HB2012 - List of Keywords (insertion)

Paper	Title	Other Keywords	Page
MOI1A01	LHC - Challenges in Handling Beams Exceeding 100 MJ	beam-losses, luminosity, collimation, injection	1
	R. Schmidt CERN, Geneva, Switzerland
	The Large Hadron Collider (LHC) at CERN operates at 4 TeV with high intensity beams, with bunch intensities exceeding the nominal value by several 10 %. The energy stored in each beams is beyond 130 MJ, less than a factor of three from the nominal value at 7 TeV. With these parameters, operation entered into a regime where various effects due to high intensity bunches are observed (instabilities, beam-beam effects, e-cloud effects). The highly efficient collimation system limits beam losses that threaten to quench superconducting magnets. The correct functioning of the machine protection systems is vital during the different operational phases, where already a small fraction of the stored energy is sufficient to damage accelerator equipment or experiments in case of uncontrolled beam loss. Safe operation in presence of such high intensity proton beams is guaranteed by the interplay of many different systems: beam dumping system, beam interlocks, beam instrumentation, equipment monitoring, collimators and absorbers. The experience gained with the key systems of LHC machine protection and collimation will be discussed.
	Slides MOI1A01 [31.116 MB]

MOP245	Quench Tests at the Large Hadron Collider with Collimation Losses at 3.5 Z TeV	ion, proton, collimation, cryogenics	157
	S. Redaelli, R.W. Aßmann, G. Bellodi, K. Brodzinski, R. Bruce, F. Burkart, M. Cauchi, D. Deboy, B. Dehning, E.B. Holzer, J.M. Jowett, E. Nebot Del Busto, M. Pojer, A. Priebe, A. Rossi, M. Sapinski, M. Schaumann, R. Schmidt, M. Solfaroli Camillocci, G. Valentino, R. Versteegen, J. Wenninger, D. Wollmann, M. Zerlauth CERN, Geneva, Switzerland L. Lari IFIC, Valencia, Spain
	The Large Hadron Collider (LHC) has been operating since 2010 at 3.5 TeV and 4.0 TeV without experiencing quenches induced by losses from circulating beams. This situation might change at 7 TeV where the reduced margins in the superconducting magnets. The critical locations are the dispersion suppressors (DSs) at either side of the cleaning and experimental insertions, where dispersive losses are maximum. It is therefore crucial to understand in detail the quench limits with beam loss distributions alike those occurring in standard operation. In order to address this aspect, quench tests were performed by inducing large beam losses on the primary collimators of the betatron cleaning insertion, for proton and lead ion beams of 3.5 Z TeV, to probe the quench limits of the DS magnets. Losses up to 500 kW were achieved without quenches. The measurement technique and the results obtained are presented, including observations of heat loads in the cryogenics system.

MOP246	A Tool Based on the BPM-interpolated Orbit for Speeding up LHC Collimator Alignment	alignment, GUI, collider, betatron	162
	G. Valentino, N.J. Sammut University of Malta, Information and Communication Technology, Msida, Malta R.W. Aßmann, R. Bruce, G.J. Müller, S. Redaelli, B. Salvachua CERN, Geneva, Switzerland
	Beam-based alignment of the LHC collimators is required in order to measure the orbit center and beam size at the collimator locations. During an alignment campaign in March 2012, 80 collimators were aligned at injection energy (450 GeV) using automatic alignment algorithms in 7.5 hours, the fastest setup time achieved since the start of LHC operation in 2008. Reducing the alignment time even further would allow for more frequent alignments, providing more time for physics operation. The proposed tool makes use of the BPM-interpolated orbit to obtain an estimation of the beam centers at the collimators, which can be exploited to quickly move the collimator jaws from the initial parking positions to tighter settings before beam-based alignment commences.

Paper

Title

Other Keywords

Page

MOI1A01

LHC - Challenges in Handling Beams Exceeding 100 MJ

beam-losses, luminosity, collimation, injection

1

R. Schmidt
CERN, Geneva, Switzerland

The Large Hadron Collider (LHC) at CERN operates at 4 TeV with high intensity beams, with bunch intensities exceeding the nominal value by several 10 %. The energy stored in each beams is beyond 130 MJ, less than a factor of three from the nominal value at 7 TeV. With these parameters, operation entered into a regime where various effects due to high intensity bunches are observed (instabilities, beam-beam effects, e-cloud effects). The highly efficient collimation system limits beam losses that threaten to quench superconducting magnets. The correct functioning of the machine protection systems is vital during the different operational phases, where already a small fraction of the stored energy is sufficient to damage accelerator equipment or experiments in case of uncontrolled beam loss. Safe operation in presence of such high intensity proton beams is guaranteed by the interplay of many different systems: beam dumping system, beam interlocks, beam instrumentation, equipment monitoring, collimators and absorbers. The experience gained with the key systems of LHC machine protection and collimation will be discussed.

Slides MOI1A01 [31.116 MB]

MOP245

Quench Tests at the Large Hadron Collider with Collimation Losses at 3.5 Z TeV

ion, proton, collimation, cryogenics

157

S. Redaelli, R.W. Aßmann, G. Bellodi, K. Brodzinski, R. Bruce, F. Burkart, M. Cauchi, D. Deboy, B. Dehning, E.B. Holzer, J.M. Jowett, E. Nebot Del Busto, M. Pojer, A. Priebe, A. Rossi, M. Sapinski, M. Schaumann, R. Schmidt, M. Solfaroli Camillocci, G. Valentino, R. Versteegen, J. Wenninger, D. Wollmann, M. Zerlauth
CERN, Geneva, Switzerland
L. Lari
IFIC, Valencia, Spain

The Large Hadron Collider (LHC) has been operating since 2010 at 3.5 TeV and 4.0 TeV without experiencing quenches induced by losses from circulating beams. This situation might change at 7 TeV where the reduced margins in the superconducting magnets. The critical locations are the dispersion suppressors (DSs) at either side of the cleaning and experimental insertions, where dispersive losses are maximum. It is therefore crucial to understand in detail the quench limits with beam loss distributions alike those occurring in standard operation. In order to address this aspect, quench tests were performed by inducing large beam losses on the primary collimators of the betatron cleaning insertion, for proton and lead ion beams of 3.5 Z TeV, to probe the quench limits of the DS magnets. Losses up to 500 kW were achieved without quenches. The measurement technique and the results obtained are presented, including observations of heat loads in the cryogenics system.

MOP246

A Tool Based on the BPM-interpolated Orbit for Speeding up LHC Collimator Alignment

alignment, GUI, collider, betatron

162

G. Valentino, N.J. Sammut
University of Malta, Information and Communication Technology, Msida, Malta
R.W. Aßmann, R. Bruce, G.J. Müller, S. Redaelli, B. Salvachua
CERN, Geneva, Switzerland

Beam-based alignment of the LHC collimators is required in order to measure the orbit center and beam size at the collimator locations. During an alignment campaign in March 2012, 80 collimators were aligned at injection energy (450 GeV) using automatic alignment algorithms in 7.5 hours, the fastest setup time achieved since the start of LHC operation in 2008. Reducing the alignment time even further would allow for more frequent alignments, providing more time for physics operation. The proposed tool makes use of the BPM-interpolated orbit to obtain an estimation of the beam centers at the collimators, which can be exploited to quickly move the collimator jaws from the initial parking positions to tighter settings before beam-based alignment commences.