1Oct. 16-17, 2013 HiLumi Conductor and Cable Review

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LBNL Cable Experience for HiLumi

HiLumi LARP/LHC Strand and Cable Internal Review

Oct. 16-17, 2013Oct. 16-17, 2013by Video by Video

D.R. Dietderich, A. Godeke, LBNL and

A. Ghosh, BNL

2Oct. 16-17, 2013 HiLumi Conductor and Cable Review

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Outline• Fabrication of a Rutherford cables• Review of the cable parameters for the LARP

– TQ/LQ, HQ/LHQ and QXF parameters• Strand damage scoring methodology

– What is it and how is it calculated. • Strand damage scores in cables for TQ/LQ, HQ/LHQ,

and QXF– Discuss TQ and HQ strand data and metallurgical

observations. • First QXF cable parameters are place in context with

the TQ and HQ parameters• Options for next generation of QXF cable

3Oct. 16-17, 2013 HiLumi Conductor and Cable Review

Cabling Objectives• Want to convert assemble of many stands

into a Rutherford cable for winding into a coils– Typically dipoles and quadrupole magnets

Side roll

4Oct. 16-17, 2013 HiLumi Conductor and Cable Review

QXF cable with Stainless Steel Core

Cable 1042Z-12

Thickedge

ThinEdge

5Oct. 16-17, 2013 HiLumi Conductor and Cable Review

Cabling Trade-offs • Minimize the amount of strand damage

– Less compaction – Can lead to mechanically unstable cable for coil winding– Developed cable winding score

• Increase mechanical stability of cable– More compaction and deformation of strands– More strand damage - Reduced critical current and RRR

(resistance increase of Cu matrix)– Developed strand damage Score

D.R.Dietderich

6Oct. 16-17, 2013 HiLumi Conductor and Cable Review

Cable Risk and Impact on Magnets – LBNL View

1. Strand stability (High risk)• Want high Is > 1,200 – RRR > 60 at kinks of extracted strands– RRR > 150 in strand to assist in getting RRR > 60 at kinks

• Should the RRR specification be increased to 175 to 200?

2. Stress sensitivity of cable with damaged strands (Unknown Risk) • Only data is for older generation wire

3. Cable winding stability (Medium risk)• Assume cable can be managed cable during coil winding

4. Strand Ic loss due to cabling, < 5 % (Low risk)– Ic of extracted strands at 12T ~850 A

– Ic at operation of 12 T ~400A

D.R.Dietderich

7Oct. 16-17, 2013 HiLumi Conductor and Cable Review

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Cable Design - Thickness

KSAngle

Use thickness “strain” at edges to determine parameters

MajorEdge

MinorEdge Mid

D.R.Dietderich

Aspect ratios of cablesTQ = 8.2HQ = 10.6QXF = 11.1 (9.0 mm)QXF = 12.2 (8.5 mm)

8Oct. 16-17, 2013 HiLumi Conductor and Cable Review

HQ Cable Experience

• Final parameter for HQ cable with 0.778 mm diameter strand

WidthThicknessKeystone from LBNL cable calculations

D.R.Dietderich

9Oct. 16-17, 2013 HiLumi Conductor and Cable Review

Suggested QXF Cable Parameters

• Mid-thickness = 1.525 mm +/- 0.010 mm• Width = 18.15 mm +/- 0.050 mm• K.S. angle = 0.55 deg. +/- 0.10 deg.

• Adjustable Parameters– Pitch Length = 109 mm +/- 3 mm – Annealed or un-annealed wire

• Should reduce residual twist in cables

• At this time LARP assumes that cables will need to be managed during coil winding– By using either the Berkeley winding block or CTD binder

D.R.Dietderich

10Oct. 16-17, 2013 HiLumi Conductor and Cable Review

Winding Score of Cable• Popped strand winding score of

cables1. Strand goes in easy and stays in

place2. Strand goes in easy but needs

handling to stay in place3. Strand goes in easy but will not

stay in place4. Difficult to put strand back into

cable, will not stay in place5. Can put strand or strands back

into cable

• The “Berkeley Block”

D.R.Dietderich

CCWCW

11Oct. 16-17, 2013 HiLumi Conductor and Cable Review

SQXF Practice Winding LBNL Oct. 2013

• 2 Objectives– One was to determine the fit of

prototype coil parts– Second was to test the winding

stability of a QXF cable with the target parameters

• QXF cable 1045Z-13• Insulated with 3 layers of E-

glass tape ~150 m• Winding tension 25-30 lbs• No popped strands

– Cable was stable– Used Berkeley Block– Did not try without block

12Oct. 16-17, 2013 HiLumi Conductor and Cable Review

Damage Scoring Methodology

• The strand in Image at left has 10 shear sub-elements plus ruptured barrier

• If it is a triple strand configuration at cable edge one would divide by 3.

• For a rectangular strand configuration one would divide by 2.

13Oct. 16-17, 2013 HiLumi Conductor and Cable Review

Cable in TQS03• Cable 982R

– RRP 108/127– Two pass cabling process– No stainless steel core– No sheared sub-elements

D.R.Dietderich

14Oct. 16-17, 2013 HiLumi Conductor and Cable Review

HQ Cable Damage Score

HQ-012 passcables

HQ-021 passCablesSS-core

D.R.Dietderich

15Oct. 16-17, 2013 HiLumi Conductor and Cable Review

Damage Score vs. OXF Cable Width for Pitch Length of 109 mm

D.R.Dietderich

18.47 mm calc. width for 109 mm

Need 17.95 mm width forWinding score of zero

1042Z-13 Target = 18.15 mm

RRP 108/127, ~1.50 mm thick

16Oct. 16-17, 2013 HiLumi Conductor and Cable Review

Critical Current (11T, 4.2K) vs. Width Ratio

-1.75 %Only 1.2% lossof Ic

D.R.DietderichMT23 July 17, 2013

RRP 108/127

17Oct. 16-17, 2013 HiLumi Conductor and Cable Review

RRR of QXF Strands Extracted from Cable

• Virgin round strand has RRR of 317 Ave. RRR of ES• RRR of kink (edge of cable) 150-160 , Cable width 17.94 mm

– Even with loss of RRR the Is was still > 1,200 A• Wire specification is 150. Should we increase it?

D.R.Dietderich

18Oct. 16-17, 2013 HiLumi Conductor and Cable Review

Cable 1046 Z with 0.90 mm Diameter Wire

0.85 mm

Cable 1046Z

1.63 mm thick18.15 mm wide0.53 deg. KS117 mm PL

Aspect ratios of cablesTQ = 8.2HQ = 10.6QXF = 11.1 (9.0 mm)QXF = 12.2 (8.5 mm)

19Oct. 16-17, 2013 HiLumi Conductor and Cable Review

Transverse Pressure on Nb3Sn Cable

TW 5 – 150 MPa

TW 5 – 0 MPa

Cables with little damage

Hans van OortThesis, U. Twente

20Oct. 16-17, 2013 HiLumi Conductor and Cable Review

Future Cable Modifications

0.85 mm diameter wireFine tuning of machine cableParameters not changed• Need RRP 132/169• Adjust strand tension• Annealed wire

– Reduce residual twist– Reduce shearing

• Modify mandrel trip• 3-6 months but not impact

on schedule

0.90 mm diameter wireMajor cross section change –

Thicker cable• Need RRP 132/169

– Used RRP 84/91 in R&D• Cable very stable with first

parameters – Winding score of 1– Damage score of 0-1.5

• Time 6 months with impact on magnet schedule

21Oct. 16-17, 2013 HiLumi Conductor and Cable Review

212121

Summary• Critical current loss is small and not a major concern

– However, past measurements on cables with sheared sub-elements showed they were more susceptible to transverse stress.

• RRR drop at edge of cable is a concern but should be manageable if RRR of wire is high– However, should attempt to reduce the number of sheared sub-

elements– Local RRR at kinks (edge of cable) dominates electrical stability

• May NOT have to improve cable mechanical stability– First 25 m practice winding at LBNL cable had no issues. – Used Berkeley block for winding

• Would like to consider thicker cable with 0.90 mm diameter wire to reduce aspect ratio of cable and sub-element shearing

D.R.Dietderich