1. Vacuum / cryo links Mechanical design issues Jo van den Brand, Martin Doets Nikhef jo@nikhef.nljo@nikhef.nl martind@nikhef.nl Cascina, January 21, 2010martind@nikhef.nl

2. West end Conceptual design Antonio (March, 2009)

3. West input Rotated DN1000 standard valve Options: - small or large link: small is baseline - small link: small or large diameter, length

4. West input Short cryo link DN630 standard valve (D = 650 mm) DN1000 standard valve Ion pumps

5. West input Valve DN630 Adapter 700 for end stations

6. West / North end Cold surface: length: 2060 mm diameter: 900 mm Q3: Baffles layout?: diameter: 600 mm ? 3 needed to cover cold surface? temperature influences mirror temperature material: stainless / glass? Mirror Q2: prefer smaller diameter Q4: layout different for input and end links

7. Top view L = 3490 mm D = 1208 mm S.St. 304LReinforcement ribs Hydroformed bellows

8. End view and cross section

9. Side view Space for baffles 1100 Baffles not drawn

10. Side view

11. Design detail: suspensions Movable part Fixed part (to rib / vessel) Rib

12. LN2 tests S.St. 304L vessel 50 x 50 x 5 cm 3 Isolated by 20 cm foam Average heat leak 50 W/m2 (similar to radiation load on surface with emissivity of 0.1) Evaporate ~1 l/hour Measured acoustic noise (~60 dB, 0.02 Pa)

13. Performance Expected water load: 10 -4 mbar l/s – Q 1 year = 3150 mbar l gas – 22,400 mbar l = 1 mol = 18 gram – Thus, expected load 0.14 mol or 2.5 gram water Expected layer – Length 2.0 m, diameter 1 m, Area =  DL – Number of sites 10 15 cm -2 – After 1 year expect 0.4 micron layer Heat load and LN2 consumption – Depends on emissivity 0.1 – 0.2 – Heat load 200 – 300 W LN2 consumption: 3.5 liter/hour Expected gas load: 0.2 liter/s

14. Logistics Quotations: total 789 kEuro (939 kEuro including VAT) – R&D phase10 kEuro – Design & engineering45 kEuro – Short link 125 kEuro x 4 Standard phase separator Simple LN2 extraction Simplification of separation rings for LN2 circuit – Valve DN63039.8 kEuro x 4 ex VAT ex 7.5% discount – Other items75 kEuro Valve DN100 Turbo molecular pump station Gauges, control, tubing, etc. Manpower ~ 5 fte – Mechanical and control system design – Construction of (support) structures, etc – Testing – Installation

15. Summary Preliminary design for short cryo links – Length 2.0 m, diameter 0.9 m – Capacity > 1 year for 1 micron layer – Reduced heat load: 200 – 300 W LN2 consumption: 3.5 liter/hour Low gas load (0.2 liter/s), less bubbles, less noise – Thermal effect on mirrors acceptable – Reduced cost Test set-up – Operations External vs closed loop condensor Consumption versus coverage (emissivity development) Control issues (normal running, regeneration, …) – Bubble induced noise

16. Next Steps Optical interfaces are being defined = trap length and diameter. Towers position in May/June, the explicit approval on diameter is expected in shorter time Trap design is being optimized vs bubbling noise The order of the first trap (prototype) shall be shifted in the second half of 2010, without affecting the milestone ‘completion’ of Nov2012.