1. Quadrupoles and orbit correctors bus bars routing along the inner triplet string MQXF Workshop at CERN– February the 3 rd 2016 H. Prin With acknowledgements to A. Ballarino, C. Scheuerlein, D. Ramos Duarte, J.-P. Tock and P. Fessia for their comments and contributions MQXF Workshop at CERN– February the 3 rd 2016 H. Prin With acknowledgements to A. Ballarino, C. Scheuerlein, D. Ramos Duarte, J.-P. Tock and P. Fessia for their comments and contributions

2. Base line scheme Internal vs External routing - Pros and Cons Busbar vs cable - Pros and Cons Bus technology towards Routing Preliminary layout proposal Comparison with existing situation in the LHC DS Summary 2 Outline

3. Base line scheme Orbit CorrectorsTrim Q1Trim Q2bQ1 – Q3CLIQQ2a-Q2b DFX

4. Base line scheme Orbit CorrectorsTrim Q1Trim Q2bQ1 – Q3CLIQQ2a-Q2b Total 2 2 5 5 16 2 2 3 3 22 50 External bus bars Internal bus bars 2 2 5 5 21 22 +43 93 Total Splices Splices Spliced in the tunnel Spliced on surface

5. External bus barsInternal bus bars Splice quantity  > 80% Short to ground on a circuit or electrical fault Cable exchange between the DFX and concerned interconnect  Cryoassembly exchange Possibility to alternate the impedances on the main circuit: Q2a and b on the return bus bar  Not really needed according to Mr Circuit Magnet exchange  3 to 5 ICs to open Less splices to be redone Or  only affected buses 2 ICs to open  All splices to be de-soldered/re-soldered Interchangeability Q1  Q3 and Q2A  Q2B  Q1 and Q2a have to house all circuit present in respectively Q3 and Q2b to allow Cryogenic Scheme  Plugs or  restrictions between the external line and the cold mass volume Flexibility for cold test (Q1, Q3) on surface Possibility to test each MQXA individually  Additional bus bar needed to power each MQXA individually Int./Ext. routing - Pros and Cons (48 to 50)(87 to 93)

6. Busbar (stabilized Rutherford cable) Round cable Development & experience Strand and cable availability with low external field  Cable development and validation Protection (current distribution) Proven technology Soldered stabilizer  To be studied and proven Fabrication place Cable availability if LHC cable retained CERN in the busbar factory  To be developed with industry Integration stability 3D flexibility  Containment of electromagnetic forces to be studied Installation Preferably during cold mass assembly  Cartridges could be envisaged Opportunity to be installed in the tunnel from one connection point to the other Expansion loops Well known (lyre profiles) but  integration volume (radial and longi) Insulation  To be settled according existing developments Splices  To be developed (existing experience on the 6kA circuits)  Preparation in case of reconnection (ALARA) QA Process (Splices validation @warm)  To be developed 6 Busbar vs Cable - Pros and Cons

7. ++ Splices types and validation + Well known technology  - Longitudinal space for expansion loops - Entire cold mass disassembly in case of bus bar problem (may be solved with cartridges?) - More splices - Surrounding field -- Cryoassembly exchange in case of short -- Ergonomic for splices and ALARA principle ++ Longitudinal space gain for the expansion loops playing with cable flexibility + Easier bus exchange in case of problem  - More splices - Splices types and validation ++ Splices types and validation + self magnetic field  ? Expansion loop integration  -- Installation -- Rigidity ++ Less splices ++ Installation in the tunnel ++ Cable exchange in case of a short  ? Magnet exchange ? Plugs or restrictions  - Splices types and validation - Cable development 7 Cable Busbar Bus technology Internal External Routing Bus technology towards Routing

8. 8 Orbit CorrectorsTrim Q1Trim Q2bQ1 – Q3CLIQQ2a-Q2b Worst condition: (without considering cables for D1 and CP) Free section 47.9 cm 2 Ext. routing preliminary layout proposal To be developed: 34 Nb-Ti strands Ø1.065 mm Cu/Sc ratio = 1.6 34 Cu OFE strands Ø1.065 mm Present LHC 6kA cable: 13 Nb-Ti wires Ø0.87 mm Cu/Sc ratio = 1.36 7 Cu wires Ø0.96 mm Present LHC 1kA cable: 1 Nb-Ti/Cu wires Ø1.6 mm or 34 Nb-Ti strands Ø1.065 mm Cu Stabiliser equivalent cross section

9. 9 Ext. routing preliminary layout proposal Extracted from Delio’s talk on December the 3 rd 2015 Preferred locations from the cold mass point of view taking into account interconnections, standardization, spare policy and ergonomics : 1.bus bar line in the cryostat in the vertical symmetry plane 2.bus bar entrance in the cold mass in the vertical symmetry plane on top 3.Heat exchangers on the bottom apertures of the magnets Worst case btw Q2A-Q2B Section 2.53cm 2 without insulation nor EM forces restraints or guiding pieces Worst case btw Q3-DFX Section 5.37cm 2 without insulation nor EM forces restraints or guiding pieces

10. 10 Present situation in the LHC DS N-Line N-Line cable partial extraction between 2 MBs See Procedures: LHC-QBBI-IP-0030, 31 and 32 used during LS1 for MB exchanges 42 - 600A wires 3 – 6kA cables Bus Bar line for the HL-LHC triplet (scaled) Metallic hose to be avoided

11. 11 Today 20162017 Decision Validation Procurement Feasibility study 6 Months 10 Months Price inquiry and Prototype cable production 3 Months Tests Procurement process 4 Months Series production Splices developments Technical specification 1 Month Steps for 18kA Nb-Ti cable development up to production 2018 QA Splices According to discussions with A. Ballarino

12. Up to 22 buses to be housed (only for the quads and the orbit correctors, CP and D1 to be added and integrated in between Q3 and DFX). Using an external routing saves up to 40% splices, simplify consolidation in case of short and simplify the standardization in between Q1-Q3 and Q2A-Q2B. Cable eases the expansion lyres design, integration and installation. It is more appropriate to external routing. But it has to be developed as well as the splices procedures and tooling (~2 years required). Copper stabiliser soldered to Rutherford cable bus bars is a very developed and mastered technology both for production and splices connections. LHC cable could be used and is available. This design is not suitable for long dimensions and require volume for the expansion loops. It does not seem to be very suitable for external routing. 12 Summary

13. 13 Conclusions Global integration work is going on taking into account environment constraints and requirements (cryogenics, vacuum, beam instrumentation…). Despite the last longitudinal increase of the interconnection length it is not straightforward to design. An important part of the integration work is dedicated to the electrical bus integration taking into account the technology and the related constraints (splices quantity and types, ergonomics, ALARA principal…) as well as the bus installation. Orbit correctors, trims and CLIQ circuits can be routed externally using existing sc cables currently used in the LHC. For 18 kA circuits, the “busbars” solution shall be kept as base line until a “cable” type solution has been developed and validated. Internal routing is considered inside the cooling holes but an external solution is not excluded today, extensive integration work is ongoing. Situation has to be studied at the level of the Corrector Package and the D1. The different intervention scenarios will considered to determine the intervention time and the shielding possibilities in order to support the different choices.

14. 14 Alternate scheme is a bit less consuming in terms of bus, current leads and splices The routing seems more adequate for internal routing. Comments on alternative scheme

15. The HiLumi LHC Design Study is included in the High Luminosity LHC project and is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404.

16. Back-up slides

17. Alternative scheme Orbit CorrectorsTrim Q1Trim Q2bMain QuadsCLIQ Total Total +39 Orbit CorrectorsTrim Q1Trim Q2bMain QuadsCLIQ 2 2 5 5 14 3 3 3 3 21 18 20 21 48 87 2 2 5 5 21 External bus bars Internal bus bars Additional trim on Q3 or Q2A could be installed on the warm par without further bus bar Splices Splices

18. 18 Magnetic Field in the MQXF cooling holes Courtesy of Susana Izquierdo Bermudez

19. 19 Courtesy of Francois Eymin Piping integration – latest version

20. Present LHC SC cables specifications

21. 21 Triplet flow diagram

22. 22 Courtesy of Carlos Ortiz Ferrer Entire scheme taking into account CP and D1