WP5: Collimation

Objectives

Task 5.1: Coordination & Communication

  • To coordinate and schedule work package tasks 

  • To monitor work progress and inform the project management and work package participants 

  • To follow up the WP budget and use of resources 

  • To prepare internal and deliverable reports

Task 5.2: Simulations of Beam Loss in the Experimental IRs

  • Assess locations and magnitudes of beam loss in the experimental IRs for various upgrade scenarios. 

  • Study impact of imperfections on beam loss. 

  • Explore interplay of IR beam losses with machine parameters (beta*, crossing angle). 

  • Specify operational tolerances related to collimation and the IR upgrade. 

  • Define beam impact scenarios for energy depositions studies and collimator design. 

  • Prepare input for energy deposition studies.

Task 5.3: Simulations of Energy Deposition in the Experimental IRs

  • Assess locations and magnitude of energy deposition in the IRs for various upgrade scenarios including imperfections. 

  • Investigate any possibly required shielding requirements. 

  • Provide input to collimator design. 

  • Prepare input for background simulations.

Task 5.4: Design of Collimation in the Experimental IRs

  • Study required collimation to keep losses at the same level or below before the IR upgrade. 

  • Specification of collimator requirements. 

  • Integration of collimators, new layout and optics. 

  • Feed forward to simulation WPs.

Description of work

Task 5.1: Coordination & Communication

The activities of this task are for the work package coordinators [CERN, RHUL] to oversee and co-ordinate the work of all other work package tasks, to ensure the consistency of the work according to the project plan and to coordinate the WP technical and scientific tasks with tasks carried out by the other work packages when relevant. The coordination duties also include the organization of WP internal steering meetings, the setting up of proper reviewing, the reporting to the project management and the distribution of the information within the WP as well as to the other work packages running in parallel. The task also covers the organization of and support to the annual meetings dedicated to the WP activity review and possible activity workshops or specialized working sessions, implying the attendance of invited participants from inside and outside the consortium.

Task 5.2: Simulations of Beam Loss in the Experimental IRs

The upgrade of the LHC insertions for a low beta optics will change both the beam size and the available aperture in the experimental IRs. Beam loss simulations will be set up for a limited set of upgrade scenarios for evaluating proton losses after the upgrade of the LHC. Realistic imperfections will be specified and included into the studies. Various computer programmes will be used and the results compared. Some programmes include simulation of impedance effects. CERN and CSIC will use the Sixtrack/Collimation code, RHUL a GEANT-based code and UNIMAN the Merlin code. The interplay of IR beam losses with machine parameters (beta*, crossing angle) will be evaluated and operational tolerances related to collimation and the IR upgrade will be studied. This WP will also define beam impact scenarios for energy depositions studies and collimator design. The numerical computer programmes will be used to prepare input for energy deposition studies.

Task 5.3: Simulations of Energy Deposition in the Experimental IRs

Each IR upgrade scenario must be qualified in terms of energy deposition and power load on various accelerator components and infrastructure items. Detailed models will be set up for the modified IRs. Including the input from WP 5.2 energy deposition will be calculated including the impact of imperfections. Any need and effects from shielding will be studied. The energy deposition results will be used to define required input to collimator design. Particle fluxes will be recorded at well-defined interface planes to the experiments and will be provided for simulations of background in the particle physics experiments. At CERN and UNIMAN the FLUKA code and at RHUL the GEANT based code will be used. The partners will agree on the focus of work and split of the IRs to be studied. For example, a partner might be asked to study in detail IR1, while another partner focuses on IR5 and CERN is cross-checking results and consistency.

Task 5.4: Design of Collimation in the Experimental IRs

The results on beam loss and energy deposition will be used to evaluate the need for improved collimation in the experimental IRs. This WP will define the locations, materials and dimensions of collimators and absorbers in the IRs. The partners involved – CERN and CSIC – will concentrate on different IR’s, which have different space constraints. Functional collimator specifications will be provided. For existing collimators it will be decided whether they can remain in their original position of need to moved or removed. The integration of the modified collimation scheme will be addressed and any possible integration constraints will be fed back to simulation studies and the proposed solutions.

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