US LHC Accelerator Research Program (LARP)

1. US LHC Accelerator Research Program (LARP) Eric Prebys* • Accelerator Systems • Accelerator Systems includes • Instrumentation • Schottky Monitor • Tune Tracker • AC Dipole • Luminosity Monitor • Collimation • Rotatable Collimators • Crystal Collimation Studies • Accelerator Physics • Beam-beam • Space Charge • Electron Cloud • PS2 (new synchrotron for CERN) • Crab Cavities Luminosity Monitor An ionization detector installed in the neutral absorbers on each side of the ATLAS and CMS interaction regions. Rate and radiation levels have made the design challenging. • Background • Proposed in 2003 to coordinate efforts at US labs related to the LHC accelerator (as opposed to CMS or ATLAS) • Originally FNAL, BNL, and LBNL • SLAC joined shortly thereafter • Some work (AC Dipole) supported at UT Austin • LARP Goals • Advance International Cooperation in High Energy Accelerators • Advance High Energy Physics • By helping the LHC integrate luminosity as quickly as possible • Advance U.S. Accelerator Science and Technology • LARP includes projects related to initial operation, but a significant part of the program concerns the LHC upgrades • Current Budget: $12-13M/year. AC Dipole This device drives small oscillations in the beam in order to measure both linear and non-linear lattice terms. Rotatable Collimators These collimators have multiple facets, such that damaged surfaces can be rotated away in the event of catastrophic beam loss. Magnet Systems The goal of the LARP magnet program is to demonstrate the viability of magnets based on Nb3Sn superconductor on a timescale which would allow them to be utilized on the LHC Phase II upgrade in approximately 2020. Nb3Sn allows larger gradients/apertures and/or larger temperature margins than traditional NbTi, but it has never been used to make accelerator quality magnets before. Design Comparison LARP has investigated two designs for the magnets: Challenging Material Whereas NbTi remains pliable in its superconducting state, Nb3Sn becomes brittle during the required heated reaction steps. Cables must therefore be wound on a mandrill, baked, and then carefully transferred to the magnet. PS2 The PS2 has been proposed to replace the 50 year old PS. LARP is taking part in a number of studies, including the effects of electron cloud and space charge. • Collar • Traditional magnet design. • Pre-load provided by a series of collars which hold coils in place. • Shell • New concept • Pre-load produced by inflatable bladder, and maintained keys, which are inserted.. 120 mm aperture Crab Cavities Crab cavities are superconducting RF cavities which deflect bunches such that they collide head on, even when the beams cross at an angle. This technology has recently been endorsed by CERN for the Phase II upgrade. Pushing all Parameters LARP magnet subprograms investigate all aspects of magnet design: Nominal Choice Technical Quad (TQ) 1m magnets with 90mm apertures were produced with both collar and shell designs. All reached gradients of >200 T/m. Personnel Programs LARP funds two programs to support US personnel working at CERN. Long Quad (LQ) The long quad program has produced a 4m magnet with a 90mm aperture and a design gradient of 200 T/m based on a shell design. It is scheduled to be tested next month. Long Term Visitors (LTV) Program This program provides support for more senior personnel to spend extended periods at CERN, doing accelerator related R&D or helping to commission the LHC. Salary is provided by the home institution, while LARP pays relocation and cost of living expenses. Toohig Fellowship A competitive postdoctoral fellowship open to recent PhD recipients. Successful candidates are expected to spend approximately half of their time at CERN and half at the LARP host lab of their choice. High Gradient Quad (HQ) A 1m magnet with a 120mm aperture and a design gradient of 200 T/m based on the shell approach is being built and is scheduled to be tested in FY10. www.uslarp.org *Fermi National Accelerator Lab, PO 500, Batavia IL, 60510