Vacuum / cryo links

Design issues

Jo van den Brand, Martin DoetsNikhef

jo@nikhef.nl martind@nikhef.nl Cascina Feb. 3, 2009

West end

Conceptual designAntonio

West input

Rotated DN1000 standard valve

Options: - small or large link - small link: small or large diameter

West input

New valve position

Valve DN630

Adapter 700 for end stations

West / North end

Mi

Mirror

Mi

2370

Cold surface: length: 2370 mm diameter: 1000 mm

Baffles: diameter: 620 mm 3 needed to cover cold surface temperature influences mirror temperature material: glass?

Side view

Reinforcement ribsL = 3490 mmD = 1208 mm

Cryo link details

Heat bridge/expansion bellows

LN2 vessel support

LN2 (250 l)

superinsulation

BaffleD= 620 mm

PumpoutFlange (100 mm)

3.2 mm/m

Transfer line connections

LN2 inlet duct

34 mm

60 mm

LN2 max level (control ± 10 mm)Bath width: 325 mm

Rapid heatup

Phase separator

2 m above cryo link

Water adsorbtion

• Layer 1 micron– 5 × 1022 H2O– Load 10-4 mbar l/s– Epsilon: 0.1 → 0.2– 2 years

• Note the following– Adsorbtion non uniform– Heat load non uniform

Emissivity of S.St.

Summary

• Preliminary design for short cryo links– Length 2.5 m, diameter 1 m– Capacity about 2 years for 1 micron layer– Reduced heat load

• Lower gas load, less bubbles, less nois• Lower LN2 consumption

– Effect on mirrors– Reduced cost

• Test set-up– Operations

• Closed loop condensor

– Bubbles– Etc.