Design and Manufacture of the Conduction Cooled Torus Coils for The Jefferson Laboratory 12-GeV Upgrade

The Hall B 3.6 T superconducting torus magnet is being designed and built as part of the Jefferson Lab 12 GeV upgrade. The magnet consists of 6 trapezoidal coils connected in series with an operating current of 3770 A. The magnet and the joints (or splices) connecting the coils are all conduction cooled by supercritical 4.6 K helium. This paper evaluates the stability requirements for the splices made between SSC Rutherford type cables. The basis for design and tests performed to evaluate the performance of the splices under varying incident magnetic fields are discussed along with test results.

Section: Introduction Ne Of the Main Challenges With The Jeffersonmentioning

confidence: 99%

Design and Evaluation of Joint Resistance in SSC Rutherford-Type Cable Splices for Torus Magnet for the Jefferson Lab 12-GeV Upgrade

Ghoshal

Fair

Hampshire

et al. 2016

“…The magnet design was carried out by Jefferson Laboratory [2,5] with each coil layer consisting of 117 turns of surplus Superconducting Super Collider dipole (SSC) NbTi Rutherford cable soldered into a stabilizing copper channel as shown in Fig 2(a) [4]. A typical coil structure is shown in Fig.…”

Section: Torus Magnet Design and Coil Manufacturingmentioning

confidence: 99%

“…These are double pancake coils vacuum impregnated with epoxy and assembled into an aluminum case. They are indirectly cooled by supercritical helium gas, producing what is referred to as the coil cold mass (CCM) [2,4]. Each coil within the aluminum case is conduction cooled via a series of thin copper sheets wrapped around each coil.…”

mentioning

confidence: 99%

Magnetic Field Mapping of the CLAS12 Torus—A Comparative Study Between the Engineering Model and Measurements at JLab

Ghoshal¹,

Beck²,

Fair³

et al. 2019

This paper provides an overview of the magnetic field measurement and subsequent electromagnetic re-modeling of the CLAS12 torus during the commissioning of the magnet in the fall of 2016. The CLAS12 detector in Hall B is part of the 12 GeV Accelerator Upgrade project at Jefferson Lab. The torus magnet allows precise determination of particle momenta within a cone ~ (5 0 -40 0 ) in the forward direction. The ability to do this requires we know the ∫B.dl of the torus to within an accuracy of 0.5 % or better. To achieve this, an accurate model of the field along the particle paths is required. The TOSCA code is used to generate a full 3D simulation of the magnetic envelope of the magnet as designed. Experimentally the actual magnetic field within the magnet was surveyed to confirm the model design and to measure the deviation from the ideal case. The magnetic field deviations are attributed to manufacturing variability and assembly tolerances. A final model was created with allowances for these deviations guided by the survey data to create a more precise field integral model which greatly improves momentum resolution capability allowing it to deliver the required specifications.

“…Cooling to the torus coils is provided by conduction cooling from a supercritical helium cooling tube around the inside perimeter of the coil [3], [5]. Two layers of OFE Copper sheet form the heat shield and distribute cooling to the coil through a solder connection located at the cooling tube.…”

Section: Heat Shield Solderingmentioning

confidence: 99%

“…Fermilab (FNAL) was contracted to provide eight coil cold masses to Jefferson Lab, six for the magnet with two spares. Because of the large geometry of the coils, FNAL had to develop new tooling and procedures for fabrication [3]. The tooling and procedures are described in this paper.…”

Section: Introductionmentioning

confidence: 99%

Overview of Torus Magnet Coil Production at Fermilab for the Jefferson Lab 12-GeV Hall B Upgrade

Krave

Velev

Makarov

et al. 2016

Self Cite

Fermi National Accelerator Laboratory (Fermilab) fabricated the torus magnet coils for the 12 GeV Hall B upgrade at Jefferson Laboratory (JLab). The production consisted of 6 large superconducting coils for the magnet and 2 spare coils. The toroidal field coils are approximately 2 m x 4 m x 5 cm thick. Each of these coils consists of two layers, each of which has 117 turns of copper-stabilized superconducting cable which will be conduction cooled by supercritical helium. Due to the size of the coils and their unique geometry, Fermilab designed and fabricated specialized tooling and, together with JLab, developed unique manufacturing techniques for each stage of the coil construction. This paper describes the tooling and manufacturing techniques required to produce the six production coils and two spare coils needed by the project.