HB2012 - List of Keywords (alignment)

Paper	Title	Other Keywords	Page
MOP218	Dynamics of Particles in a Tilted Solenoidal Focusing Channel	focusing, emittance, linac, solenoid	97
	H. Jiang, S. Fu IHEP, Beijing, People's Republic of China
	We use the paraxial ray approximation equations to analysis the dynamics of particles in a tilted solenoidal focusing channel. In this case, the particles' initial canonical angular momentum is nonzero, so we need to add the term of centrifugal potential to the dynamics equation of particles. And in the dynamics equation this centrifugal potential term is nonlinear, which results in the emittance growth. In practice, we also need to consider the spherical aberration's effect on emittance growth and the linear part of the space-charge force of a Kapchinskij-Vladimirskij distribution beam in the dynamics equation of particles.

MOP233	Error and Tolerance Studies for Injector II of C-ADS	linac, simulation, solenoid, emittance	125
	W.S. Wang, Y. He, Z.J. Wang IMP, Lanzhou, People's Republic of China
	The proposed Chinese Accelerator Driven System (C-ADS) driver linac is being designed by Chinese Academic Science (CAS). Injector II is designed and fabricated in Institute of Modern Physics (IMP). Injector II will accelerate 10 mA proton beams to 10 MeV. Because of the high final beam power (100 kW) specified for the linac operation, beam loss must be limited to 10^-5 level to avoid radiation damage. Misalignment and RF error simulation for cavities and focusing elements after RFQ were performed and the correction schemes developed using the computing code TRACK. Error and tolerance studies for Injector II are presented.

MOP242	Experimental Verification for a Collimator with In-jaw Beam Position Monitors	simulation, proton, collimation, closed-orbit	146
	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, V. Kain, L. Lari, A.A. Nosych, S. Redaelli, A. Rossi, G. Valentino CERN, Geneva, Switzerland
	At present the beam based alignment of the LHC collimators is performed by touching the beam halo with the two jaws of each device. This method requires dedicated fills at low intensities that are done infrequently because the procedure is time consuming. This limits the operational flexibility in particular in the case of changes of optics and orbit configuration in the experimental regions. The system performance relies on the machine reproducibility and regular loss maps to validate the settings. To overcome these limitations and to allow a continuous monitoring of the beam position at the collimators, a design with in-jaw beam position monitors was proposed and successfully tested with a mock-up collimator in the CERN SPS. Extensive beam experiments allowed to determine the achievable accuracy of the jaw alignment for single and multi-turn operation. In this paper the results of these experiments are discussed. The measured alignment accuracy is compared to the accuracies achieved with the present collimators in the LHC.

MOP246	A Tool Based on the BPM-interpolated Orbit for Speeding up LHC Collimator Alignment	insertion, 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

MOP218

Dynamics of Particles in a Tilted Solenoidal Focusing Channel

focusing, emittance, linac, solenoid

97

H. Jiang, S. Fu
IHEP, Beijing, People's Republic of China

We use the paraxial ray approximation equations to analysis the dynamics of particles in a tilted solenoidal focusing channel. In this case, the particles' initial canonical angular momentum is nonzero, so we need to add the term of centrifugal potential to the dynamics equation of particles. And in the dynamics equation this centrifugal potential term is nonlinear, which results in the emittance growth. In practice, we also need to consider the spherical aberration's effect on emittance growth and the linear part of the space-charge force of a Kapchinskij-Vladimirskij distribution beam in the dynamics equation of particles.

MOP233

Error and Tolerance Studies for Injector II of C-ADS

linac, simulation, solenoid, emittance

125

W.S. Wang, Y. He, Z.J. Wang
IMP, Lanzhou, People's Republic of China

The proposed Chinese Accelerator Driven System (C-ADS) driver linac is being designed by Chinese Academic Science (CAS). Injector II is designed and fabricated in Institute of Modern Physics (IMP). Injector II will accelerate 10 mA proton beams to 10 MeV. Because of the high final beam power (100 kW) specified for the linac operation, beam loss must be limited to 10^-5 level to avoid radiation damage. Misalignment and RF error simulation for cavities and focusing elements after RFQ were performed and the correction schemes developed using the computing code TRACK. Error and tolerance studies for Injector II are presented.

MOP242

Experimental Verification for a Collimator with In-jaw Beam Position Monitors

simulation, proton, collimation, closed-orbit

146

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, V. Kain, L. Lari, A.A. Nosych, S. Redaelli, A. Rossi, G. Valentino
CERN, Geneva, Switzerland

At present the beam based alignment of the LHC collimators is performed by touching the beam halo with the two jaws of each device. This method requires dedicated fills at low intensities that are done infrequently because the procedure is time consuming. This limits the operational flexibility in particular in the case of changes of optics and orbit configuration in the experimental regions. The system performance relies on the machine reproducibility and regular loss maps to validate the settings. To overcome these limitations and to allow a continuous monitoring of the beam position at the collimators, a design with in-jaw beam position monitors was proposed and successfully tested with a mock-up collimator in the CERN SPS. Extensive beam experiments allowed to determine the achievable accuracy of the jaw alignment for single and multi-turn operation. In this paper the results of these experiments are discussed. The measured alignment accuracy is compared to the accuracies achieved with the present collimators in the LHC.

MOP246

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

insertion, 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.