Briefs submitted for the TB to approve Tesla’s long lead items: Cold Mass Forging Super conductor wire

1. Briefs submitted for the TB to approve Tesla’s long lead items: • Cold Mass Forging • Super conductor wire

2. Technical Board approval for The Cold Mass forging Location of the Cold Mass in the AFC module

3. Dimension of the Cold Mass as specified in the AFC Technical Spec. Dimensions and material of the Cold Mass Coil size:- Latest agreement on the conductor size with Tesla is:- Formvar insulated:- 1.57 x 1.00mm With a 0.1mm thick interlayer insulation, this makes the coil size:- ~ 210 x 84mm As long as the forging provides a generous machining allowance, there shall be no risk in this respect. Material:- We specified Aluminium T6061 Tesla propose the same material. Material fully compliant!

4. Forging dimension as specified in Tesla’s purchase order

5. Profile of the Tesla Bobbin forging Cold mass profile as per AFC Technical Spec Average machining allowance is 9 – 10mm on both surfaces. This is acceptable!

6. Details of Tesla’s procurement related QA / QC documents are in Attachment 1 and are summarised in the table below

7. Super-conductor wire What was in the AFC Module Conductor Spec Conductor size: 1.65x1.05 over insulation Coil width 210mm Thickness 84mm Turns/layer 127 Layers 76 Helium volume 9.5 litres/coil Inter-layer insulation 0.1mm Ic=760A(5T,4.2K) What Tesla offers and requires our approval:- Conductor size: 1.52 x 0.95mmFormvar insulated:- 1.57 x 1.00mmwith 0.1mm interlayer insulation Coil width ~ 210mmCoil thickness ~84mm Turns / layer:- 132No. of layer:- 76 Helium volume 9.5 litre / coil Ic=686A(5T,4.5K) Obviously Tesla’s proposal is different to that specified in our AFC technical specification

8. Material composition and details of the proposed super-conductor wire Type F 174 Dimension bare 1.52 x 0.95 mm² Formvar insulated 1.57 x 1.00 mm² Consisting of 174 NbTi filaments In a Cu-matrix Ratio Cu : NbTi abt. 4.0 : 1 Core conductor with Nb-barrier Core Alpha abt. 0.45 Corner radius > 0.20 Filament diameter abt. 48 µm Ic at 4.2 K; 0.1 µV/cm, 5 T – 686 A RRR > 80 A meeting was held on the25th of July and following Elwyn Baynham’s assessment of the proposed wire size (see Appendix 2), we have recommended the acceptance of the type F174 wire; Tesla confirmed that the above change does not have any implication on cost or delivery schedule;

9. Attachment 1 The following documents are submitted with this review brief:- Word document:- “Final Customer Approval” by Tesla PDF document:- “Purchasing Plan” by Tesla PDF document:- “General Purchasing Specification” by Tesla

10. Attachment 2 Elwyn Baynham’s preliminary assessment of the MICE specified super-conductor wire with that proposed by Tesla

11. Attachment 2 P1 of 4 AFC Module Conductor Spec Spec Conductor 1.65x1.05 over insulation Ic=760A(5T,4.2K) Coil width 210mm Thickness 84mm Turns/layer 127 Layers 76 Helium volume 9.5 litres/coil Inter-layer insulation 0.1mm

12. Attachment 2 P 2 of 4 • AFC Module Conductor Spec • Conductor Options • Stay with Original Specification 1.65x1.05 with 0.1mm inter-layer insulation • Tesla tolerance specification =/- 0.01mm • Turns/layer – 127 turns/layer should be maintained as specified • At nominal conductor size the coil width will be 209.55mm • This is an allowance of 3.5 microns /turn for conductor spacing • Tesla should confirm that in their experience this is sufficient margin to wind 127 turns in each layer • At conductor max size 1.65+0.01mm it is not possible to fit 127 turns in the layer • Tesla should indicate what they propose to do in this case to meet the specification • Increase the coil channel width – what would be required? • Contd on next slide

13. Attachment 2 P 3 of 4 • AFC Module Conductor Spec • Conductor Options - contd • Stay with Original Specification 1.65x1.05 with 0.1mm inter-layer insulation • Tesla tolerance specification =/- 0.01mm • Coil thickness • 76 layers at 1.05+0.1mm interlayer insulation thickness ( we believe the interlayer insulation requirement was accepted by Tesla) • Spec was 76 layers at 84mm thickness • For this conductor option at nominal size 76 layers x 1.15 =87.4mm • For this conductor at max size 76 layers at 1.16 = 88.2mm • Consequences/impact • The increased thickness will move the coil centre radially outwards and this would require an increase in the operating current of ~ 1Amp ( no real effect) • The increased radial thickness would reduce the Helium volume in a single coil by 20% at the max size – this we are concerned about relaxing at this stage because we do not have yet the detailed design calculations from Tesla to confirm heat loads, coil losses during ramping etc • Both of these issues were discussed at the meeting in September 07 and communicated to Tesla in a memo at the beginning of May 2008 • At both instances we requested that Tesla should give their assessment of the coil thickness build up and possible variations

14. Attachment 2 P 4 of 4 • AFC Module Conductor Spec • Conductor Options 2 • Change the conductor size to1.57x1.00 with 0.1mm inter-layer insulation • Tesla tolerance specification =/- 0.01mm • Ic=686A(5T,4.5K) • Turns/layer – 132 turns/layer should be considered as new spec • At nominal conductor size the coil width will be 207.24mm • This is an allowance of 20 microns /turn for conductor spacing • At max conductor size the coil width will be 208.56mm • This is an allowance of 10 microns /turn for conductor spacing which seems realistic – Tesla should comment • Coil thickness • Coil thickness is maintained to specification • Margins spreadsheet shows that the operating point is 75% along the load line with temperature margin ~ 1.5K • Operating current would be 200.3 A for 200Mev/c