Coil working group video-meeting P. Ferracin, J. C. Perez, S. Izquierdo Bermudez, X. Sarasola January 29, 2014

Agenda Coil electrical checks Winding test updates Nb 3 Sn-Nb-Ti splice: procedure and fixture Single vs. double NbTi leads Wire for instrumentation 29/01/2014 P. Ferracin2

29/01/2014 P. Ferracin3

Product description 1.1 Technical specification of the capacitive discharge generator Other requeriments: HV Lemo connector or two separate terminals for power output connection. BNC analog output of voltage. Non – inductive resistive divider for output voltage measurement. Capacitor bank discharge with time constant between 30 s and 60 s. Re-arm pulser. Emergency button which cuts mains and short circuits capacitors. Switch off command to discharge the capacitor bank in less than 1 s. Graphical plot of output current vs time or output voltage vs time. USB port for data storage. Output voltage7000 VmaxOutput capacitance2 μFMinimum load inductance0,5 mHPeak current of the discharge100 AmaxDinamic range100 V to 7000 V Setting resolution±10 VDeviation between setpointand output value±1% at Vmax increasing linearly up to ±10% at Vmin 29/01/2014 P. Ferracin4

Splicing and tinning tooling 23/01/2014 J.C. Perez5 The same tooling will be used for tinning and splicing using MOB 39 as flux and solder 96/4 Tin/Silver

Splicing tool assembly sequence for tinning and cutting operations 23/01/2014 J.C. Perez6 Cutting Tinning Tool assembly Clamping Courtesy of Nicolas Peray

Splicing configuration 23/01/2014 J.C. Perez7

Flux and soldering alloy used at CERN Main issue: presence of an oxide layer after reaction. How to remove this oxide layer? – Activated fluxes: Improve solderability ×But the residue left can lead to corrosion ×Essentially banned at CERN – In SMC and RMC the splicing region is cleaned with a soft stainless steel brush MOB 39 offers the best results of the non-activated fluxes tried at CERN. Preferred soldering alloy: Sn 96.5% Ag 3.5%, T m = 221 o C Sn96.5Ag3.5 + MOB 39 is used for: – Pretinning the NbTi and Nb3Sn cables – The actual Nb 3 Sn/NbTi splice 29/01/2014 P. Ferracin8

Instrumentation & Quench heaters wires 23/01/2014 J.C. Perez9 Instrumentation wires: AXON reference HH2619 LH Conductor diameter mm (0.15 mm 2 ) Conductor composition: Copper silver plated External wire diameter: 0.95 mm Wire insulation: polyimide tape wrapped (glued with a thin layer of fluoopolymer) Nominal voltage : 1000V AC Axon voltage test: (2*U N )+1000V= 3 kV Approx. price: 2220 €/km Quench heaters wires: AXON reference H 1619 L Conductor diameter 1.5 mm (1.34 mm 2 ) Conductor composition: Copper silver plated External wire diameter: 1.8 mm Wire insulation: polyimide tape wrapped (glued with a thin layer of fluoropolymer) Nominal voltage : 600V AC Axon voltage test: (2*U N )+1000V= 2.2 kV Approx. price: 4500 €/km

Updated status and possible plan 1.28/10-01/11, fabricate short plastic poles (BEND poles), 1 set 2.28/10-01/11, Wind/cure outer layer short Cu coil 3.28/10-01/11, Update BEND inner/outer layer spacers after short winding test /11, Update ROXIE/CAD inner/outer layer spacers /11, Fabrication inner/outer layer BEND/ROXIE plastic spacers (v3) for FNAL /12, Insulation of CERN Cu cable /12, Fabrication inner/outer layer ROXIE plastic spacers (v3) for CERN 8.06/01-17/01, Fabrication inner/outer layer ROXIE/BEND plastic spacers (v3) for LARP /01, LARP to wind 1st short coils (ROXIE LE/BEND RE) with plastic parts /01, CERN to wind 1 short coils (ROXIE) with plastic parts /02, Update ROXIE (v4) /02, LARP to wind 1sd short coils (ROXIE RE/BEND LE) with plastic parts /02, Update BEND (v4) and decision /12, Delivery 6 poles to FNAL /01, Delivery of 2 sets metal spacers (arrival 07/02/14) for CERN and FNAL /02, Launch procurement 1 set of metal spacers for FNAL /02, Launch procurement 5 sets of metal spacers for FNAL/CERN (market survey completed) /02, Launch the price inquiry for 3 sets of CERN poles /02, arrival of 2 sets of Cu wedges 29/01/2014 P. Ferracin10

CERN W&C tooling status All delivered and cleaned Next week assembly 29/01/2014 P. Ferracin11

CERN tooling status R&I tooling – Parts ordered Step files requested Nb-Ti lead related parts on hold – Expected in late March (1 reaction set) – end of April (the rest) CERN wedges – Expected by mid-March Work in progress to meet tolerances requirements 29/01/2014 P. Ferracin12

Susana Izquierdo Bermudez Field in Nb3Sn-Ti splice region 13 Magnetic Yoke & Pad =975 mm Non magnetic Pad =350 mm Non magnetic Pad = 225 mm

Susana Izquierdo Bermudez Field at the ends decay very quickly The fringe field of the magnet is negligible compared with the self-field of the interconnection 14 Field in Nb3Sn-Ti splice region Problems can be decoupled  Field in the interconnection can be computed analytically and/or with a very simple model I (kA)B p (T) (ANSYS*) B p (T) (ROXIE**) “Recycling” a very simple model I did for the LHC main interconnections * Does not consider iron and the rest of the leads ** Does not account for current flow in between cables Design Parameter for Nb-Ti lead: B p = 2T Current distribution

Nb-Ti leads parameters (from Luc) Strand: mm LHC strand, 1.6 Cu/SC ratio Cable: 34 strands, width of mm and a mid-thickness of 1.92 mm. Field – In the nominal conditions (17.5 kA) we expect a field in the splice area of ~1.5 T – In the short sample condition (21.2 kA) we can say that the field in the splice area the field is ~2 T Critical current – Luc estimated approximately what would be the critical current of the cable 17 kA at 10 T and 1.9 K as high as 60 kA at 2 T and 1.9 K (to be confirmed) 44 kA at 2 T and 4.2 K 39 kA at 3 T and 4.2 K 19/12/2013 P. Ferracin15

Comparison End Spacer Heat treatment

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