WP3 Meeting – December the 10th 2015 H. Prin Quadrupoles and orbit correctors bus bars routing along the inner triplet string WP3 Meeting – December the 10th 2015 H. Prin

Outline Base line and Alternative schemes Internal vs External routing Pros and Cons Preliminary layout proposal Comparison with existing situation in the LHC DS Summary

Inputs Alternative scheme Base line Ramp down of the inner triplet magnets - J.-P. Brunet 22nd HL-LHC TC –30 April 2015 Alternative scheme Base line Ramp down of the inner triplet magnets - J.-P. Brunet 22nd HL-LHC TC –30 April 2015 Follow up of powering schemes for IT, Q4 and D1/D2 - M. Fitterer 22nd HL-LHC TC –30 April 2015 Triplet circuit protection with heaters and CLIQ - E. Ravaioli 5th HiLumi LHC-LARP Annual Meeting, 28 October 2015

Base line scheme Total Total External bus bars Internal bus bars Orbit Correctors Trim Q1 Trim Q2b Q1 – Q3 CLIQ Q2a-Q2b External bus bars 6 16 4 2 Total 1 2 1 3 8 1 4 1 1 2 2 8 Splices 50 2 5 16 2 3 22 Spliced on surface Spliced in the tunnel Internal bus bars 11 +5 9 +3 32 +16 2 30 +14 Total 1 2 1 2 3 8 6 2 8 1 6 2 8 2 8 +43 Splices 2 21 93 5 21 22 22

Alternative scheme Total Total External bus bars Internal bus bars Orbit Correctors Trim Q1 Trim Q2b Main Quads CLIQ External bus bars 1 7 16 6 2 Total 1 2 1 1 8 4 1 1 2 2 8 3 Splices 2 5 14 3 48 3 21 Additional trim on Q3 or Q2A could be installed on the warm par without further bus bar Orbit Correctors Trim Q1 Trim Q2b Main Quads CLIQ Internal bus bars 1 10 +3 32 +16 12 +6 4 +2 28 +12 1 2 1 2 8 3 1 6 Total 2 8 4 2 8 3 2 8 3 +39 Splices 2 5 18 20 21 21 87

Int./Ext. routing Pros and Cons External bus bars Internal bus bars Development Bus bars / cables Bus bars (Cables?) 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 Felix Magnet exchange Example for the alternate scheme Q3 exchange: Q2b exchange: Q2a exchange:  3 to 5 ICs to open  Less splices to be redone Or  only affected buses 20 splices or 5 disconnected/41 reconnected 18 splices or 17 disconnected/38 reconnected 12 splices or 19 disconnected/23 reconnected  2 ICs to open  All splices to be de-soldered/re-soldered 41 splices 38 splices 23 splices Interchangeability Q1Q3 and Q2AQ2B  Q1 and Q2a have to house all circuit present in respectively Q3 and Q2b to allow  Plugs or  restrictions between the external line and the cold mass volume Flexibility for cold test (Q1)  Possibility to test each MQXA individually  Additional bus bar needed to power each MQXA individually (48 to 50) (87 to 93)

Ext. routing preliminary layout proposal Worst condition: (without considering cables for D1 and CP) Free section 47.9 cm2 2 2/1/0 8 2/3 Orbit Correctors Trim Q1 Trim Q2b Q1 – Q3 CLIQ Q2a-Q2b To be developed: 34 NbTi strands Ø1.065 mm Cu/Sc ratio = 1.6 34 Cu OFE strands Ø1.065 mm 17kA or 34 NbTi strands Ø1.065 mm Cu Stabiliser equivalent cross section 4kA Present LHC 6kA cable: 13 NbTi wires Ø0.87 mm Cu/Sc ratio = 1.36 7 Cu wires Ø0.96 mm 2kA ?kA Present LHC 1kA cable: 1 NbTi/Cu wires Ø1.6 mm

Extracted from Delio’s talk on December the 3rd 2015 Ext. routing preliminary layout proposal Preferred locations from the cold mass point of view taking into account interconnections, standardization, spare policy and ergonomics : bus bar line in the cryostat in the vertical symmetry plane bus bar entrance in the cold mass in the vertical symmetry plane on top Heat exchangers on the bottom apertures of the magnets Extracted from Delio’s talk on December the 3rd 2015

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

Summary Base line and alternative schemes studies shows: Open issues: 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. Using cable rather than copper stabiliser soldered to Rutherford cable eases the expansion lyres design and integration. Alternate scheme is a bit less consuming in terms of bus, current leads and splices. One 2kA current lead for Q1 trim can be saved connecting it one warm side (no additional current lead in the alternative scheme for a Q3 or Q2A trim if required). Open issues: 17kA cable or bus bar profile has to be developed (cohesion in between SC and Cu wires or expansion lyres to be addressed). Cable for CLIQ depending on peak current intensity and time. New splices types configuration and tooling. Global interconnection integration on track, cryogenic requirements missing. Interconnection and integration is a challenge on which we are working hard to find solutions.

Spare slides

Present LHC SC cables specifications

Triplet flow diagram