1. End-of-stave region

2. 2 Space Z-dimension is critical –Keep gap small (might help getting rid of stubs) Edge of last barrel silicon (at corner) is 1277 Edge of stave is given by number of traces which need to get routed around last module –Probably requires one HV per stave side Then interlinks and service gap (incl. space for bends and tooling) Then insertion clearance (here 20mm) Then envelope of first disk –Driven by EOP card (optoconverter) Need to optimize all of these This needs to be 1415 Lacking 45mm Current best estimates:

3. 3 Services Goal is to prevent external loads on stave –During installation –During operation (mostly thermal) –Support from interlink or endflange Electrical (LV, HV, DCS): –1 connector per side –Preferred solution: flex-rigid (trace layer from EOS card extended flexibly, ending on another PCB for connector) –Connector PCB supported by interlink or endflange Cooling pipes –Fully clamped from interlink or endflange –But not overconstraining stave position… Optical –1 Optoconverter per side –Fibres (single fibres in furcation tubing) will drive how far back optos will sit.

4. 4 Cooling pipe add-ons Ground connection close to EOS –Clamp, connected to EOS with braid? –Could maybe be included into clamping to interlink/endflange Electrical break –Having it close to stave would make management of type I pipes easier –Also could help insulating stave electronics for orbital welding –Placing break before clamp would nicely protect it mechanically But it would require more z-space, and Requires separate ground connection clamp Transition to larger (smaller) diameter and wall? –This could simplify final stave connection –Could be part of the insulating break design DCS interlock sensors –Would like to avoid separate clamps (like in barrel SCT) –Either place it as SMD on end of tape Compact, no dangling wires, just trace to EOS, but requires z-space –Or integrate into mechanical clamping to interlink/endflange

5. 5 Interlinks I prefer continuous interlinks –I don’t think we will find 2 slices per quadrant where we can bring out the interlink without being on top of services – that means that interliks would take additional z-space –I suspect continuous interlinks give higher torsional stiffness between cylinders (weak modes) If we do continuous, when do we mount interlink? –Before insertion: Have good access, but insertion tooling needs to provide space –After insertion