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SPL RF coupler: integration aspects. V.Parma, TE-MSC with contributions from WG3 members: Th.Renaglia, U.Wagner, P.Coelho, N.Bourcey, A.Vandecraen . Review of SPL coupler, CERN 16th-17th March 2010. β =1 cryo -module in SPL layout ( drwg SPLLJL__0014).
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SPL RF coupler: integration aspects V.Parma, TE-MSC with contributions from WG3 members: Th.Renaglia, U.Wagner, P.Coelho, N.Bourcey, A.Vandecraen Review of SPL coupler, CERN 16th-17th March 2010
Cavity/coupler assy Part of interest Double-walled-tube
Possible supporting schemes “standard” supporting scheme RF coupler Invar longitudinal positioner Inertia beam Fixed support Sliding support External supports (jacks)
Possible supporting schemes “standard” supporting scheme RF coupler Invar longitudinal positioner Inertia beam Fixed support Sliding support External supports (jacks)
Possible supporting schemes Coupler supporting scheme RF coupler + longitudinal positioner + vertical support Intercavity support structure External supports (jacks)
Coupler position: top ...? • Contras: • Interferes with bi-phase tube move sideways • Waveguides/coupler more exposed to personnel/handling (damage, breaking window?) • Pros: • Easier connection of waveguides • Easier access (needed?)
Coupler position: ...or bottom? • Contras: • Space needs for waveguides under cryostat • If coupler not a support (bellows) support on top, i.e. centered tube not possible • Pros: • Centered bi-phase tube symmetry • Waveguides/coupler protected
RF coupler assembly constraints • Defines minimum diameter of “pipeline” type vessel: • Lenght of double-walled tube • Integration of thermal shield Note: drwgs for information only (concept not final)
Need guiding? Layout Equivalent sketch No - If sag small enough - If strenght OK - isostatic l Yes - couple cavities - hyperstatic inter-cavity guides 2l mid cavities most critical: sag reduces only to ½
Max sag: “to guide or not to guide?” Stiffening of coupler/cavity assembly necessary Guiding between cavities is most probably necessary
“standard” supporting Max. sag minimized at a/L=0.20. A 3rd central support seems mandatory
comparing solutions A) Coupler supporting scheme B) “standard” supporting scheme
Summary • Coupler length (double-walled tube) sets minimum diameter of cryo-module • Coupler could be used as cavity support and is an interesting option • Vacuum vessel become of paramount importance for mechanical positioning/stability • Guiding between cavities probably needed (relieve cantilever) • In case of “standard” supporting solutions, coupler design considerations still valid mechanical decoupling with bellows