Commissioning scenarios and tests for the LHC collimation system

The physics reach of the LHC requires unprecedented luminosity and beam intensity in proton-proton collisions. The maximum intensity in the LHC is directly coupled to the maximum peak beam loss rate and the cleaning efficiency from the collimation system. A sophisticated LHC collimation system is implemented in two cleaning insertions and in the experimental areas. In a first phase 88 collimators are installed, being controlled by 344 stepping motors in total. The work of this PhD analyzes the achievable cleaning efficiency with realistic imperfections, defines the required collimator settings and establishes available tolerances for collimator setup and transient optics changes. An optimal setup strategy can optimize cleaning efficiency, ensure passive protection, maximize tolerances, minimize the required beam time for setup of the system and support the expected evolution in LHC beam intensity. Such an optimized strategy is described.

[1]  B. Dehning,et al.  Modeling of Quench Limit for Steady State Heat Deposits in LHC Magnets , 2008, IEEE Transactions on Applied Superconductivity.

[2]  D. Edwards,et al.  An Introduction to the Physics of High Energy Accelerators: Edwards/An Introduction , 2008 .

[3]  W. Höfle,et al.  LHC TRANSVERSE FEEDBACK DAMPING EFFICIENCY , 2008 .

[4]  B. Dehning,et al.  GENERATION OF 1.5 MILLION BEAM LOSS THRESHOLD VALUES , 2008 .

[5]  R. Assmann,et al.  BEAM CLEANING AND BEAM LOSS CONTROL , 2008 .

[6]  Ralph Wolfgang Assmann,et al.  COLLIMATEUR INTEGRATION AND INSTALLATION EXAMPLE OF ONE OBJECT TO BE INSTALLED IN THE LHC , 2008 .

[7]  T. Weiler,et al.  LHC collimation system hardware commissioning , 2007, 2007 IEEE Particle Accelerator Conference (PAC).

[8]  B. Goddard,et al.  LHC machine protection , 2007, 2007 IEEE Particle Accelerator Conference (PAC).

[9]  A. Masi,et al.  The LHC collimator controls architecture - design and beam tests , 2007, 2007 IEEE Particle Accelerator Conference (PAC).

[10]  S. Redaelli,et al.  Scenarios for beam commissioning of the LHC collimation system , 2007, 2007 IEEE Particle Accelerator Conference (PAC).

[11]  Walter Scandale.  Crystal collimation as an option for the LHC , 2007, International Conference on Charged and Neutral Particles Channeling Phenomena.

[12]  O. R. Jones,et al.  Transverse impedance of LHC collimators , 2007 .

[13]  T. Weiler.  Results of the studies on energy deposition in IR6 superconducting magnets from continuous beam loss on the TCDQ system , 2007 .

[14]  R. Steinhagen.  LHC Beam Stability and Feedback Control - Orbit and Energy - , 2007 .

[15]  J. B. Jeanneret.  GEOMETRICAL TOLERANCES FOR THE QUALIFICATION OF LHC MAGNETS , 2007 .

[16]  Ralph Wolfgang Assmann,et al.  Permanent Deformation of the LHC Collimator Jaws Induced by Shock Beam Impact: an Analytical and Numerical Interpretation , 2006 .

[17]  G. Robert-Demolaize,et al.  Design and Performance Optimization of the LHC Collimation System , 2006 .

[18]  A. Ferrari,et al.  COLLIMATION EFFICIENCY DURING COMMISSIONING , 2006 .

[19]  S. Redaelli,et al.  Tune Shift Induced By Nonlinear Resistive Wall Wake Field Of Flat Collimator , 2006 .

[20]  S. Calatroni,et al.  LHC Collimation: Design and Results from Prototyping and Beam Tests , 2005, Proceedings of the 2005 Particle Accelerator Conference.

[21]  G. Spiezia,et al.  Detecting Impacts of Proton Beams on the LHC Collimators with Vibration and Sound Measurements , 2005, Proceedings of the 2005 Particle Accelerator Conference.

[22]  E. Métral.  Overview of Impedance and Single-Beam Instability Mechanisms , 2005, Proceedings of the 2005 Particle Accelerator Conference.

[23]  S. Redaelli,et al.  A New Version of Sixtrack with Collimation and Aperture Interface , 2005, Proceedings of the 2005 Particle Accelerator Conference.

[24]  S. Redaelli,et al.  LHC APERTURE AND COMMISSIONING OF THE COLLIMATION SYSTEM , 2005 .

[25]  Verena Kain,et al.  Machine protection and beam quality during the LHC injection process , 2005 .

[26]  Ralph Wolfgang Assmann,et al.  THE MECHANICAL DESIGN FOR THE LHC COLLIMATORS , 2004 .

[27]  B. Goddard,et al.  AN IMPROVED COLLIMATION SYSTEM FOR THE LHC , 2004 .

[28]  Michael E. Hodgson,et al.  Design of the Beam Loss Monitoring System for the LHC Ring , 2004 .

[29]  L. Vos,et al.  Transverse Resistive Wall Impedance and Wake Function with "Inductive Bypass" , 2004 .

[30]  H. Burkhardt,et al.  INTENSITY AND LUMINOSITY AFTER BEAM SCRAPING , 2004 .

[31]  F. Schmidt,et al.  Tools for predicting cleaning efficiency in the LHC , 2003, Proceedings of the 2003 Particle Accelerator Conference.

[32]  K. Bane.  A Simplified Model of Intrabeam Scattering , 2002, physics/0206002.

[33]  B. Goddard,et al.  Requirements for the LHC collimation system , 2002 .

[34]  B. Goddard,et al.  The Consequences of Abnormal Beam Dump Actions on the LHC Collimation System , 2002 .

[35]  R. Assmann,et al.  Efficiency for the imperfect LHC collimation system , 2002 .

[36]  F. Schmidt,et al.  EQUILIBRIUM BEAM DISTRIBUTION AND HALO IN THE LHC , 2002 .

[37]  R. Cahn.  Cross-section formulae for specific processes , 2000 .

[38]  Atomic and nuclear properties of materials , 2000 .

[39]  J. Jeanneret.  Optics of a two-stage collimation system , 1998 .

[40]  E. Keil.  Synchrotron radiation dominated hadron colliders , 1997, Proceedings of the 1997 Particle Accelerator Conference (Cat. No.97CH36167).

[41]  D. Leroy,et al.  Quench levels and transient beam losses in LHC magnets , 1996 .

[42]  R. Walker.  RADIATION DAMPING , 1996 .

[43]  J. Jeanneret,et al.  The Principles of Two Stage Betatron and Momentum Collimation in Circular Accelerators , 1995 .

[44]  A F Wrulich,et al.  Single-beam lifetime , 1994 .

[45]  J Rossbach,et al.  Basic course on accelerator optics , 1993 .

[46]  K. Potter.  Luminosity measurements and calculations , 1985 .

[47]  Robert Walgate,et al.  Synchrotron radiation , 1984, Nature.

[48]  K. Goulianos.  Diffractive interactions of hadrons at high energies , 1983 .

[49]  C. Case,et al.  MOLIERE'S THEORY OF MULTIPLE SCATTERING. , 1968 .

[50]  E. Lillethun,et al.  Proton-nuclei cross sections at 20 GeV , 1966 .