IPAC2011 - List of Authors (Burkart, F.)

Paper	Title	Page
THPZ026	Collimation Dependent Beam Lifetime and Loss Rates in the LHC	3744
	D. Wollmann, R.W. Assmann, R. Bruce, F. Burkart, M. Cauchi, D. Deboy, S. Redaelli, A. Rossi, G. Valentino CERN, Geneva, Switzerland
	The four primary collimators in each LHC beam define the smallest aperture. Particles with high betatron amplitudes or momentum offset will therefore hit first a primary collimator. The instantaneous particle loss rate at primary collimators is an important measure for the global lifetime of the beams and a major ingredient to identify collimation induced performance limitations in the LHC. These loss rates have been measured during a number of LHC fills, featuring both "good" fills with high luminosity and "bad" fills with beam instabilities. The beam lifetime at the collimators was then calculated from this data for different cases. The results are presented and interpreted within this paper.

THPZ027	First Beam Results for a Collimator with In-jaw Beam Position Monitors	3747
	D. Wollmann, O. Aberle, R.W. Assmann, A. Bertarelli, C.B. Boccard, R. Bruce, F. Burkart, M. Cauchi, A. Dallocchio, D. Deboy, M. Gasior, O.R. Jones, S. Redaelli, A. Rossi, G. Valentino CERN, Geneva, Switzerland
	With more than 100 collimators the LHC has the most complex collimation system ever installed in an accelerator. The beam-based setup time of the system was a non-negligible factor during the commissioning of the LHC. In addition if the particle orbit at a collimator goes out of tolerance, this collimator needs to be setup again. To reduce the required setup time for the collimation system and to obtain the tight tolerances required for the LHC operation with small beta* and high beam energy, a new collimator design is being developed that integrates a beam position monitor (BPM) into the jaws of the collimator. A prototype of such a phase-II LHC collimator was installed in the SPS at CERN for the 2010 run. In this paper we present the first experimental results from the beam tests performed.

THPZ030	Halo Scrapings with Collimators in the LHC	3756
	F. Burkart, R.W. Assmann, R. Bruce, M. Cauchi, D. Deboy, S. Redaelli, A. Rossi, G. Valentino, D. Wollmann CERN, Geneva, Switzerland L. Lari IFIC, Valencia, Spain
	The population of the beam halo has been measured in the LHC with beam scraping experiments. Primary collimators of the LHC collimation system were used to scrape the beam halo at different statuses of the machine (injection, top energy, separated and colliding beams). In addition these measurements were used to calibrate the beam loss monitor signals to loss rates at the primary collimators. Within this paper the halo scraping method, the measured halo distribution and the calibration factors are presented and compared to theoretical predictions.

THPZ031	Acoustic Measurements in the Collimation Region of the LHC	3759
	D. Deboy, R.W. Assmann, C. Baccigalupi, F. Burkart, M. Cauchi, C.S. Derrez, J. Lendaro, A. Masi, S. Redaelli, G. Spiezia, D. Wollmann CERN, Geneva, Switzerland
	The LHC accelerator at CERN has the most advanced collimation system ever being installed. The collimators intercept unavoidable particle losses and therefore are essential to avoid beam induced quenches of the superconducting magnets. In addition, they provide passive machine protection against mis-kicked beams. During material robustness tests on a LHC collimator prototype in 2004 and 2006, vibration and acoustic measurements have shown that a beam impact detection system should be feasible using accelerometers and microphones as sensors in the LHC. Recently, such sensors have been installed close to the primary collimators in the LHC tunnel. First analyses of raw data show that the system is sensitive enough to detect beam scraping on collimators. Therefore, the implementation of a sophisticated acoustic monitoring system is under investigation. It may be useful not only to detect beam impacts on primary collimators in case of failure, but also to derive further information on beam losses that occur during regular operation. This paper gives an overview on the recent installation, results of the acoustic measurements made at the LHC, and future plans.

THPZ035	Comparison of LHC Collimation Setups with Manual and Semi-automatic Collimator Alignment	3771
	G. Valentino, R.W. Assmann, R. Bruce, F. Burkart, M. Cauchi, D. Deboy, S. Redaelli, A. Rossi, N.J. Sammut, D. Wollmann CERN, Geneva, Switzerland G. Valentino University of Malta, Information and Communication Technology, Msida, Malta
	The LHC collimation system beam-based alignment procedure has recently been upgraded to a semi-automatic process in order to increase its efficiency. In this paper, we describe the parameters used to measure the accuracy, stability and performance of the beam-based alignment of the LHC collimation system. This is followed by a comparison of the results at 450 GeV and 3.5 TeV with (1) a manual alignment and (2) with the results for semi-automatic alignment.

Paper

Title

Page

Collimation Dependent Beam Lifetime and Loss Rates in the LHC

3744

D. Wollmann, R.W. Assmann, R. Bruce, F. Burkart, M. Cauchi, D. Deboy, S. Redaelli, A. Rossi, G. Valentino
CERN, Geneva, Switzerland

The four primary collimators in each LHC beam define the smallest aperture. Particles with high betatron amplitudes or momentum offset will therefore hit first a primary collimator. The instantaneous particle loss rate at primary collimators is an important measure for the global lifetime of the beams and a major ingredient to identify collimation induced performance limitations in the LHC. These loss rates have been measured during a number of LHC fills, featuring both "good" fills with high luminosity and "bad" fills with beam instabilities. The beam lifetime at the collimators was then calculated from this data for different cases. The results are presented and interpreted within this paper.

THPZ027

First Beam Results for a Collimator with In-jaw Beam Position Monitors

3747

D. Wollmann, O. Aberle, R.W. Assmann, A. Bertarelli, C.B. Boccard, R. Bruce, F. Burkart, M. Cauchi, A. Dallocchio, D. Deboy, M. Gasior, O.R. Jones, S. Redaelli, A. Rossi, G. Valentino
CERN, Geneva, Switzerland

With more than 100 collimators the LHC has the most complex collimation system ever installed in an accelerator. The beam-based setup time of the system was a non-negligible factor during the commissioning of the LHC. In addition if the particle orbit at a collimator goes out of tolerance, this collimator needs to be setup again. To reduce the required setup time for the collimation system and to obtain the tight tolerances required for the LHC operation with small beta* and high beam energy, a new collimator design is being developed that integrates a beam position monitor (BPM) into the jaws of the collimator. A prototype of such a phase-II LHC collimator was installed in the SPS at CERN for the 2010 run. In this paper we present the first experimental results from the beam tests performed.

THPZ030

Halo Scrapings with Collimators in the LHC

3756

F. Burkart, R.W. Assmann, R. Bruce, M. Cauchi, D. Deboy, S. Redaelli, A. Rossi, G. Valentino, D. Wollmann
CERN, Geneva, Switzerland
L. Lari
IFIC, Valencia, Spain

The population of the beam halo has been measured in the LHC with beam scraping experiments. Primary collimators of the LHC collimation system were used to scrape the beam halo at different statuses of the machine (injection, top energy, separated and colliding beams). In addition these measurements were used to calibrate the beam loss monitor signals to loss rates at the primary collimators. Within this paper the halo scraping method, the measured halo distribution and the calibration factors are presented and compared to theoretical predictions.

THPZ031

Acoustic Measurements in the Collimation Region of the LHC

3759

D. Deboy, R.W. Assmann, C. Baccigalupi, F. Burkart, M. Cauchi, C.S. Derrez, J. Lendaro, A. Masi, S. Redaelli, G. Spiezia, D. Wollmann
CERN, Geneva, Switzerland

The LHC accelerator at CERN has the most advanced collimation system ever being installed. The collimators intercept unavoidable particle losses and therefore are essential to avoid beam induced quenches of the superconducting magnets. In addition, they provide passive machine protection against mis-kicked beams. During material robustness tests on a LHC collimator prototype in 2004 and 2006, vibration and acoustic measurements have shown that a beam impact detection system should be feasible using accelerometers and microphones as sensors in the LHC. Recently, such sensors have been installed close to the primary collimators in the LHC tunnel. First analyses of raw data show that the system is sensitive enough to detect beam scraping on collimators. Therefore, the implementation of a sophisticated acoustic monitoring system is under investigation. It may be useful not only to detect beam impacts on primary collimators in case of failure, but also to derive further information on beam losses that occur during regular operation. This paper gives an overview on the recent installation, results of the acoustic measurements made at the LHC, and future plans.

THPZ035

Comparison of LHC Collimation Setups with Manual and Semi-automatic Collimator Alignment

3771

G. Valentino, R.W. Assmann, R. Bruce, F. Burkart, M. Cauchi, D. Deboy, S. Redaelli, A. Rossi, N.J. Sammut, D. Wollmann
CERN, Geneva, Switzerland
G. Valentino
University of Malta, Information and Communication Technology, Msida, Malta

The LHC collimation system beam-based alignment procedure has recently been upgraded to a semi-automatic process in order to increase its efficiency. In this paper, we describe the parameters used to measure the accuracy, stability and performance of the beam-based alignment of the LHC collimation system. This is followed by a comparison of the results at 450 GeV and 3.5 TeV with (1) a manual alignment and (2) with the results for semi-automatic alignment.