Design of the Super Conducting Super High Momentum Spectrometer (SHMS) for the JLAB 12 GeV Upgrade

A collaboration between NSCL and Jlab has developed the reference design and coil winding for Jlab's Super High Momentum Spectrometer (SHMS) horizontal bend magnet. A warm iron "C" type superferric dipole magnet will bend the 12 GeV/c particles horizontally by 3 to allow the SHMS to reach angles as low as 5.5 . This requires an integral field strength of up to 2.1 T.m. The major challenges are the tight geometry, high and unbalanced forces and a required low fringe field in primary beam path. A coil design based on flattened SSC Rutherford cable that provides a large current margin and commercially available fiberglass prepreg epoxy tape has been developed. A complete test coil has been wound and will be cold tested. This paper present the modified magnet design includes coil forces, coil restraint system and fringe field. In addition, coil properties, quench calculations and the full mechanical details are also presented.Index Terms-Cryostat, dipole magnet, superferric, warm iron.

Section: Conceptual Designmentioning

confidence: 85%

The Superconducting Horizontal Bend Magnet for the Jefferson Lab's 11 GeV/c Super High Momentum Spectrometer

Chouhan

DeKamp

Zeller

et al. 2010

“…These magnets are cryogenically identical but have different warm iron yokes optimized for each magnets actual excitation. The requirements of the SHMS spectrometer require that the Q2 quad operates at or near (83%) its design maximum gradient, while the Q3 quad only operates at 60% of its required excitation thus affording some measure of redundancy if the final performances of the Q2 and Q3 magnets turn out not to be equal [8].…”

Section: Technical Challenges and Risk Mitigationsmentioning

confidence: 99%

Superconducting Magnets for the 12 GeV Upgrade at Jefferson Laboratory

Fair

Young

2015

Jefferson Laboratory is embarked on an energy upgrade to its flagship continuous electron beam accelerator in order to expand the scope of its research capabilities and probe further into the structure of nuclear particles. The 12 GeV upgrade includes the design, manufacture, integration, installation and commissioning of eight different superconducting magnets in three separate experimental halls. The effort involves other national laboratories, universities and industry spanning three countries. This paper will summarize the key characteristics of these magnets, ranging in size from 0.2 to 23 MJ in stored energy, and featuring many different types and configurations. The paper will also give an overview of the specific technical challenges for each magnet, and a status report on magnet manufacture and expected delivery dates. The 12GeV upgrade at J-Lab represents the largest superconducting magnet fabrication and installation program currently ongoing in the United States and this paper will present the breadth of collaborations supporting it.  Index Terms-12 GeV upgrade, continuous electron beam accelerator, superconducting magnets, Jefferson Lab Manuscript received August 08, 2014.

“…Efferson Lab's 11 GeV Super High Momentum Spectrometer (SHMS)-comprising of the following dipole and quadrupole magnets: Horizontal Bend (HB) dipole, Q1, Q2, Q3, and main Dipole-has been successfully commissioned and in operation since 2017. The Q1 was commissioned in April 2015; HB in January 2016; Q2 in December 2016; and Q3 and Dipole in February 2017 [1][2][3][4][5]. All five superconducting magnets met their maximum current operational levels at the 11 GeV specifications for Hall C [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Test Results of Fast Decaying Current-Induced AC Losses in SHMS Superconducting Magnets at Jefferson Lab

Sun

Lassiter

Ghoshal

et al. 2020

The 11 GeV Super High Momentum Spectrometer (SHMS) of Hall C, part of the recent 12 GeV accelerator Upgrade at Jefferson Lab, was successfully commissioned in 2017. Fast current discharges of the SHMS Q2, Q3 quadrupoles and dipole superconducting magnets experienced some level of operational difficulty, during commissioning and normal operation. Measurements and analyses demonstrate that the fast current discharge leads to substantial AC losses in the conductor and subsequently triggers a quench-back effect. The details of the measurements and analyses have been reported previously. This paper focuses on the test results of the magnets using a reduced value of the protection dump resistor for each magnet to lower the current decay rate. The test results confirmed that the reduced dump resistances eliminated the quench-back effect for the SHMS Q2, Q3 and Dipole magnets, thus improving their cryogenic operability.