Materials for Phase II collimators

LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 1

Rib Stiffener, why molybdenum

Stiffener material requirements: Minimise own thermal distortion Low CTE High thermal conductivity Minimise deflection by the force in the midpoint link High Young’s modulus X-deflection simulation Active part where most of heat is deposited tends to deflect due to thermal gradient

Stiffener

linked in a midpoint to limit deflection of the active part Link Shafts, fixed points LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 2

Stiffener, why molybdenum

550 500 450 400 Osmium, Commercial Purity, soft Rhodium, Commercial Purity, hard 350 300 Wrought PH stainless steel, Custom 455, H1000 Wrought austenitic stainless steel, AISI 304, annealed 250 200 150 Iridium, Commercial Purity, min 99.9%, soft Rhenium, Commercial Purity, soft Ruthenium, Commercial Purity, soft Tungsten, Commercial Purity, 25 micron wire Tungsten (f) Tungsten, Commercial Purity, annealed Molybdenum, 360 grade, wrought, stress relieved Al-C-fiber composites 100 Nickel-Iron Alloy, "INVAR", hard (cold worked) 50 Nickel-Iron Alloy, "INVAR", soft (annealed) 0 -15 -10 -5 0 5 10 15 20 25 30 35 Thermal conductivity / Thermal expansion coefficient 40 LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 45 50 55 3

Stiffener made of Mo, old monolithic version

LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 4

Stiffeners made of Mo, assembled by bolts and pins • How are the stiffners

Long plates 15 x 47 x 1100 mm ³ Thinner extremities Circular holes and slots Tolerance ~0.1 mm Threaded holes for cooling clamps Spacers Positioning system LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 Bolts and pins 5

Stiffener, raw material

• Overall dimension of long plate (mm) – ≥15 x 47 x 1100 • Standard dimensions by Plansee – 12.7 x 500 x 600 – 20 x 500 x 600 • Possibility of having customized production • Ideas to make it out of standard dimension plate for prototypes (4 ÷8 plates), eventually for series (~250 plates) – EB butt weld EBW EBW – Connect overlapped plates, bolted or riveted • Also – Spacers – Positioning system – Bolts and pins LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 6

Stiffener, machining

• Recommended machining parameters • Plansee as possible supplier of finished components – Tolerances achievable • Extremity holes • Positioning system elements – Do you see any other issue not mentioned?

LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 7

Cooling coil, interest of using molybdenum

Phase

1, implemented solution:

Phase 2

, increased energy deposition.

-Cooling capacity has to be increased - 6 x tubes ID8 mm - reduce contact thermal resistance -Geometrical stability has to be maintained - use material with optimised k/CTE

Ideal

solution:

Cooling coil back-casted in M-CD block

Brazing Brazing Contact CuNi GlidCop C-C LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 8

Cooling coil, interest of using molybdenum

• Cooling coil material for Ideal solution requires – Metallurgical compatibility with metal of the block • Avoid dissolution of the coil in the liquid metal • Avoid inconvenient inter-metallic phases at the interface – CTE matching with M-CD • Avoid distortion, residual stresses or debonding at the interface when solidifying and cooling from infiltration temperature • Gaps at the interface leads to poor thermal conduction and virtual leaks – Feasibility of the coil • Cooling coil materials believed to be good candidates from the first two points of view – For

Cu-CD

:

molybdenum

, niobium, tantalum – For

Al-CD

:

zirconium

(preliminary test program is in progress in cooperation with L. Weber EPFL including also stainless steel) LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 9

Silver, Grade 99.90, cast bar, hard (cold worked) 400 Cu-CD

Cooling coil, interest of using molybdenum

Electrolytic tough-pitch, h.c. copper, soft (wrought) (UNS C10100) 70/30 Copper-nickel, CuNi30Mn1Fe, soft (wrought) (UNS C71500) 350

• Molybdenum coil in Cu-CD block

300 – CTE Gold, Commercial Purity, min 99.5%, hard (cold-worked) – Feasibility of the coil Iridium, Commercial Purity, min 99.9%, hard Rhodium, Commercial Purity, hard Ruthenium, Commercial Purity, soft 200 Tungsten, Commercial Purity, annealed 150 Molybdenum, 360 grade, wrought, stress relieved Wrought aluminum alloy, 5052, O Wrought aluminum alloy, 5086, O 100 50 Osmium, Commercial Purity, hard Niobium, Type 2 (Commercial Grade Unalloyed Niobium) Tantalum, Commercial Purity (>99.7% Ta), cold worked Rhenium, Commercial Purity, soft Hafnium, Commercial Purity, min 97.0% Nickel-Iron Alloy, "INVAR", soft (annealed) Cobalt, Commercial Purity, soft (annealed) Nickel 205, Commercial Purity, annealed Carbon steel, AISI 1015 (annealed) Wrought ferritic stainless steel, AISI 430, annealed Antimony metal, Commercial Purity, "Regulus" 0 Zirconium, Unalloyed, Industrial Grade, wrought, "Zr702" Unalloyed titanium, Annealed -15 -10 -5 0 5 10 LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 15 20 25 Thermal expansion coefficient (µstrain/°C) 30 35 10 40

Cooling coil, interest of using molybdenum

Liquid Cu would dissolve Ti or Zr tube !

LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 11

Cooling coil, interest of using molybdenum

Mo, Nb and Ta have limited solubility in liquid Cu and do not form inter-metallic phases LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 12

Cooling coil, interest of using molybdenum

• • Feasibility of long intricate coil is a question mark.

– ID 8 mm x L 3800 mm – Bending radius as small as 18 mm Tests and trials – Tensile test at RT on molybdenum tube OD10xID8 (our CA1491024) • Rp0.2 = 570 MPa • Inner wall of the tube is oxidised Rm = 685 MPa • A ≥ 40% !!! but transversally very low ductility – Bending tests to be done at CERN workshop • What are your recommendations?

– Butt welding, your recommendations LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 13

Cooling coil, vacuum related constrains

• Avoid virtual leaks (confined volumes with low aperture that make long time to evacuate) • Avoid any welding or brazing between water and beam vacuum !  use of continuous seamless tube • Other solutions if the last constrain can be relaxed: – Cooling circuit machined in a block, closed by brazing or welding • Brazed to the main block • Back-casted inside the main block – Any other? – Any experience in similar large surface brazing LHC Collimators Phase 2 - Visit to Plansee 28th August 2008 14