IPAC2022 - List of Authors (Ravaioli, E.)

Paper	Title	Page
MOPOPT040	Summary of the Post-Long Shutdown 2 LHC Hardware Commissioning Campaign	335
	A. Apollonio, O.Ø. Andreassen, A. Antoine, T. Argyropoulos, M.C. Bastos, M. Bednarek, B. Bordini, K. Brodzinski, A. Calia, Z. Charifoulline, G.-J. Coelingh, G. D’Angelo, D. Delikaris, R. Denz, L. Fiscarelli, V. Froidbise, M.A. Galilée, J.C. Garnier, R. Gorbonosov, P. Hagen, M. Hostettler, D. Jacquet, S. Le Naour, D. Mirarchi, V. Montabonnet, B.I. Panev, T.H.B. Persson, T. Podzorny, M. Pojer, E. Ravaioli, F. Rodriguez-Mateos, A.P. Siemko, M. Solfaroli, J. Spasic, A. Stanisz, J. Steckert, R. Steerenberg, S. Sudak, H. Thiesen, E. Todesco, G. Trad, J.A. Uythoven, S. Uznanski, A.P. Verweij, J. Wenninger, G.P. Willering, D. Wollmann, S. Yammine CERN, Meyrin, Switzerland V. Vizziello INFN/LASA, Segrate (MI), Italy
	In this contribution we provide a summary of the LHC hardware commissioning campaign following the second CERN Long Shutdown (LS2), initially targeting the nominal LHC energy of 7 TeV. A summary of the test procedures and tools used for testing the LHC superconducting circuits is given, together with statistics on the successful test execution. The paper then focuses on the experience and observations during the main dipole training campaign, describing the encountered problems, the related analysis and mitigation measures, ultimately leading to the decision to reduce the energy target to 6.8 TeV. The re-commissioning of two powering sectors, following the identified problems, is discussed in detail. The paper concludes with an outlook to the future hardware commissioning campaigns, discussing the lessons learnt and possible strategies moving forward.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT040
About •	Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 27 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOPT013	Effect of a Spurious CLIQ Firing on the Circulating Beam in HL-LHC	1862
	C. Hernalsteens, B. Lindström, E. Ravaioli, O.K. Tuormaa, M. Villén Basco, C. Wiesner, D. Wollmann CERN, Meyrin, Switzerland
	The High Luminosity LHC (HL-LHC) will reach a nominal, levelled luminosity of §I{5e34}{\per\cm\square\per\second} and a stored energy of nearly §I{700}{MJ} in each of the two proton beams. The new large-aperture final focusing Nb₃Sn quadrupole magnets in IR1 and IR5, which are essential to achieve the luminosity target, will be protected using the novel Coupling Loss Induced Quench (CLIQ) system. A spurious discharge of a CLIQ unit will impact the circulating beam through higher order multipolar field components that develop rapidly over a few turns. This paper reports on dedicated beam tracking studies performed to evaluate the criticality of this failure on the HL-LHC beam. Simulations for different machine and optics configurations show that the beam losses reach a critical level after only five machine turns following the spurious CLIQ trigger, which is much faster than assumed in previous simulations that did not consider the higher order multipolar fields. Machine protection requirements using a dedicated interlock to mitigate this failure are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT013
About •	Received ※ 08 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 01 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOPT016	Beam-Based Reconstruction of the Shielded Quench-Heater Fields for the LHC Main Dipoles	1874
	L.C. Richtmann, L. Bortot, E. Ravaioli, C. Wiesner, D. Wollmann CERN, Meyrin, Switzerland
	Small orbit oscillations of the circulating particle beams have been observed immediately following quenches in the LHC’s superconducting main dipole magnets. Magnetic fields generated during the discharge into the quench heaters were identified as the cause. Since the resulting, shielded field inside the beam screen cannot be measured in-situ, the time evolution of the field has to be reconstructed from the measured beam excursions. In this paper, the field-reconstruction method using rotation in normalized phase space and the optimized fitting algorithm are described. The resulting rise times and magnetic field levels are presented for quench events that occurred during regular operation as well as for dedicated beam experiments. Finally, different approaches to model the shielding behavior of the beam screen are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT016
About •	Received ※ 16 May 2022 — Accepted ※ 13 June 2022 — Issue date ※ 26 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Summary of the Post-Long Shutdown 2 LHC Hardware Commissioning Campaign

335

A. Apollonio, O.Ø. Andreassen, A. Antoine, T. Argyropoulos, M.C. Bastos, M. Bednarek, B. Bordini, K. Brodzinski, A. Calia, Z. Charifoulline, G.-J. Coelingh, G. D’Angelo, D. Delikaris, R. Denz, L. Fiscarelli, V. Froidbise, M.A. Galilée, J.C. Garnier, R. Gorbonosov, P. Hagen, M. Hostettler, D. Jacquet, S. Le Naour, D. Mirarchi, V. Montabonnet, B.I. Panev, T.H.B. Persson, T. Podzorny, M. Pojer, E. Ravaioli, F. Rodriguez-Mateos, A.P. Siemko, M. Solfaroli, J. Spasic, A. Stanisz, J. Steckert, R. Steerenberg, S. Sudak, H. Thiesen, E. Todesco, G. Trad, J.A. Uythoven, S. Uznanski, A.P. Verweij, J. Wenninger, G.P. Willering, D. Wollmann, S. Yammine
CERN, Meyrin, Switzerland
V. Vizziello
INFN/LASA, Segrate (MI), Italy

In this contribution we provide a summary of the LHC hardware commissioning campaign following the second CERN Long Shutdown (LS2), initially targeting the nominal LHC energy of 7 TeV. A summary of the test procedures and tools used for testing the LHC superconducting circuits is given, together with statistics on the successful test execution. The paper then focuses on the experience and observations during the main dipole training campaign, describing the encountered problems, the related analysis and mitigation measures, ultimately leading to the decision to reduce the energy target to 6.8 TeV. The re-commissioning of two powering sectors, following the identified problems, is discussed in detail. The paper concludes with an outlook to the future hardware commissioning campaigns, discussing the lessons learnt and possible strategies moving forward.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT040

About •

Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 27 June 2022

Cite •

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

WEPOPT013

Effect of a Spurious CLIQ Firing on the Circulating Beam in HL-LHC

1862

C. Hernalsteens, B. Lindström, E. Ravaioli, O.K. Tuormaa, M. Villén Basco, C. Wiesner, D. Wollmann
CERN, Meyrin, Switzerland

The High Luminosity LHC (HL-LHC) will reach a nominal, levelled luminosity of §I{5e34}{\per\cm\square\per\second} and a stored energy of nearly §I{700}{MJ} in each of the two proton beams. The new large-aperture final focusing Nb₃Sn quadrupole magnets in IR1 and IR5, which are essential to achieve the luminosity target, will be protected using the novel Coupling Loss Induced Quench (CLIQ) system. A spurious discharge of a CLIQ unit will impact the circulating beam through higher order multipolar field components that develop rapidly over a few turns. This paper reports on dedicated beam tracking studies performed to evaluate the criticality of this failure on the HL-LHC beam. Simulations for different machine and optics configurations show that the beam losses reach a critical level after only five machine turns following the spurious CLIQ trigger, which is much faster than assumed in previous simulations that did not consider the higher order multipolar fields. Machine protection requirements using a dedicated interlock to mitigate this failure are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT013

About •

Received ※ 08 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 01 July 2022

Cite •

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

WEPOPT016

Beam-Based Reconstruction of the Shielded Quench-Heater Fields for the LHC Main Dipoles

1874

L.C. Richtmann, L. Bortot, E. Ravaioli, C. Wiesner, D. Wollmann
CERN, Meyrin, Switzerland

Small orbit oscillations of the circulating particle beams have been observed immediately following quenches in the LHC’s superconducting main dipole magnets. Magnetic fields generated during the discharge into the quench heaters were identified as the cause. Since the resulting, shielded field inside the beam screen cannot be measured in-situ, the time evolution of the field has to be reconstructed from the measured beam excursions. In this paper, the field-reconstruction method using rotation in normalized phase space and the optimized fitting algorithm are described. The resulting rise times and magnetic field levels are presented for quench events that occurred during regular operation as well as for dedicated beam experiments. Finally, different approaches to model the shielding behavior of the beam screen are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT016

About •

Received ※ 16 May 2022 — Accepted ※ 13 June 2022 — Issue date ※ 26 June 2022

Cite •

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