Main Objectives of the CARE-HHH APD collaboration

The aim of the CARE-HHH Network is to coordinate and integrate the activities of the accelerator and particle physics communities working together, in a worldwide context, towards achieving superior High-Energy High-Intensity Hadron Beam facilities for Europe. The specific objectives of the APD collaboration are:

Collaboration on fundamental Accelerator Physics and Optics Design problems which are common to existing machines or machines under construction, such that future high-energy/high-intensity hadron accelerators will profit from the proposed solutions. Best examples are optics design criteria for the LHC IR upgrade, booster synchrotrons, machine protection, and study of intensity limitations arising from conventional impedance, beam-beam or electron cloud effects. Beam dynamics studies provide important input for the required hardware developments and in particular for accelerator magnet design.
Reinforced exchange of information and experience between people from different universities and laboratories. A typical example is linear and nonlinear optics modelling, including space charge and machine imperfections, or the development of simulation codes to study halo formation and electron cloud effects. These codes need comparisons and benchmarking by beam measurements and are of common interest for high-luminosity hadron colliders and high-intensity synchrotrons.
In collaboration with CARE-HHH-ABI, establish a working infrastructure in Europe parallel to the proposed US-LARP programme, which has as objective to streamline R&D work in the 3 big national labs in the US with the additional benefit of contributing to LHC upgrade studies. A parallel US-LARP and CARE approach will facilitate further the important information flow and worldwide collaboration efforts.


Detailed description of Activities to be coordinated within the APD collaboration

APD activities cover 7 topics:

1.     APD1 Interaction Region design for an LHC luminosity upgrade:

i)           Design a new IR layout with D1/D2 separation-recombination dipole magnets in front of the triplet quadrupoles. This study requires mainly optics matching a study of the flexibility and options for this new layout  ( Dispersion matching; tuneability of the insertion, possibility of a symmetric optics, 'local' correction of the triplet field errors, minimum required crossing angle (this layout features a smaller than nominal number of long range beam-beam interactions), specification of the minimum required magnet apertures

ii)         Radiation hardness studies for a D1/D2 magnet package in front of the inner triplet magnets. This study requires simulations of the radiation levels coming from he IP's what is the maximum radiation level at the TAS absorber (now located between the D1/D2 dipoles), what is the minimum required length of the TAS, what is the expected neutral flux and how can one introduce a neutral absorber into this new IR layout, what are the radiation levels at the triplet quadrupoles (at the magnet coils and magnet centre)

iii)       Required field quality for the triplet and dipole magnets with β* = 0.25 meter. This study requires mainly simulations and potential machine experiments in existing hadron colliders specification of the magnet field quality in terms of multi-pole field error components and alignment tolerances.

2.     APD2 Optics design for booster synchrotrons in the SPS or LHC tunnel

i)           In collaboration with AMT2 and AMT3, i.e. "Magnets for an SPS upgrade" and "Magnets for a booster ring in the LHC tunnel" or for other future High-energy/High-intensity Proton Accelerators, such as or the GSI synchrotrons SIS 100/300.

3.     APD3 Impedance calculations for new experimental beam pipes and booster systems

4.     APD4 Generation of a structured list of intensity limits for the LHC operation: 

i)           e.g. first limit beam-beam interaction, second limit cooling capacity, third limit electron cloud etc. Such a list could help identifying the priorities with which one needs to work on the different origins for intensity limitations. The goal should be to specify the beam parameters for an 'ultimate' LHC upgrade.

5.     APD5 Studies on electron cloud effects for very high-intensity bunches.

i)           The following activities should be done by simulations AND experiments in existing storage rings:

                       i.     Acceptable bunch patterns for the LHC intensities and bunch parameters

                     ii.     Estimate of the electron cloud threshold currents for the SPS, LHC and potential new booster machines

                   iii.     Analysis of potential new remedies against electron cloud effects (ghost bunches, clearing electrodes, special bunch patterns for scrubbing)

                    iv.     Benchmarking of simulation codes with machine experiments

                      v.     Benchmarking and comparison of different simulation codes

6.     APD6 Studies on measurement procedures for nonlinear machine parameters.

This topic combines simulation studies and beam measurements (in collaboration with ABI) to

i)           Identify the applicability of existing procedures for the operation with high-intensity proton beams in the LHC  ( risk analysis, compatibility of the measurement with the LHC collimation system)

ii)         Develop an online simulation tool that can be used in the control room of future high-energy/high-intensity hadron accelerators.

7.     APD7 - Advanced theoretical studies on halo formation and loss mechanisms:

A future super conducting hadron collider requires advanced tuning strategies for the collimators, fulfilling at the same time requirements from machine protection, quench protection, and experimental background. This topic combines advanced accelerator physics, numerical tools, and physics topics.



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