1. Status of QQXF cryostat
D. Ramos, C. Eymin, M. Moretti,

2. First things first: Present cryo layout
(R. Van Weelderen and D. Berkowitz, )
Note: We are free to choose the HX position but both must be at the same height

4. Some key spec’s and constraints
Alignment of the magnets by adjustment of the position of the complete cryoassembly through fiducials outiside the vacuum vessel (no adjustment of cold mass wrt to vacuum vessel after assembly)
Deviation in time of relative position between cold mass and vacuum vessel will be monitored
Motorised jacks with remote control to correct alignment of the cryoassembly (ZX plane only)
Transport constraints in the tunnel impose maximum width equal to present LHC cryostats: overal maximum 1072 mm / flange OD 1055 mm [C. Bertone, ]
Static heat loads comparable to the LHC arcs and MS
Columns under compression as cold mass support principle
Cold mass stands on at least three points at all times
Isostatic anchoring of vacuum vessel is an advantage

5. The QQXF as it looks today

6. Cryo piping diameters are first estimations, all to be confirmed by TE/CRG
Ø 1055 (upper limit for transport in the tunnel)
Ø 914x12
Maximised offset to open space for piping integration
GFRE support column w/ maximum diameter for dynamic stability
Two-piece column for acessiblity during assembly
Cold mass support assembly after cryostating

7. Reinforcing rings to prevent ovalisation
Fixed support post in the middle for better cold mass stability when handling
Longitudinal ribs for increased bending stiffness
Isostatic vacuum vessel supports (3 points) postioned for minimum cold mass bending

8. Tie rod for longitudinal loads
Isostatic anchoring Y X Z
“Vacuum force” (~80 kN, Q1 only)
(free,free,0)
(0,free,0)
(0,free,0)
Tie rod for longitudinal loads
(free,0,free)
Pressure end effect from cold mass interconnect
(depends on interconnect design)

9. Cryostating tooling: sledge on rails
The principle currently used in dipoles and long SSS
Cold mass supported on at least 3 points at all times
Minimum gaps for cold mass insertion and removal of sledges must be accounted for

10. Cold mass+shield lifted wrt nominal
Cryostating tooling
Cold mass+shield lifted wrt nominal
Sledge on rails
Lifting jack
Lifting jack
Support assembly
Tooling removal

12. Cold supports
The 60 K heat intercept position along the support post length optimized for minimum exergetic cost. For cooling at 60 K (Cs = 15) and at 1.9 K (Cc = 1000)
CENTRAL FIXED SUPPORT
SLIDING SUPPORT
Optimum at 37 mm for heat intercept at 60 K:
8.1 W at 60 K and 0.3 W at 1.9 K

13. Thermal Shield Thermal model FIXED SUPPORT SLIDING SUPPORT
5 mm thickness, supported at the heat intercepts:
No additional heat loads to 1.9K
Deformation under self weight ~2 mm
FIXED SUPPORT
SLIDING SUPPORT
0.28 W to 1.9 K
0.46 W to 1.9 K
Thermal model

14. Distance between cold mass supports
a = 3500 mm
length m
weight 22.5 ton
Minimum deflection at
a = 0.715xL/2 ≈ 3500 mm

15. Vacuum vessel No axial load “Vacuum force” (~80 kN, Q1 only)
Placement of jacks as optimised for minimum cold mass bending in layout version LHCLSXH_0010 AB: mm mm mm
2560
2560
No axial load
Cold mass weight: 22.5 ton mm mm mm
“Vacuum force” (~80 kN, Q1 only)

16. On-going work
Full integration 3D model: without it’s impossible to know where each pipe should be and how can they be connected (extremely compact integration)

17. On-going work Overal schematics including cryogenic piping and busbars
Development of management process for parts, configurations, assembly and logistics
Modelling of dynamic response to ground vibrations
Iterations as more data from cryo and powering becomes available

19. LHC triplet and dipole cross sections
Preference for column support posts but LHC layout cannot fit a larger cold mass plus pumping lines