IPAC2013 - List of Authors (Baer, T.)

Paper	Title	Page
MOPWO010	Machine Protection Studies for a Crab Cavity in the LHC	906
	B. Yee-Rendon, R. Lopez-Fernandez CINVESTAV, Mexico City, Mexico T. Baer, J. Barranco, R. Calaga, A. Marsili, R. Tomás, F. Zimmermann CERN, Geneva, Switzerland
	Funding: US-LARP and CONACYT Crab cavities (CCs) apply a transverse kick that rotate the bunches so as to have a head-on collision at the interaction point (IP). Such cavities were successfully used to improve the luminosity of KEKB. They are also a key ingredient of the HL-LHC project to increase the luminosity of the LHC. As CCs can rapidly change the particle trajectories, machine protection studies are required to assess the beam losses due to fast CC failures. In this paper, we discuss the effect of rapid voltage or phase changes in a CC for the HL-LHC layout using measured beam distributions from the present LHC.

WEPME044	Generation of Controlled Losses in Milisecond Timescale with Transverse Damper in LHC	3025
	M. Sapinski, T. Baer, V. Chetvertkova, B. Dehning, W. Höfle, A. Priebe, R. Schmidt, D. Valuch CERN, Geneva, Switzerland
	A controlled way of generating of beam losses is required in order to investigate the quench limits of the superconducting magnets in the LHC. This is especially difficult to achieve for losses with millisecond duration. A series of experiments using the transverse damper system has proven that such a fast loss can be obtained even in the case of rigid 4 TeV beams. This paper describes the optimisation of beam parameters and transverse damper waveform required to mimic fast loss scenarios and reports on extensive tracking simulations undertaken to fully understand the time and spatial structure of these losses. The application of this method to the final quench tests is also presented.

THPEA045	Beam Induced Quenches of LHC Magnets	3243
	M. Sapinski, T. Baer, M. Bednarek, G. Bellodi, C. Bracco, R. Bruce, B. Dehning, W. Höfle, A. Lechner, E. Nebot Del Busto, A. Priebe, S. Redaelli, B. Salvachua, R. Schmidt, D. Valuch, A.P. Verweij, J. Wenninger, D. Wollmann, M. Zerlauth CERN, Geneva, Switzerland
	In the years 2009-2013 LHC was operating with the beam energy of 3.5 and 4 TeV instead of the nominal 7 TeV, with the corresponding currents in the superconducting magnets also half nominal. To date only a small number of beam-induced quenches have occurred, with most being due to specially designed quench tests. During normal collider operation with stored beam there has not been a single beam induced quench. This excellent result is mainly explained by the fact that the cleaning of the beam halo worked very well and, in case of beam losses, the beam was dumped before any significant energy was deposited in the magnets. However, conditions are expected to become much tougher after the long LHC shutdown, when the magnets will be working at near nominal currents in the presence of high energy and intensity beams. This paper summarizes the experience to date with beam-induced quenches. It describes the techniques used to generate controlled quench conditions which were used to study the limitations. Results are discussed along with their implication for LHC operation after the first Long Shutdown.

Paper

Title

Page

Machine Protection Studies for a Crab Cavity in the LHC

906

B. Yee-Rendon, R. Lopez-Fernandez
CINVESTAV, Mexico City, Mexico
T. Baer, J. Barranco, R. Calaga, A. Marsili, R. Tomás, F. Zimmermann
CERN, Geneva, Switzerland

Funding: US-LARP and CONACYT
Crab cavities (CCs) apply a transverse kick that rotate the bunches so as to have a head-on collision at the interaction point (IP). Such cavities were successfully used to improve the luminosity of KEKB. They are also a key ingredient of the HL-LHC project to increase the luminosity of the LHC. As CCs can rapidly change the particle trajectories, machine protection studies are required to assess the beam losses due to fast CC failures. In this paper, we discuss the effect of rapid voltage or phase changes in a CC for the HL-LHC layout using measured beam distributions from the present LHC.

WEPME044

Generation of Controlled Losses in Milisecond Timescale with Transverse Damper in LHC

3025

M. Sapinski, T. Baer, V. Chetvertkova, B. Dehning, W. Höfle, A. Priebe, R. Schmidt, D. Valuch
CERN, Geneva, Switzerland

A controlled way of generating of beam losses is required in order to investigate the quench limits of the superconducting magnets in the LHC. This is especially difficult to achieve for losses with millisecond duration. A series of experiments using the transverse damper system has proven that such a fast loss can be obtained even in the case of rigid 4 TeV beams. This paper describes the optimisation of beam parameters and transverse damper waveform required to mimic fast loss scenarios and reports on extensive tracking simulations undertaken to fully understand the time and spatial structure of these losses. The application of this method to the final quench tests is also presented.

THPEA045

Beam Induced Quenches of LHC Magnets

3243

M. Sapinski, T. Baer, M. Bednarek, G. Bellodi, C. Bracco, R. Bruce, B. Dehning, W. Höfle, A. Lechner, E. Nebot Del Busto, A. Priebe, S. Redaelli, B. Salvachua, R. Schmidt, D. Valuch, A.P. Verweij, J. Wenninger, D. Wollmann, M. Zerlauth
CERN, Geneva, Switzerland

In the years 2009-2013 LHC was operating with the beam energy of 3.5 and 4 TeV instead of the nominal 7 TeV, with the corresponding currents in the superconducting magnets also half nominal. To date only a small number of beam-induced quenches have occurred, with most being due to specially designed quench tests. During normal collider operation with stored beam there has not been a single beam induced quench. This excellent result is mainly explained by the fact that the cleaning of the beam halo worked very well and, in case of beam losses, the beam was dumped before any significant energy was deposited in the magnets. However, conditions are expected to become much tougher after the long LHC shutdown, when the magnets will be working at near nominal currents in the presence of high energy and intensity beams. This paper summarizes the experience to date with beam-induced quenches. It describes the techniques used to generate controlled quench conditions which were used to study the limitations. Results are discussed along with their implication for LHC operation after the first Long Shutdown.