HQ Mirror Assembly R. Bossert LARP Collaboration Meeting November 16-18, 2011

Introduction & Motivation Fermilab has implemented the “Magnetic Mirror” design for both dipoles and quadrupoles, as an efficient way to optimize and/or “pre-test” Nb3Sn coils. It is an efficient way to test new coil designs and features in a significantly shorter time period than would be necessary for full quadrupoles. Based on positive experiences gained using dipole and quadrupole mirror structures to test coils of 1m, 2m and 4m long we can: test individual coils under operating conditions similar to those of the real magnet. reduce the turnaround time, material and labor costs. scale-up Nb3Sn coil technology. HQ Mirror Assembly Rodger Bossert November 16, 2011

HQ Mirror Assembly Rodger Bossert November 16, 2011 Mirror Design TQC TQM HQM The quadrupole mirror designs TQM (for 90-mm TQ coils) and HQM (for 120-mm HQ coils) are based on the mechanical structure of the LARP technology quadrupole collar (TQC) series. Three coils, stainless steel collar blocks and preload control spacers were replaced by the magnetic mirror blocks and spacers. HQ Mirror Assembly Rodger Bossert November 16, 2011

HQ Mirror Assembly Rodger Bossert November 16, 2011 HQ Mirror Concept Horizontal “side shims” are placed here G-10 and Kapton midplane shims Side “ear” Iron Mirror Block Stainless Skin Iron Yoke HQ Mirror Assembly Rodger Bossert November 16, 2011

HQ Mirror Assembly Rodger Bossert November 16, 2011 Mirror Magnetic Flux Distribution at 20 kA Tesla 12 10 8 6 4 2 14 HQ Mirror Magnetic Flux Distribution at 20 kA HQ Magnet Magnetic Flux Distribution at 20 kA HQ Mirror Assembly Rodger Bossert November 16, 2011

HQ Mirror Coil Stress Distribution 300 K 4 K 4 K, 14 kA, 17 kA At quench current the azimuthal Lorentz force in the mirror is ~30% lower than in the quadrupole model => lower coil prestress needed. The coil stress after assembly of 120-130 MPa provides the coil compression up to 17 kA in HQM (85% SSL). HQ Mirror Assembly Rodger Bossert November 16, 2011

HQ Mirror Assembly Rodger Bossert November 16, 2011 HQM01-3 Coil Features Two HQ mirrors have been tested. Construction of a third is beginning. Mirror Coil # Strand Cable Cable Insulation Azimuthal Space for Expansion (L1/L2) Axial Gap (mm/m) Previous HQ Coils RRP w/o core S2 glass sleeve 1.9%/1.9% 1 HQM01 HQ12 RRP 54/61 SS core 5.4%/4.6% HQM02 HQ13 7.6%/6.3% 2.75 HQM03 HQ14 RRP 108/127 6.8%/6.8% 4 TABLE 1 COIL SPECIFIC FEATURES HQ Mirror Assembly Rodger Bossert November 16, 2011

HQM Coil CMM Measurements HQ13 before HQM02 at 736mm from lead end One square = 100 microns (4 mils) 100 µm 130-160 µm radially 60 µm HQ Mirror Assembly Rodger Bossert November 16, 2011

HQ Mirror Assembly Rodger Bossert November 16, 2011 HQM Shim System Upper Yoke G-10 and Kapton midplane shims Horizontal “side shims” Stainless protective shell. Transverse coil preload and support is provided by stainless steel skin. Axial preload and support is provided through end bolts in the end plates. HQ Mirror Assembly Rodger Bossert November 16, 2011

HQ Mirror Assembly Rodger Bossert November 16, 2011 HQM Coil Strain Gauges Azimuthal active gauges Axial active gauges Temperature Compensators HQ Mirror Assembly Rodger Bossert November 16, 2011

HQM01 Data During Pressing HQ Mirror Assembly Rodger Bossert November 16, 2011

HQM01 during Construction HQ Mirror Assembly Rodger Bossert November 16, 2011 12

HQM01 during Construction HQ Mirror Assembly Rodger Bossert November 16, 2011 13

HQM01-2 Mirrors Assembly Summary Cored cable. Space increased for coil expansion by increasing reaction cavity size by 1000 um (40 mils). Completed with 132 MPa azimuthal preload. End load 10 kN each end. Tested April 2011. HQM02: Cable without core. Space increased for coil expansion by removal of one turn. Increased longitudinal space in cavity from HQM01. Completed with 130 MPa azimuthal preload. End load 10 kN each end. Tested September 2011. HQ Mirror Assembly Rodger Bossert November 16, 2011 14

HQ Mirror Assembly Rodger Bossert November 16, 2011 HQM03 Mirror Status Coil HQ14 has been shipped to Fermilab. 108/127 cable No core. Cable size reduced to accommodate larger space for reaction. Further increase of longitudinal space in reaction cavity. HQ14 will be measured this week, and assembly will begin November 28. Preload goals identical to HQM01 and HQM02. Completion of magnet is expected by end of calendar year 2011. Testing will take place late January/early February. HQ Mirror Assembly Rodger Bossert November 16, 2011 15