1. MKD stack upgrade MKD generator meeting Viliam Senaj 23/06/2015

2. Effect of return rod displacement RR displacement [mm]0 Present situation 5101520 Inductance stack [nH]132141149157165 Inductance MKD total [nH]2.6822.6912.6992.7072.715 Voltage @ 7 TeV [kV]2929.0629.129.1429.19 Emax [MV/m]2.92.531.911.591.4 Trise increase [ns]0+4+ 8+12+ 15

3. Solution with return rods displaced by 20 mm Return rod displaced by 20 mm Araldite insulation of RR Modified top insulator – upper tube included Reduced diameter of 4 upper HV deflectors and full insulation by araldite HV contact insulated by araldite Modified 4 top snubber capacitors – araldite tube around instead of HV deflectors

4. Solution with return rods displaced by 20 mm

5. Time plan Drawing of machining plans ~ 2 weeks Procurement of raw material for 3 switches ~ 2 months Machinning ~ 4 weeks Assembly ~ 3 days Test of single stack in HV case up to 40 kV ~ 1 week Test inside generator ~ 6 months

6. Magnet current @29 kV o vs 20 mm displacement (132 vs 165 nH)

7. Main dividers 2 x 100 MΩ

9. Main dividers 2 x 100 MΩ - solution

11. HV divider 10 x 5 MΩ, top deflector

12. HV divider 10 x 5 MΩ – solution

13. HV contact region - today

14. HV contact region - solution

15. Final solution

16. MKD E/B2 freewheel signal

17. MKD schematics