CERN Accelerating science

Article
Title	Optimization of Open Midplane Dipole Design for LHC IR Upgrade
Author(s)	Gupta, Ramesh C ; Anerella, Michael ; Ghosh, Arup ; Harrison, Michael ; Mokhov, Nikolai V ; Schmalzle, Jesse D ; Wanderer, Peter
Affiliation	(BNL, Upton, Long Island, New York) ; (Fermilab, Batavia, Illinois)
Publication	2005
In:	21st IEEE Particle Accelerator Conference, Knoxville, TN, USA, 16 - 20 May 2005, pp.3055
Subject category	Accelerators and Storage Rings
Abstract	The proposed ten-fold increase in Large Hadron Collider (LHC) luminosity requires high field ( 15 T) magnets that are subjected to the high radiation power of  9 kW/per beam directed towards each interaction region. This has a major impact in the design of first dipole in the "Dipole First" optics. The proposed design allows sufficient clear space between coils so that most of the particle showers from the interaction points (concentrated at the midplane due to strong magnetic field) can be transported outside the coil region to a warm absorber thus drastically reducing the peak power density in the coils and removing heat at a higher (nitrogen) temperature. The concept, however, presents several new technical challenges: (a) obtaining good field quality despite a large midplane gap, (b) minimizing peak fields on coil, (c) dealing with large vertical forces with no structure between the coils, (d) minimizing heat deposition in the cold region, (e) designing a support structure. Designs with different horizontal and vertical coil spacing are presented that offer significant savings in the operating and infrastructure cost of the cryo-system, providing reliable quench-stable operation with a lifetime of the critical components of at least ten years.