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1Oct. 16-17, 2013 HiLumi Conductor and Cable Review
11
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
2
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
7
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