1. JLAB CLAS12 Torus Structure The cold mass is composed of 6 coils, each inside a coil case, joined together at the inner radius by a hub and at the outer radius by 2 reinforced I-beam rings. The vacuum vessel is composed of 6 vacuum vessel jackets joined at the inner radius to 6 seal plates, 2 end discs and 1 warm bore tube. The 6 vacuum jackets are also joined together by 2 box beam rings. The cold mass is supported by the vacuum vessel through 24 in-plane struts connecting each coil case to a vacuum jacket and 24 out-of-plane struts connecting the I-beams to the box beams. The vacuum vessel is supported by 4 legs mounted to the floor. 1 Figure 1: JLAB CLAS12 Torus

2. 2 Coil case and vacuum jacket – old design

3. 3 114 11.5 7.8 22 7.8 Coil case and vacuum jacket – new design

4. Vacuum jacket Figure 3: Vacuum jacket 4

5. Subassembly Figure 4: Torus subassembly showing in-plane fiberglass struts 5

6. Coilcase cross-section Figure 3: Coil case cross section 6 Figure 5: Coil case

7. Coilcase coordinates 8 Figure 7: Coilcase coordinates

8. Vacuum jacket coordinates 9 Figure 8: Vacuum vessel coordinates

9. Cold mass hub 10 Figure 9: Cold mass hub

10. Out-of-plane struts 11 Figure 10: Cold mass I-beam, vacuum vessel box beam and out-of-plane fiberglass struts

11. Seal plates, end discs & warm bore tube 12 Figure 11: vacuum vessel jackets joined to seal plates, end discs and warm bore tube

12. Coil blocks to apply EMF Figure 12: Torus coil subdivided in 78 volumes. EMF forces computed with Opera3D/Tosca are applied on each volume on the ANSYS model. 13

13. Material properties 13 Figure 11: JLAB CLAS12 torus magnet mode: vacuum vessel supported on 3 legs ComponentMaterialFormTensile strength Yield strength Temp.Reference Vacuum vessel SS 304Plate annealed 545 Mpa 79 ksi 228 Mpa 33 ksi 25 C Marks’ Standard Handbook for mechanical engineers CoilcaseAL6061 T6Plate annealed 25-50 mm 310 Mpa 45 ksi 291 Mpa 42 ksi 25 C Handbook of materials for superconducting machinery AL6061 T6Plate annealed 25-50 mm 483 Mpa 70 ksi 380 Mpa 55 ksi 4 K Handbook of materials for superconducting machinery Cold mass hub AL5083 H321 Plate320 Mpa 46 ksi 222 Mpa 32 ksi 25 C Handbook of materials for superconducting machinery Plate670 Mpa 97 ksi 300 Mpa 43 ksi 4 K Handbook of materials for superconducting machinery

14. Material properties 14 ComponentMaterialFormTensile strength Yield strength Temp.Reference LegsA500 Grade BTube 7x7x0.5 410 Mpa 58 ksi 290 Mpa 42 ksi 25 C Manual of steel construction

15. Struts 15

16. STRUTS 16

17. Stut tensioning method 17 1Assemble 6 subassemblies per TORUS IDR Chapter E. 2Keep all IP struts slightly tightened to 1 kN to restrain and stabilize the coldmass in Z (after phase 5). 3Gradually tighten together: Big ring OOP struts 6,17 from 0 kN to 49 kN to support coldmass weight Keep very low load on all other big ring OOP struts Small ring OOP struts to 7,20 from 0 kN to 15 kN to support coldmass weight All other small ring OOP struts to 13 kN to prevent coldmass tipping (after phase 5) 4Gradually tighten all IP struts to 10 kN. 5Release bolts holding coldmass to vacuum vessel in coil 4,3,5 (lower coils) and 2,6,1 (upper coils). 6Adjust OOP struts to set cold mass X, Y, pitch and roll 7Gradually tighten Big ring OOP struts 6,17 from 49 kN to 62 kN All other Big ring OOP from 0 kN to 13 kN 8Adjust in-plane struts to set cold mass Z and yaw

18. ANSYS model 14 Figure 13: JLAB CLAS12 torus magnet mode: vacuum vessel supported on 4 legs

19. 19 Detector loads

20. 20 Detector loads

21. ANSYS model 17 Figure 19: Vacuum vessel jackets connected to seal plates, end discs and warm bore Figure 18: Side leg

22. ANSYS model 18 Figure 20: Cold mass structure Figure 21: Cold mass structure

23. ANSYS model 19 Figure 22: Cold mass structure: front viewFigure 23: Coil case to I-beam connections

24. ANSYS Load cases 45 Load caseDescription 1 Winding loads (100 lb winding tension + 2000psi/14MPa bladder pressure), a y =1g, Room Temperature a)OOP big ring struts 6,17 @ 49 kN OOP small ring struts 7,20 @ 2 kN All other struts loose b)+13 kN to all OOP big ring struts +13 kN to all OOP small ring struts All IP struts loose c)Case b + all IP struts @ 10 kN d)Case c + detector loads e)Case d & bladder at 0 psi 2 Winding loads, vacuum loads, a y =1g, Room Temperature, strut loads, detector gravity 3 Winding loads, vacuum loads, a y =1g, 4 K, strut loads, detector gravity 4Winding loads, vacuum loads, a y =1g, 4 K, Lorentz Forces, strut loads, detector gravity

25. ANSYS Load cases 46 Load caseDescription 5-xWinding loads, vacuum loads, 4 K, Lorentz forces, strut loads, detector loads 1)a x =+0.1g, a y =+1.1g, a z =+0.1g + Detector EQ 2)a x =+0.1g, a y =+1.1g, a z =-0.1g + Detector Gravity 3)a x =+0.1g, a y =+0.9g, a z =+0.1g + Detector Gravity 4)a x =+0.1g, a y =+0.9g, a z =-0.1g + Detector Gravity 5)a x =-0.1g, a y =+1.1g, a z =+0.1g + Detector Gravity 6)a x =-0.1g, a y =+1.1g, a z =-0.1g + Detector Gravity 7)a x =-0.1g, a y =+0.9g, a z =+0.1g + Detector Gravity 8)a x =-0.1g, a y =+0.9g, a z =-0.1g + Detector Gravity