Tuning shims for high field quality in superconducting magnets

A high field quality in interaction region quadrupoles is crucial to the luminosity performance of high energy colliders such as the Relativistic Heavy Ion Collider (RHIC). The field quality in magnets is limited in part by manufacturing tolerances in the parts and assembly. A tuning shim method has been developed to reduce the relative field errors ({Delta}B/B) from {approximately}10{sup {minus}4} to {approximately}10{sup {minus}5} at 2/3 of the coil radius. Eight tuning shims having a variable thickness of iron are inserted after the construction and measurement of field harmonics in the magnet. In this paper the tuning shim technique is described for RHIC interaction region quadrupoles. The results of calculations and measurement are also presented

The magnet system of the Relativistic Heavy Ion Collider (RHIC)

The Relativistic Heavy Ion Collider now under construction at Brookhaven National Laboratory (BNL) is a colliding ring accelerator to be completed in 1999. Through collisions of heavy ions it is hoped to observe the creation of matter at extremely high temperatures and densities, similar to what may have occurred in the original "Big Bang." The collider rings will consist of 1740 superconducting magnet elements. Some of elements are being manufactured by industrial partners (Northrop Grumman and Everson Electric). Others are being constructed or assembled at BNL. A description is given of the magnet designs, the plan for manufacturing and test results. In the manufacturing of the magnets, emphasis has been placed on uniformity of their performance and on quality. Results so far indicate that this emphasis has been very successful

Rapid cycling dipole magnet

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Vibration Measurements to Study the Effect of Cryogen Flow in Superconducting Quadrupole.

The conceptual design of compact superconducting magnets for the International Linear Collider final focus is presently under development. A primary concern in using superconducting quadrupoles is the potential for inducing additional vibrations from cryogenic operation. We have employed a Laser Doppler Vibrometer system to measure the vibrations in a spare RHIC quadrupole magnet under cryogenic conditions. Some preliminary results of these studies were limited in resolution due to a rather large motion of the laser head as well as the magnet. As a first step towards improving the measurement quality, a new set up was used that reduces the motion of the laser holder. The improved setup is described, and vibration spectra measured at cryogenic temperatures, both with and without helium flow, are presented

Insertion Magnets

Chapter 3 in High-Luminosity Large Hadron Collider (HL-LHC) : Preliminary Design Report. The Large Hadron Collider (LHC) is one of the largest scientific instruments ever built. Since opening up a new energy frontier for exploration in 2010, it has gathered a global user community of about 7,000 scientists working in fundamental particle physics and the physics of hadronic matter at extreme temperature and density. To sustain and extend its discovery potential, the LHC will need a major upgrade in the 2020s. This will increase its luminosity (rate of collisions) by a factor of five beyond the original design value and the integrated luminosity (total collisions created) by a factor ten. The LHC is already a highly complex and exquisitely optimised machine so this upgrade must be carefully conceived and will require about ten years to implement. The new configuration, known as High Luminosity LHC (HL-LHC), will rely on a number of key innovations that push accelerator technology beyond its present limits. Among these are cutting-edge 11-12 tesla superconducting magnets, compact superconducting cavities for beam rotation with ultra-precise phase control, new technology and physical processes for beam collimation and 300 metre-long high-power superconducting links with negligible energy dissipation. The present document describes the technologies and components that will be used to realise the project and is intended to serve as the basis for the detailed engineering design of HL-LHC.Comment: 19 pages, Chapter 3 in High-Luminosity Large Hadron Collider (HL-LHC) : Preliminary Design Repor

Superconducting Magnets for a Final Focus Upgrade of ATF2

Original publication available at http://www.jacow.org/International audienceThe Accelerator Test Facility 2 (ATF2) at KEK is a scaled version of the final focus (FF) design proposed for a future linear collider (LC). A primary ATF2 goal is to experimentally verify the FF technology needed to obtain very small, stable beam spots at an LC interaction point [1]. Initially the ATF2 FF is made using conventional (warm) quadrupole and sextupole magnets. We intend to upgrade the ATF2 FF by replacing conventional magnets with new superconducting ones that use the same technology proposed for the International Linear Collider (ILC) baseline FF magnets [2]. With this upgrade we can investigate smaller interaction point beta-functions and study superconducting magnet vibration stability in an accelerator environment. Our ATF2 magnet cryostat design incorporates features to facilitate monitoring of the cold mass movement via interferometric techniques. The status and future plans for the ATF2 superconducting magnet upgrade are reported here

Design of Nb3Sn Coils for LARP Long Magnets

The LHC Accelerator Research Program (LARP) has a primary goal to develop, assemble, and test full size Nb{sub 3}Sn quadrupole magnet models for a luminosity upgrade of the Large Hadron Collider (LHC). A major milestone in this development is to assemble and test, by the end of 2009, two 4 m-long quadrupole cold masses, which will be the first Nb{sub 3}Sn accelerator magnet models approaching the length of real accelerator magnets. The design is based on the LARP Technological Quadrupoles (TQ), under development at FNAL and LBNL, with gradient higher than 200 T/m and aperture of 90 mm. The mechanical design will be chosen between two designs presently explored for the TQs: traditional collars and Al-shell based design (preloaded by bladders and keys). The fabrication of the first long quadrupole model is expected to start in the last quarter of 2007. Meanwhile the fabrication of 4 m-long racetrack coils started this year at BNL. These coils will be tested in an Al-shell based supporting structure developed at LBNL. Several challenges have to be addressed for the successful fabrication of long Nb{sub 3}Sn coils. This paper presents these challenges with comments and solutions adopted or under study for these magnets. The coil design of these magnets, including conductor and insulation features, and quench protection studies are also presented

Common Coil Magnet Program at Bnl.

The goal of the common coil magnet R&D program at Brookhaven National Laboratory (BNL) is to develop a 12.5 T, 40 mm aperture dipole magnet using ''React and Wind Technology'' with High Temperature Superconductors (HTS) playing a major role. Due to its ''conductor friendly'' nature, the common coil design is attractive for building high field 2-in-1 dipoles with brittle materials such as HTS and Nb{sub 3}Sn. At the current rate of development, it is expected that a sufficient amount of HTS with the required performance would be available in a few years for building a short magnet. In the interim, the first generation dipoles will be built with Nb{sub 3}Sn superconductor. They will use a ''React and Wind'' technology similar to that used in HTS and will produce a 12.5 T central field in a 40 mm aperture. The Nb{sub 3}Sn coils and support structure of this magnet will become a part of the next generation hybrid magnet with inner coils made of HTS. To develop various aspects of the technology in a scientific and experimental manner, a 10-turn coil program has been started in parallel. The program allows a number of concepts to be evaluated with a rapid throughput in a cost-effective way. Three 10-turn Nb{sub 3}Sn coils have been built and one HTS coil is under construction. The initial test results of this ''React & Wind'' 10-turn coil program are presented. It is also shown that a common coil magnet design can produce a field quality that is as good as a conventional cosine theta design

LARP Long Nb3Sn Quadrupole Design

A major milestone for the LHC Accelerator Research Program (LARP) is the test, by the end of 2009, of two 4m-long quadrupole magnets (LQ) wound with Nb3Sn conductor. The goal of these magnets is to be a proof of principle that Nb3Sn is a viable technology for a possible LHC luminosity upgrade. The design of the LQ is based on the design of the LARP Technological Quadrupoles, presently under development at FNAL and LBNL, with 90-mm aperture and gradient higher than 200 T/m. The design of the first LQ model will be completed by the end of 2007 with the selection of a mechanical design. In this paper we present the coil design addressing some fabrication technology issues, the quench protection study, and three designs of the support structure

Design of Nb3Sn coils for LARP long magnets

The LHC Accelerator Research Program (LARP) has a primary goal to develop, assemble, and test full size Nb{sub 3}Sn quadrupole magnet models for a luminosity upgrade of the Large Hadron Collider (LHC). A major milestone in this development is to assemble and test, by the end of 2009, two 4m-long quadrupole cold masses, which will be the first Nb3Sn accelerator magnet models approaching the length of real accelerator magnets. The design is based on the LARP Technological Quadrupoles (TQ), under development at FNAL and LBNL, with gradient higher than 200 T/m and aperture of 90 mm. The mechanical design will be chosen between two designs presently explored for the TQs: traditional collars and Al-shell based design (preloaded by bladders and keys). The fabrication of the first long quadrupole model is expected to start in the last quarter of 2007. Meanwhile the fabrication of 4m-long racetrack coils started this year at BNL. These coils will be tested in an Al-shell based supporting structure developed at LBNL. Several challenges have to be addressed for the successful fabrication of long Nb{sub 3}Sn coils. This paper presents these challenges with comments and solutions adopted or under study for these magnets. The coil design of these magnets, including conductor and insulation features, and quench protection studies are also presented