1 LARP Magnet Program G. Ambrosio Many slides from (with a few modifications): Jim Kerby for the LARP Magnet Collaboration 25 October 2006 Rad-Hard Insulation Workshop Fermilab – Apr 20, 2007

2 Mission Statement: The US LHC Accelerator Research Program enables U.S. accelerator specialists to take an active and important role in the LHC accelerator during its commissioning and operations, and to be a major collaborator in LHC performance upgrades. In particular, LARP will support U.S. institutions in LHC commissioning activities and accelerator science, accelerator instrumentation and diagnostics, and superconducting magnet R&D to help bring the LHC on and up to luminosity quickly, to help establish robust operation, and to improve and upgrade LHC performance. Furthermore, the work we do will be at the technological frontier and will thereby improve the capabilities of the U.S. accelerator community in accelerator science and technology to more effectively operate our domestic accelerators and to position the U.S. to be able to lead in the development of the next generation of high-energy colliders.

3 US LHC Accelerator Research Program Magnet Systems Provide options for future upgrades of the LHC Interaction Regions Primary Focus: Demonstrate by 2009 that Nb 3 Sn magnets are a viable choice for an LHC IR upgrade –The major issues: Nb3Sn technology, consistency, bore/gradient (field), length –Three phase approach 1.Predictable and reproducible performance  TQ models (1 m, 90 mm aperture, G nom > 200 T/m, B coil > 12 T) 2.Long magnet fabrication  LQ models (4 m, 90 mm aperture, G nom > 200 T/m, B coil > 12 T) 3.High gradient in large aperture  HQ models (1 m, 90+ mm aperture, G nom > 250 T/m, B coil > 15 T)

4 Technological Quadrupoles Two mechanical designs are under development Same coils / Aperture = 90 mm / Gradient > K 2 layers Filler Keys 4 pads Bladder Yoke Aluminum shell TQC: using collars Collar laminations from LHC-IR quads 1 st time applied to Nb 3 Sn coils TQS: using Al-shell Pre-loaded by bladders and keys 1 st time applied to shell-type coils

5 TQ Coil Design and Fabrication Design features: Double-layer, shell-type One wedge/octant (inner layer) TQ01: OST-MJR strand, 0.7 mm TQ02: OST-RRP strand, 0.7 mm 27-strand, mm width Insulation: S-2 glass sleeve Winding & curing (FNAL - all coils)Reaction & potting (LBNL - all coils)

6 “Baseline Strand” Rod Re-Stack Process, RRP 54/61 Design –0.7mm diameter –Filament diameter ~ 70  m –Jc in the range of A/mm 2 at 12T –RRR of stabilizer Cu > 100 –low field stability current I s ~ 1000 A and higher depending on reaction time/temperature 70  m

7 Conductor (2) 54/61 RRP conductor is in house 60/61 RRP under evaluation - larger filament spacing, same Cu/non_Cu ratio (Cu = 47%) 108/127 or 120/127 - More thinner subelements  more stable (flux jumps) 1. 60/61 restack with spaced SE’s

8 S-Glass Sleeve application on Cable S-Glass sizing removal S-Glass is 875 F Teflon Tube S-Glass Sleeve S-Glass: Palmitic Acid application Insulation Procedure

9 Winding & Curing After winding a ceramic binder is applied (painted) on the coil, the binder is cured at 150 C for 30 minutes (becoming a strong bonding agent), Coils are ready for heat treatment (~650 C in argon)

10 Impregnation  Choice of epoxy CTD-101K and EPON828/DMP30 (used in Main Injector Magnets) were tested CTD-101 K was chosen because: the pot life is much higher than DMP-30, very good penetration inside the coil good mechanical properties

11 Goal By the end of 2009 LARP should deliver a successful Long Nb 3 Sn Quadrupole It will be a Proof of Principle that Nb 3 Sn is a viable option for the LHC luminosity upgrade  In order to have a complete Proof of Principle we will have to address this question: “Can this magnet withstand the expected radiation dose?”  We should be able to reply either: “Yes it can, and we have data to demonstrate it” “No it cannot, but we have tested a TQ with an insulation/impregnation scheme that can withstand the expected dose” Plan A Plan B

12 Plan A  Identify the most critical parameters of TQ-like magnets that can deteriorate under high radiation dose –Depending on material and magnet design –Share/tension, swelling, thermal conductivity …  Plan tests of these properties before and after high dose irradiation (a few different doses)  Challenges: –Energy spectrum and dose: reactors, beams (size?), LHC? –Need hot cell? –Need to keep samples cold?

13 Plan A possible results OK, the present insulation/impregnation scheme can withstand the expected dose We can optimize the absorbers so that it can withstand the expected dose No way, We need a plan B!

14 Plan B Goal: select a material for coil impregnation that can withstand the expected max dose and is compatible with LARP Nb 3 Sn coil fabrication technology –Possible candidates: cyanate ester, mixture with epoxy, matrimid, other polyimides… –Evaluate mechanical, electrical and thermal properties Literature, cable stack measurement –Evaluate compatibility with Nb 3 Sn coil fabrication technology Good impregnation, binder compatible, …

15 Time frame Plan APlan B FY07Develop plans, schedule, cost Select alternative material FY08 Q1-Q2 Prepare samples and fixtures FY08 Q3-Q4 Irradiation & tests FY09SQ and/or TQ

16

17 Questions Develop plan to arrive to these answers: “Can this magnet withstand the expected radiation dose?”  We should be able to reply either: - “Yes it can, and we have data to demonstrate it” - “No it cannot, but we have tested a TQ with an insulation/impregnation scheme that can withstand the expected dose”

18 Appendix

19 939R 946R Facet Size Determination 

20 LR/LM/LQ: Long Magnet Fabrication Long Racetrack (4m) – Coil fabrication scale-up based on well-understood sub-scale coils – Explore length scale-up of coils in shell-based support structure – LR design complete – BNL practice winding, installation of necessary tooling underway, oven shipped this week – Tech transfer to BNL w/ SRS01 test successful Mirror dipole scale-up via FNAL core program – 2m practice coils under reaction, winding of 2m coils underway  4 m coils to follow Long quadrupole (LQ) – 3.6 m quadrupole based on TQ cross- section—initial coils and tooling designs in study

21 Beyond TQ: High Gradient Quadrupoles HQ1 HQ2 Goals: Explore field and stress limits Feedback to IR optimization The reference cross-sections were selected taking into account stress considerations:

22 LHC-IR Prototype High Gradient in a Large Aperture LHC IR Upgrade Prototype – Aperture: mm – Gradient > 200 T/m – Design will depend on results form previous parts of the LARP program LHC performance in first years Feedback from AP experts Example: 4-layer, G= T/m