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

2. 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

3. 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

4. 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

5. 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

6. 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 MPa provides the coil compression up to 17 kA in HQM (85% SSL).
HQ Mirror Assembly Rodger Bossert November 16, 2011

7. 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

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

9. 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

10. 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

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

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

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

14. 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

15. 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