Cryo-assembly design D. Ramos, V. Parma, C. Mucher, H. Prin, M. Souchet, J. Hrivnak, M. Moretti, L. Mora, F. Savary, L. Gentini Review of the 11T Dipoles at Collimator Section for the HL-LHC

Outline Recalling the concept Bypass cryostat and interfaces with collimator Support layout and management of thermal contractions Interconnect design Interfaces with beam vacuum Vacuum vessel specifications Thermal shield design Line N cable pulling Instrumentation Current leads Drawings for management of mechanical interfaces

Cryo-assembly: 3 modules to replace one MB Cryo-assembly composed of 3 independently aligned modules: 2 cryo-magnets + 1 bypass cryostat Collimator mechanically decoupled from the cryostat The cryo-assembly is interchangeable with any MB irrespective of location (see cold mass presentation for implications on circuits) No changes required to nearby magnets

The integration approach K2 M2 V2 W Y M1 M3 E C’ V1 K1 X N QRL side

X Y M2 M1 W M3 E N C’ Cold beam line Dedicated collimator design. One collimator design fits both beam lines W Collimator alignment is not impacted by vacuum vessel displacements during pump down M3 E N Collimator supported directly on the concrete slab C’

Bypass cryostat Installed before the collimator Creates a room temperature vacuum sector in the continuous cryostat Aligned as any other machine cryostat

TCLD Collimator - Interfaces Courtesy L. Gentini TCLD Collimator - Interfaces New design of actuation system in order to comply with integration constraints ‘Quick’ CF flange for removal and connection of collimator Pre-aligned support stand Integrated expansion joint with RF bridge for alignment and installation clearance Jaw “active” length: 600 mm Flange to flange length: 1080 mm

Cryostat support layout Cold mass fixed point near the centre: for small contractions at the intermediate interconnects and minimum change wrt replaced MB Distance between jacks shared with DS magnets Q11, Q10, Q8: 3705 mm Gives nearly ideal cold foot distance for minimum cold mass deformation: 3430 mm (estimated less than 0.1 mm sag even with a 10 mm thick shell) W-sleeve on the downstream interconnect cannot be fully open but still acceptable for interconnecting work

Interconnecting the 11 T cold masses Universal expansion joints between cold masses: Negligeable interconnect forces No static heat loads through supports Line X Lines M1, M2 Line N CWT Line E Line V

Expansion joint design   Busbar line M universal expansion joint Heat exchanger line X universal expansion joint (external) Thermal shield line E universal expansion joint Aux. busbar line N universal expansion joint Design pressure [bar] 20  4 22 Test pressure [bar] 25 5.2 27.5 Temperature [K] 300 - 2 300 – 2 300 – 50 Axial displacement [mm] 16 (-6/10) 23 (-8/15) 30(-10/20) Inner diameter [mm] 88 54.4 80 50 Outer diameter [mm] 101 73.4 99.5 70 Convolution pitch [mm] 9.1 4.47 6.52 9 Number of convolutions 4+4 6+6 Number of plies 3 2 Thickness of on ply [mm] 0.4 0.3 0.35 Axial stiffness [N/mm] 504 124 285 172 Column squirm pressure (EN 13445) [bar] 77 37 39 24 In-plane squirm pressure (EN 13445) [bar] 66 19 49 29 Fatigue life (EN 13445) [cycles] 686 623 467 192 Fatigue life (EJMA) [cycles] 2065 1875 1404 579 Circumferential membrane stress [MPa] 31 5 28 Meridional membrane plus bending combined stress [MPa] 135 89 198 214 Stainless steel 1.4435 (316L) Proof stress Rp1.0 [MPa] 260 Allowable circumferential stress f=Rp1.0/1.5 [MPa] 173 Allowable meridional stress Kf.f [MPa] 520 See Edms doc. 1569107

Cold to wam transition and cold beam line Supplied and assembled by TE-VSC Compact design Copper cold bore, conduction cooled 1.9 K Thermalisation at the extremities 85 mW to 1.9 K level See Q. Deliege, WG Meeting on Cryostats for HL-LHC magnets #8, https://indico.cern.ch/event/497468/ Heat loads for 2 CWT’s: ~ 5.5 W to 5 K level < 12 W to 50-65 K level

Vacuum vessel for cryo-magnet See technical specification LHC-QBAH-CI-0001, Edms doc. 1539976 Cylinder: P355NL2 low carbon carbon steel with impact tests at -50 C Flanges: 1.4307 (304L) stainless steel Vibration stress relieving after welding followed by precision machining of interfaces Abrasive blasting plus high pressure water jet degreasing Leak tightness 10-9 Pa m3 s-1 Painted external surfaces for corrosion protection Reguirements identical to present LHC cryostats

Vacuum vessel for bypass The same vacuum vessel can be used for collimator either on beam 1 or beam 2 Stainless steel 1.4307 (304L) stainless steel Vibration stress relieving after welding followed by precision machining of interfaces Abrasive blasting plus high pressure degreasing Leak tightness 10-9 Pa m3 s-1 Mechanical analysis: J. Hrivnak, WG meeting on cryostats for HL-LHC magnets #6, https://indico.cern.ch/event/486351/

Thermal shield bottom tray and cold support posts See drawing folder Edms doc. 1573465 Sliding support post bolted to the cold mass and guided on vacuum vessel with alignment key Fixed support post bolted to the cold mass and to the vacuum vessel Standard aluminium to stainless steel transitions Stainless steel piping Using existing extruded aluminium extrusions GFRE support posts available in stock Standard C’ line pipework

Thermal shield Two cooling points at the extremities Thermal shield for bypass cryostat made from AW 1050 Welding during assembly excluded due to risk of fire on MLI: Bolted assembly with invar washers End plates supported on three slotted holes at 120º to accomodate radial thermal contraction Downstream plate supports with play for axial thermal contraction Thermalisation to line E at two points Thermal shield in the 11T cryo-magnets and interconnects are identical to MB cryostats Heat load to 50-65 K [W] Thermal shield support 18 V-line support 1.3 Radiation 8.7 Total 28 See H. Hrivnak, WG Meeting on Cryostats for HL-LHC magnets #10, https://indico.cern.ch/event/507182/ Two cooling points at the extremities

Pulling of line N cable New line N routing adds two bends as it goes through the bypass cryostat 50 m long cable pulling test was performed on a full scale mockup to ensure feasibilty in the tunnel Feasibility demonstrated: No additional splices required. Temporary tooling necessary at the interconnect flanges to prevent metal edges from damaging the cable insulation

Instrumentation Two IFS connector boxes for cold mass instrumentation (see cold mass presentation) IFS boxes of existing LHC design Thermometers for cold tests: Line E (lowest temperature) Bypass thermal shield (highest temperature) 4x DN100 KF for feedthroughs on prototype vacuum vessel No thermometers on machine cryo-assemblies

Current leads for the trim circuit 2x 250 A conduction cooled leads Only one location is possible Similar to a Dipole Corrector Feedthrough in the SSS (EDMS 328999) RT copper cables  towards power converter Gas cooled leads not possible both for lack of space and cryogenics Preference for conduction cooled leads Local solution: applicable everywhere in the LHC

Mechanical interface layout

Jack positions in the tunnel Longitudinal constraint Lateral constraint

Handling and transport interfaces

Conclusion Integration with magnet, collimator and vacuum has been concluded. The design of the prototype cryostat is done. Assembly drawings and procedures are being drafted. The design of the bypass cryostat is nearly finished. The magnet cryostats follow the LHC design basics. One configuration designed to fit all possible locations in the LHC (with local trim). No changes required to nearby magnets. Interconnecting work done in the tunnel takes advantage of existing procedures thanks to many LHC standard components and tooling.

A. Lechner et al. - 3rd HiLumi LHC-LARP Meeting – Daresbury, Nov. 2013 Integration in IR7 A. Lechner et al. - 3rd HiLumi LHC-LARP Meeting – Daresbury, Nov. 2013