QXF Cable, 1 st generation Giorgio Ambrosio, Paolo Ferracin Fermilab CERN QXF Video-meeting June 18, 2013 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 Work supported by the US LHC Accelerator Research Program (LARP) through US Department of Energy contracts DE-AC02-07CH11359, DE-AC02-98CH10886, DE-AC02-05CH11231, and DE-AC02-76SF00515

Outline S/LQXF Plan Cable R&D goals Cable R&D status Cable parameters for 1 st iteration Next steps June 18, 2013G. Ambrosio and P. Ferracin2

SQXF plan and schedule Coil fabrication CERN – Number of coils 1 Cu coil 1 practice + 5 real RRP coils 1 practice + 5 real PIT coils – After SQXF01 – Fabrication steps Winding + curing + reaction + impregnation – Fabrication time ~100 days (5 months) per coil 1 coil produced every 2 months LARP – Number of coils 1 practice 1 mirror + 4 real RRP coils – Fabrication steps FNAL: winding + curing LBNL: reaction + impregnation BNL: reaction + impregnation – Fabrication time ~100 days (5 months) per coil 1 coil produced every month 09/04/2013 G. Ambrosio and P. Ferracin3 Sequence: CERN will start with RRP coils – SQXF1 magnet will include the first available four RRP coils produced by the two “production lines” – With the current plan, either 3 LARP + 1 CERN or 2 LARP + 2 CERN Slide presented at the LARP-HiLumi Collab Mtg April 8-10, 2013

SQXF plan and schedule 09/04/2013G. Ambrosio and P. Ferracin4 Slide presented at the LARP-HiLumi Collab Mtg April 8-10, 2013

SQXF & LQXF Schedule 09/04/ | 2014 | 2015 | 2016 | 2017 | LQXF1 LQXF1b LQXF2 LQXF3 & 3b SQXF coil in mirror SQXF1 SQXF1b SQXF2 SQXF2b Slide presented at LARP Project Reviw June 11, 2013

S/LQXF Cable plan and schedule Original plan (Collaboration meeting in Frascati) – Set cable dimension by 1 March year before winding begins New deadline (Collaboration meeting in Napa) – June 1, months before winding begins – Coil parts fabrication time via standard machining: 6-8 months LARP Project Review on June 11, 2013 – Cable parameters for 1 st iteration decided on June 8, If rapid prototype is used (baseline option) – Coil parts fabrication time: 4-5 months Copper wedges take about the same time – So, a second cable iteration in September could be implemented from the beginning June 18, 2013G. Ambrosio and P. Ferracin6

Outline S/LQXF Plan Cable R&D parameters and goals Cable R&D status Cable parameters for 1 st iteration Next steps June 18, 2013G. Ambrosio and P. Ferracin7

Cable Parameters and Goals Parameters: – 0.85 mm strands – 40 strands – Stainless steel core (coverage > 60%) Goals: – Cabling degradation < 4-5% – RRR after-cabling > 150 – I s > 3* I op – Mechanical stability (no popped strands w/o tools) – No sub-element shearing at cable edges (in micrographs) June 18, G. Ambrosio and P. Ferracin

1042Z- 10

Cable 1042Z‐13

Sub-element shearing Is this a problem? 1) Let’s look at “good” magnets – Operating at constant current at > 80% of SSL 2) Let’s look at magnets with issues June 18, G. Ambrosio and P. Ferracin

HQ02a Ramp Rate Dependence Preliminary quench data by G. Chlachidze No quench 170 T/m, 82% SSL at 1.9k, 92% SSL at 4.5K

Strand Damage Score D.R.Dietderich LARP-CERN Meeting May 21, 2013

Damage score for HQ cable 996R-B (RRP 54/61) D.R.Dietderich LARP-CERN Meeting May 21, – no sheared sub-element

HQ Cable Damage Score HQ-01 2 pass cables HQ-02 1 pass Cables SS-core D.R.Dietderich LARP-CERN Meeting May 21, 2013

June 18, G. Ambrosio and P. Ferracin

Cable in TQS03 Cable 982R – RRP 108/127 – Two pass cabling process – No core – No sheared sub-elements Note: LQ cable had parameters very similar to TQ cable

Preliminary observations: The best magnets built by LARP have cables with no shearing in subelements  The confidence in using Nb 3 Sn technology for HL- LHC is mostly based on magnets with this feature  Can we have the same confidence if we change the criteria for cable design? Are there “good” Nb 3 Sn coils/magnets which have consistent shearing in subelements? – I have not found any so far… – Please, show a demonstration if you have it ! June 18, G. Ambrosio and P. Ferracin

Issues in magnets Testing Nb 3 Sn magnets we have seen limiting behaviors, which we cannot completely explain – Reverse ramp-rate dependence Many examples … – Enhanced instability Ex: LQS02 What coil yield should we expect during production if we select a cable with shearing planes in each x-section? June 18, G. Ambrosio and P. Ferracin

Risk analysis Based on data collected so far adopting a cable with sheared subelements in each x-section is a risk – ~10 coils needed for understanding impact on coil yield First feedback by end of 2014 Full feedback by end of 2015 – Impact on schedule can be significant if we have to change cable design by the end of 2014 – Mitigation plan: develop smaller cable with no sheared subelements, that can fit in same coil x-section Smaller strands, 39 strands, … As demonstrated by HQ02 June 18, G. Ambrosio and P. Ferracin

Outline S/LQXF Plan Cable R&D goals Cable R&D status - LARP Cable parameters for 1 st iteration Next steps June 18, 2013G. Ambrosio and P. Ferracin21

22 Base Line Cable for 0.85 mm Diameter Strand Preliminary Parameters 40 Strands 0.85 mm diameter w = mm t = 1.50 mm KS angle = 0.65 deg. Tolerance on parameters? Expand R&D Range 40 Strands 0.85 mm diameter w = mm t = mm KS angle = deg. With/without SS Core Core widths of – 8mm (~50%) – 12.7 mm (~80%), Standard – 15.8 mm (~97%) D.R. Dietderich LARP-CERN CM20 April 9, 2013

Round Wire Critical Current of Extracted Strands D.R. Dietderich LARP-CERN CM20 April 9, 2013

RRR of Cables Round Wire D.R. Dietderich LARP-CERN CM20 April 9, 2013

RRR – Local Variation D.R. Dietderich LARP-CERN CM20 April 9, 2013

05/06/2013 Paolo Ferracin26

Damage Score - QXF 1044Z-6 32/3 + 2/3 = /4 = D.R.Dietderich LARP-CERN Meeting May 21, 2013

Damage Score - QXF 1044Z- 7 14/5 = 2.8 9/3 = 3 D.R.Dietderich LARP-CERN Meeting May 21, 2013

1042Z-10

Cable 1042Z‐12

Damage Score vs. Cable Width for PL of 109 mm mm calc. width for 109 mm Need mm width for Winding score of zero 1042Z-13 Cables 1045Z -10,11 Comment facet size about the same

April 9, 2013D.R. Dietderich CM20 32 Winding with a Block Place block on cable and slide into turn Keep block as near to pole as possible while rotating table As cable bends around turn strands deform into the shape of the pole All QXF cables can be wound w/o popped strands by using this tool

Outline S/LQXF Plan Cable R&D goals Cable R&D status - CERN Cable parameters for 1 st iteration Next steps June 18, 2013G. Ambrosio and P. Ferracin33

Cable R&D Width : 17.8 mm Width compaction C w = Mid-thickness : 1.50 and 1.53 mm Keystone angle : 0.65 degree Pitch length : 113 mm (17.5 o ) and 125 mm (16 o ) Cw larger than its value for the FRESCA2 cable (- 4.6) but smaller than its value for the cable for the dipole DS 11 T (- 2.6). A. BallarinoNapa, LARP Meeting, 9 April 2013

Cable R&D PL=113 mm, 1.50 mm 3.9 % (Ic max. 5.8%) PL=113 mm, 1.53 mm 2.9 % (Ic max. 6.6%) PL=125 mm, 1.50 mm 2.7 % (Ic max. 4.4%) PL=125 mm, 1.53 mm 0.52 % (Ic max. 2.4 %) Mid-thickness Pitch 4.3 K 12 T 4.3 K 12 T 4.3 K 12 T 4.3 K 12 T A. BallarinoNapa, LARP Meeting, 9 April 2013

Cable R&D Average Ic degradation = 1.8 % 4.3 K 12 T A. BallarinoNapa, LARP Meeting, 9 April 2013

Cable R&D T=4.3 K Extracted strands –three Is > 1000 A A lot of margin… A. BallarinoNapa, LARP Meeting, 9 April 2013 Ic (A) B (T)

What are the results obtained up to now with the most compacted cables having a width of 17.8 mm The 17.8 mm wide core cables, with and without a core, fabricated with RRP strands are not enough mechanically stable for winding with a keystone angle of 0.65 o, a mid- thickness of 1.50 mm and a pitch length of 109 mm or 117 mm. The critical current degradation is in average around 2 % The RRR values on extracted strands are greater than 130, The stability current at 4.3 K is greater than 1200 A, although there are damage sub-elements in the strands located at the edge of the cable. Mid-thickness ~ 1.50 mm and PL = 113 mm

Comparison of PIT and RRP core cables (17.8 mm, PF = 109 mm, 1.50 mm) HE89AHUI109150F HO90AHUI109150F No shearing seen through the sub- elements of the PIT cable. Shearing clearly seen in the RRP strand located at the cable edge.

Susana Izquierdo Bermudez40 1. CERN winding test set up (2/2) GEOMETRY 1: POLE INNER LAYER GEOMETRY 2: BIG SPACER INNER LAYER GEOMETRY 3: POLE OUTER LAYER

Susana Izquierdo Bermudez41 4. Counter-clockwise (unfavorable) direction QXFB1042z12, GEOMETRY 1 (POLE INNER LAYER)

H160C123A, GEOMETRY 2 (BIG SPACER INNER LAYER) Counter-clockwise (unfavorable) direction

Winding test example (with tool) 05/06/2013Paolo Ferracin43

Winding test example (with tool) 05/06/2013Paolo Ferracin44

Winding test example (with tool) 05/06/2013Paolo Ferracin45

Winding test summary 06/06/2013Paolo Ferracin46

Summary - I According to preliminary data, it seems that, with cables in the range mm, it is possible to obtain: – I s > 3* I op – RRR> 150 – Cabling degradation ~2% June 18, G. Ambrosio and P. Ferracin

Summary - II Sheared (broken) subelements are observed in all the RRP cables so far The number of sheared subelements reduces moving from 17.8 to 18.3 mm width – Although it does not disappeared completely at 18.3 mm No sheared subelements observed in PIT cables June 18, G. Ambrosio and P. Ferracin

Summary - III Many winding tests performed by LARP and CERN – Width ranging from 17.8 to 18.3 mm All cables can be wound with a winding tool Without the winding tool, only some PIT cables gave positive results – 1 sample of 17.8 mm – 3 samples of 18.1 mm June 18, G. Ambrosio and P. Ferracin

1 st iteration cable parameters June 18, G. Ambrosio and P. Ferracin

Next steps Continue development of cables with 1 st iteration parameters – Pitch length and other parameters Develop cable for 2 nd iteration – Could be implemented in first SQXF coils if rapid- prototyping will be used Plan QXF conductor review around mid of September 05/06/2013Paolo Ferracin51