DOE/SC Status Review of 12 GeV SHMS HB Magnet: Update since Oct 2015 Eric Sun Paul Brindza Steve Lassiter Mike Fowler October 25-26, 2016

Outline Overview Key Parameters Three-stage Test Plan Test Results of Stage 3 Magnetic Field Mapping Conclusion

Cryogenic control reservoir SHMS Q1 beam cutout Front opening HB beam cutout Vacuum vessel Warm iron Suspension link

Key Parameters of HB Parameter Unit Design Value 11 GeV current A 3900 Test current 4000 Pole Gap (warm) mm 350 Number of turns per pole turn 90 Stored energy at 3900 A MJ 0.19 Field at 3900 A (11 GeV) T 2.5 Max field in coil at 3900 A 3.2 Self-inductance at 3900 A H 0.025 Current density at 3900 A A/mm2 22.5 Overall physical length of magnet m 1.16 Magnet weight ton 6.8 Length of SSC cable in each coil 234.4 Total helium volume in magnet and CCR m3 0.118 Insulation thickness between turns 0.28 Cross section of coil mm×mm 13.3×130 Cross-section of SSC cable 11.68×1.156 Cu:NbTi ratio of SSC cable   1.8 Dump resistor (final)  0.024 Effective field length 770 Integral field strength at 3900 A Tm 1.97 Set pressure of relief valves (He and N2) atm (gauge) 4 Set pressure of rupture discs (He and N2) 5

Eddy Current on Thermal Shield T6 is a temperature sensor, which can be used to correlate simulations and measurements.

Three-Stage Test Plan First Stage – low current tests (up to ~400 A) Low dump resistor and warm (218 K) thermal shield lead to less eddy current and thus less displacement and stress due to Lorentz force. Second Stage – medium current tests (up to 2000 A) Projected displacement and stress were acceptable at 4000 A if a 0.24 ohm dump resistor and a warm (218 K) thermal shield were used. Third Stage – high current tests (up to 4000 A) Successful ramped up to 4000 A and fast discharged from 4000 A. Behaved normally after multiple fast discharges from high currents. Measured and simulated temperatures matched well.

Test Results of Third Stage Measured (based on T6) vs simulated average temperature rises. The dashed line, the simulated temperature at T6; the solid line, the measured. 218 K thermal shield and 0.024 ohm dump resistor.

Training Curve HB magnet was able to reach 3900 A or 4000 A for the last six ramp-ups. No scope was wired for Event 42. But it was believed Event 42 was caused by PSU.

Magnetic Field Mapping - Equipment LakeShore XHGT-9060 hall probe was used. Hall probe was manually moved.

Magnetic Field Mapping – Results (3900 A) Measured (blocks) and simulated (solid red line) magnetic field along the central tube. The measured field at Location 27 was 2.53 T; the Tosca-simulated field, 2.54 T.

Conclusion HB Magnet was successfully ramped up to 4000 A and safely fast discharged from 4000 A. HB magnet was well trained now. Measured and simulated magnetic fields match well. HB magnet is done!