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Mechanical design of the Roman pots. Status report M.Oriunno In Collaboration with L.Favre, G.Laurent and R.Perret EST Division F. Haug AT Division. SSTEEL 316. Inconel 600. Welding on a flat foil and folding. Inconel 718. What must be done on the pot design:
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Mechanical design of the Roman pots Status report M.Oriunno In Collaboration with L.Favre, G.Laurent and R.Perret EST Division F. Haug AT Division
SSTEEL 316 Inconel 600 Welding on a flat foil and folding Inconel 718
What must be done on the pot design: • Production of 5 pot prototypes to test under vacuum the welding technology of the thin window (June 2003) • Test on welding technology….Inconel loose ~30% of mech. strength • Electrochemical machining without welds. • Pot Prototype for RF Pick up test on electronics • Calculations • No problems found on other beams (Desy)…check the bunch structure
Compensation bellow Lever Arm Pot Capacitive sensor
Collimator QLR BPM TAN Racks
Cryogenic Cooling (F.Haug, AT/ECR) Heat loads ~12 watt (with vacuum ~10-4 torr) • Two main options: local cooling (microchanneling) or passive elements • Micropumps systems have low reliability, problems on manifolds. • Passive system are preferable: Heatpipes, Peltier Cells • Cold source at 80oK -> pulse-tube (no vibrations) • Other systems as J-T are under investigation < 230oK 2 Watt fews mWatt DT ~ 5oK Heatpipe ~ 1500mm DT ~ 20oK 130oK 80oK Pulse tube
Constraints from the LHC-Vacuum group : • The compensation of the forces must not be relied on a pick up of the primary vacuum • Since all the vacuum chamber in the LSS are NEG coated, the pot must be designed to stand a baked out up to 300oC • A risk analysis of the operation of the detector operation should be performed • A design pressure of at least 1.5 bar shall be considered in the design of the window
Roman Pots’ Chapter in the TDR • Pot Design : Integration study, Simulation and Prototype test results • Cooling System: Capillaries or Cold finger • Roman Pots Station design: precision, stability, vacuum and accessibility • Integration in the Tunnel: Space allocation, services and radiation environment We are ready to write an exhaustive chapter !!
What must be done on the pot design: • Production of 5 pot prototypes to test under vacuum the welding technology of the thin window (June 2003) • Pot Prototype for RF Pick up test on electronics • Production of a mock-up of the pot with dummy detectors to have a full integration exercise with the services (June 2003) Open issues: • Cryogenic Cooling System: Capillary local cooling, Cold fingers. Very unlikely we can spill cryogens from the machine or CMS. LHC/ECR group is working on that. • Electronic RF pickup shielding: are there special constraints on the window ? • Do we have to bake out the pot at 200oC ? • Yes -> a thin window can not stand the thermal stress • No -> a locally increased dynamic pressure of residual gases must be accepted
What has been done for the Roman pot system: • Two solutions have been designed: Symmetric distribution of the loads but less favorable access for maintenance Not symmetric loads but optimized access For Both solutions • A compensation system linked to the primary vacuum allows for a fine regulation but an independent vacuum system can be still implemented • A capacitive system accounting the relative position of the top-bottom pots, • Integration of two Roman Pot stations between the TAN and D2