HB2012 - List of Authors (Dallocchio, A.)

Paper	Title	Page
MOP240	High Energy Tests of Advanced Materials for Beam Intercepting Devices at CERN HiRadMat Facility	136
	A. Bertarelli, R.W. Aßmann, E. Berthomé, V. Boccone, F. Carra, F. Cerutti, A. Dallocchio, P. Francon, L. Gentini, M. Guinchard, N. Mariani, A. Masi, P. Moyret, S. Redaelli, S.D.M. dos Santos CERN, Geneva, Switzerland L. Peroni, M. Scapin Politecnico di Torino, Torino, Italy
	Predicting by simulations the consequences of LHC particle beams hitting Collimators and other Beam Intercepting Devices (BID) is a fundamental issue for machine protection: this can be done by resorting to highly non-linear numerical tools (Hydrocodes). In order to produce accurate results, these codes require reliable material models that, at the extreme conditions generated by a beam impact, are either imprecise or nonexistent. To validate relevant constitutive models or, when unavailable, derive new ones, a comprehensive experimental test foreseeing intense particle beam impacts on six different materials, either already used for present BID or under development for future applications, is being prepared at CERN HiRadMat facility. Tests will be run at medium and high intensity using the SPS proton beam (440 GeV). Material characterization will be carried out mostly in real time relying on embarked instrumentation (strain gauges, microphones, temperature and pressure sensors) and on remote acquisition devices (Laser Doppler Vibrometer and High-Speed Camera). Detailed post-irradiation analyses are also foreseen after the cool down of the irradiated materials.

MOP242	Experimental Verification for a Collimator with In-jaw Beam Position Monitors	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.

Paper

Title

Page

High Energy Tests of Advanced Materials for Beam Intercepting Devices at CERN HiRadMat Facility

136

A. Bertarelli, R.W. Aßmann, E. Berthomé, V. Boccone, F. Carra, F. Cerutti, A. Dallocchio, P. Francon, L. Gentini, M. Guinchard, N. Mariani, A. Masi, P. Moyret, S. Redaelli, S.D.M. dos Santos
CERN, Geneva, Switzerland
L. Peroni, M. Scapin
Politecnico di Torino, Torino, Italy

Predicting by simulations the consequences of LHC particle beams hitting Collimators and other Beam Intercepting Devices (BID) is a fundamental issue for machine protection: this can be done by resorting to highly non-linear numerical tools (Hydrocodes). In order to produce accurate results, these codes require reliable material models that, at the extreme conditions generated by a beam impact, are either imprecise or nonexistent. To validate relevant constitutive models or, when unavailable, derive new ones, a comprehensive experimental test foreseeing intense particle beam impacts on six different materials, either already used for present BID or under development for future applications, is being prepared at CERN HiRadMat facility. Tests will be run at medium and high intensity using the SPS proton beam (440 GeV). Material characterization will be carried out mostly in real time relying on embarked instrumentation (strain gauges, microphones, temperature and pressure sensors) and on remote acquisition devices (Laser Doppler Vibrometer and High-Speed Camera). Detailed post-irradiation analyses are also foreseen after the cool down of the irradiated materials.

MOP242

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

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.