Brookhaven leads various technical coordination efforts for the upgrade of the ATLAS detector, including constructing the new silicon tracker, liquid argon electronics, and the new muon chambers.
Brookhaven also contributes to the commissioning and future upgrade of the LHC itself in two areas: accelerator physics and superconducting magnets. This work is carried out as part of the U.S. LHC Accelerator Research Program (LARP) in collaboration with Fermilab, Lawrence Berkeley National Lab, and the Stanford Linear Accelerator Center. The ultimate goal of the upgrade program is to increase the rate and efficiency of particle collisions, a measure known as luminosity.
Much of the work for the U.S. LHC Accelerator Research Program uses Brookhaven's Relativistic Heavy Ion Collider (RHIC) as a "test bed" for the beam-based development of devices destined for the LHC. The LHC tune and chromaticity feedback hardware and algorithms, for example, were developed through collaboration between LARP and CERN in the RHIC collider. LARP will continue to perform R&D aimed at supporting LHC upgrades that strive to increase the LHC luminosity even further. For example, if "electron lenses" can be validated in action in RHIC, they may be used to combat the fundamental nonlinear disruptions caused by the beam-beam effect in both colliders. BNL is also taking a leading role in an international collaboration to develop "crab cavities," which, if successful, will allow proton bunches to collide (slightly) sideways as they pass through the collision points in the LHC, increasing luminosity while also allowing larger crossing angles to further minimize the damage done by the beam-beam effect.
CERN plans to upgrade the LHC in two phases. During Phase 1, scheduled for 2013, the dipoles located nearest ATLAS and CMS will be replaced with larger-aperture magnets. A proposal to use the design of the RHIC DX dipole, slightly modified, is now being written. For Phase 2, scheduled for 2017, BNL is working with Fermilab and Berkeley to develop superconducting quadrupoles made with a higher-performing superconductor, Nb3Sn, to replace the existing NbTi superconducting quadrupoles that focus the beam just prior to collisions. (See related story.)