. Calia, G.E. Crockford, S.D. Fartoukh, K. Fuchsberger, R. Giachino, M. Giovannozzi, G.H. Hemelsoet, M. Hostettler, W. Höfle, Y. Le Borgne, D. Nisbet, L. Ponce, S. Redaelli, B. Salvachua, M. Solfaroli, R. Suykerbuyk, D.J. Walsh, J. Wenninger, M. Zerlauth
CERN, Geneva, Switzerland

In May 2017, the CERN Large Hadron Collider (LHC) restarted operations at 6.5 TeV using the Achromatic Telescopic Squeeze (ATS) scheme with a target beta-star of 40 cm in ATLAS and CMS. The number of bunches was progressively increased to a maximum of 2556 with emittances of 2.5 um. In August, several machine parameters had to be re-tuned to mitigate beam loss induced instabilities and maintain a steady increase of the instantaneous luminosity. The use of a novel beam type and filling pattern produced in the injectors, allowed filling the machine with very low emittance beam (1.5 um) achieving an equivalent luminosity with 1868 bunches. In September, the beta-star was further lowered to 30 cm (using, for the first time, the telescopic technique of the ATS) and the bunch intensity pushed to 1.25·10¹¹ protons. In the last 3 months of 2017, the LHC produced more than 500 pb-1 of integrated luminosity per day, delivering to each of the high luminosity experiments 50.6 fb-1, 10% above the 2017 target. A general overview of the operational aspects of the 2017 proton run will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF050

Export •

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

MOPMF052

Monitoring and Modeling of the LHC Luminosity Evolution in 2017

224

N. Karastathis, F. Antoniou, I. Efthymiopoulos, M. Hostettler, G. Iadarola, S. Papadopoulou, Y. Papaphilippou, D. Pellegrini, B. Salvachua
CERN, Geneva, Switzerland

In 2017, the Large Hadron Collider (LHC) restarted operation at 6.5 TeV, after an extended end-of-the-year stop, scheduled to deliver 45/fb to the two general-purpose experiments. Continuous monitoring of the key beam parameters and machine configurations that impact the delivered luminosity was introduced, providing fast feedback to operations for further optimisation. The numerical model based on simulations and use of selected machine parameters to estimate the machine luminosity was further developed. The luminosity evolution and comparisons to the model predictions is presented in this paper. The impact of the dynamic variation of the crossing angle, which was incorporated into nominal LHC operation, is also discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF052

Export •

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