Some naïf ideas on cryostats

2-2-2015, BNL-LBNF meeting

D.Mladenov, M.Nessi

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concrete floor

cavern

warm cryostat

cryogenics + services

Cavern cross-section

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LArSS GTT membrane

GTT

isol

ation

SS skin 6-10 mm

Carbon steel structure ~300 mm

Carbon steel belt ~800-1000 mm

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Inner dimension (liquid): • L = 33.50 m• W = 15.10 m• H = 14.00 m

outer warm structure

SS skin

possible supports to the cavern wall

LAr = 9’915 tons

belts

Warm CryostatTop cap&Detector supports

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Grid: 0.8m x 0.8m

18.10 m16

.70

m

support to the floor: h=0.3 mLength 36.5 m

Outer structure : configuration

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Materials used (warm vessel):

Carbon steel : S355J2Quantity : ~450 tons (to be optimised)

SS plates : 304LQuantity: ~150 tons

Mechanical properties :

Yield strength: 355MPa Tensile strength: 500MPa

With good low-temperature structural performance

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The outer structure

The stainless steel plates (form inside)

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2 x 4’500 tons2 x 2’000 tons

On the long wallsOn the short walls

Loading 1. Hydrostatic pressure on the walls 2. Overpressure (100mBars)

2 x 470 tons2 x 210 tons

+ 500 tonsOn the cap

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Results1. Deformations [mm]

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Results1. Stresses [MPa]

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Remarks :

From the mechanical point of view it looks feasible Supports towards the cavern to increase safety factors

To go further it would need a real engineering study and a optimization of all parameters

Cost ? ~ 12.3 M- membrane + isolation material + engineering: ~ 2.5 M- membrane installation: ~

4.0 M (20 FTE for 1 year)- stainless steel skin: ~

1.5 M - warm structure: ~

1.8 M- warm structure assembly and welding: ~ 0.9 M (10 FTE for 4

months)- transport:

~ 0.6 M- various:

~ 1.0 M

12concrete floor

cavern

warm cryostat

It might be simpler if the aspect ratio changes:For example

H: ~10mW: ~21m

cryogenics + services