Presentation on theme: "Q1 for JLAB’s 12 Gev/c Super High Momentum Spectrometer S.R. Lassiter, P.B. Brindza, M. J. Fowler, S.R. Milward, P. Penfold, R. Locke Q1 SHMS HMS Q2 Q3."— Presentation transcript:
Q1 for JLAB’s 12 Gev/c Super High Momentum Spectrometer S.R. Lassiter, P.B. Brindza, M. J. Fowler, S.R. Milward, P. Penfold, R. Locke Q1 SHMS HMS Q2 Q3 Bender Dipole Abstract— The reference design for the first Quadrupole magnet of TJNAF’s Super High Momentum Spectrometer (SHMS), Q1, is presented. The SHMS is a dQQQD design that will be capable of resolve particles up to 11 Gev/c in momentum. Q1 follows the successful design of the High Momentum Spectrometer’s (HMS) Q1, that of an elliptically shaped super ferric yoke, conformal mapped window frame coil, bath cooled coil design. The primary differences between the two designs being in the choice of superconducting cable and an overall longer magnet length. A single stack of surplus SSC Rutherford NbTi cable replaces the original four stack copper stabilized conductor used in the HMS’s Q1. The Q1 will have warm bore diameter of 400 mm, produce field gradients up to 9.1 T/m with an effective length of 2.14 m. Test coil windings progress will be given as well as reports on forces, conductor stability and energy margins. ParameterQuantity Conductor Dimensions x mm Filament size0.402 m Cu:SC Ratio``` Ic (4.5K and 5.3T)7846 Ic / Io (4.5K and 5.3T)2.46 Kilo Amp Turns /Pole255 A.T Critical Current Margin4,659 A Kapton Thickness0.102 mm B-stage Epoxy Thickness0.127 mm Voltage Discharge500 V Hot Spot temperature41 K ParameterQuantity Pole Radius0.250 m Warm Bore0.402 m Axial Cryostat Length2.2 m Yoke Length2.03 m Current Density18,100 A.T/cm 2 Kilo Amp Turns /Pole255 A.T Turns / pole80 Operating Current A Stored Energy0.628 MJ Inductance123.7 mH Magnet Weight18 tons Parameter`Quantity Gradient Max9.15 T/m Effective Field Length2.151 m Peak Yoke Field4.61 T Peak Coil Field2.7 T Field at Pole (R=0.25 m)2.27 T Momentum Range2 to 11 Gev/c Integral Harmonic N=4 % of N= to % Integral Harmonic N=6 % of N= to 0.21% Integral Harmonic N=10 % of N= to -.10 % Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DOE-AC05-060R SHMS Parameters Q1 Magneto-Static Results 2.32 m Yoke length Cold Mass Side View Current Lead End Cold Mass Assembly Notch for beamline extends to Helium Outer vessel. Ø 0.40 m Warm Bore Cross Sectional View Outer Vacuum shell Outer He Vessel SS Yoke Band Inner He Cylinder Ln2 Shields / MLI Not Shown Quadrant view of yoke lamination and Coil clamping Fixture 80 Turns of Rutherford cable Coil clamping/tensioning Fixture Mechanical Configuration Photos from Scientific Magnets LTD. Trail Winding Burnout Proof 5KA Current Leads The current leads will have a 9 W heat load to the 4K budget at full current. Scientific Magnetics studied the mechanical implications of increasing the magnet length by 15% over the original HMS Q1 and determined that sufficient margins existed to safely handle the expected loads. Magnetic Forces calculated by JLAB using TOSCA and loaded into a two dimensional FEA model. Largest stress is below 41MPa. Integral Harmonics for the SHMS Q1 Field Modulus in the Yoke and The Coil Field Gradient at maximum current Yoke, Coil and Cryostat lengths are given for comparison. Plots starts at the center of the magnet and extends out one end. Maximum Field in the yoke occurs along the pole edges. Nominal Field within the yoke is 2.4 T Holes in the yoke served multiple purposes: 1.He cooling passage. 2.Multipole tuning feature. 3.Tie bolts holes for stacking and compressing the Yoke laminations.