The Cosine Two Theta Quadrupole Magnets for the Jefferson Lab Super High Momentum Spectrometer...

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  • The Cosine Two Theta Quadrupole Magnets for the Jefferson Lab Super High Momentum Spectrometer (SHMS).P.B. Brindza, S.R. Lassiter M. J. Fowler Abstract The Jefferson Lab 12 GeV upgrade involves building a new 12 Gev/c spectrometer for JLAB Hall C called the SHMS. This device achieves 4.5 mStr acceptance at bend angles for 5.5 degrees to 40 degrees by using five magnetic elements in a dQQQD configuration. The Q1 SC quad is described elsewhere in this Conference and is an evolution of a cold iron magnet used previously for the existing JLAB 7.5 Gev/c HMS spectrometer. The pair of identical Cosine Two Theta quads are an entirely new design with a large 60 cm warm bore and 13 Tesla/meter gradient. These 5 Tesla Quads provides focusing for particles from 1 to 12 Gev/c and have an integral gradient strength of 23.5 (T/M)M. The magnetic design including multipole strengths will be presented. The quadrupole cold mass uses a Stainless Steel shrink fit force collar, Titanium keys and a Copper stabilized super conductor consisting of a 36 strand surplus SSC outer cable wave soldered to a copper extruded substrate. This combination provides for a very conservative magnet that can be assemble with little or no tooling and a high degree of stability. The force collar mechanical analysis will be presented as well as details of the magnet cryostat.Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DOE-AC05-060R23177.Symmetric Notches in Yoke for primary beamline.Q2Q3SHMS 12 Gev/c Spectrometer : 18 Bend : 5.5 to 40 Angle Range : 5msr Solid AngleBender0.6 m LOA0.35 m Vertical aperture0.36 m Horizontal aperture3.5 Tons

    Dipole18.4 Bend / 3.81m LOA3.16 m Length Yoke2.50 m OD Yoke1.37 m ID Yoke140 Tons

    Q2/Q32.24 m LOA1.8 m Length Yoke2.0 m OD Yoke1.37 m ID Yoke60 Tons

    Q12.2 m LOA0.40 m Warm aperture18.0 Tons

    Force CollarTitanium KeysYokeThe magnet is designed as a two current sector cosine two theta coil with constant perimeter (CP) ends.The SHMS Q23 Quadrupole cold mass design uses an innovative coil preloading system which includes a shrink fit stainless steel force collar and Titanium keys. The JLAB Reference Design for the SHMS Q23 Quadrupole has the composite conductor insulated with half lapped Kapton tape and over wrapped with B-stage glass epoxy tape. The SHMS Q23 magnets will all be equipped with nominal 5000 Amp. vapor cooled current leads that are a no burnout design. A pair of these current leads was designed, built and tested at American Magnetics Inc. SHMS Q23 Longitudinal Section.Cryostat cylindrical assemblies.Inflated stainless steel cryo-panels as the LN2 shield Titanium keys are segmented and finger jointed along the length of the coil to avoid an overstress situation in the coil end turns.60 cm warm bore aperture. The leads can remain at a constant current of 4900 Amps for 11.3 minutes before reaching 200 milli Volts and 325 Kelvin.The nominal 13 Tesla/meter gradients are essential to achieve focusing and good resolution at momentum up to 12 Gev/c. These vapor cooled current leads are similar in construction to standard super conducting magnet optimized vapor cooled leads but they have a longer effective length and a larger conducting cross section. Identical Cosine Two Theta Quadrupole Pair.36 strand surplus SSC outer cableThe magnetic design of the SHMS Q23 Quadrupole has been designed using the TOSCA family of computer codes.SHMS Q23 Vertical Section.

    MagnetMT-20 Paper / SessionB0 / G0ApertureEFLMCurrent DensityA/cm^2Current (A)Energy(MJ)Peak CoilFieldTPeak Iron FieldTStekleyparameterBender4M022.95 T18 cm x 27 cm0.7528,9004,5000.33.693.241.46Q14M079.15 T/m40 cm2.15118,1003,1870.6282.704.610.57Q2/Q34M0913.1 T/m60 cm1.794,5005,0539.875.875.890.93Dipole1M04.7 T60 cm2.965,0534,50018.12.722.520.69