ATLAS Pixel Detector BCM Signal Cable October 5, 2005 E. Anderssen, LBNL

ATLAS Pixel Detector October 2005 E. Anderssen LBNL Cable Model Circle next to cable is ghosted power cable— 5.5mm diameter All Bends are planar—some length could be saved with spiral bends Somewhat complicated shape, less than 270degrees worth of 25mm radius bends Cable spec says 12mm is limit for ‘multiple turn bends’ Modeled 120-S01 SMA Straight Pin connector Current length, ref surface to ref surface of SMA is 1430mm as routed

ATLAS Pixel Detector October 2005 E. Anderssen LBNL Complicated Joggle Bend at BCM End 11mm straight section before first 25mm bend 12mm bend required to ‘shorten’ radial incursion of SMA Changing other bends to 12mm bends would move connector out radially another 7mm (see next slide for why) Potentially a spiral bend would save similar radial distance and allow larger radii, but too difficult to model effectively 25mm 12mm

ATLAS Pixel Detector October 2005 E. Anderssen LBNL SMA connector wants to extend into box… Added reference SMA connector to box layout—had to guess at dimensions, but used Amphenol for direction on box socket Taking what I thought were reasonable cable bend limits, and routing it to the connector position as best I could from where it must be routed, this is where it ends up As per previous slide, some distance can be taken up with tighter or more complicated bends But likely that only gets you half-there Would be good to move boxes in radially say 10mm to be safe, this seems the best option… 15mm

ATLAS Pixel Detector October 2005 E. Anderssen LBNL Why the complicated curvature bends at BCM Old cable without joggle, intersected Service panels—joggle is needed to bring cable closer to centerline of BCM/Longeron to clear service panels Power Cable, though larger in diameter than the Signal Cable, is closer to center, and likely does not need joggle I have not modelled the power cable yet

ATLAS Pixel Detector October 2005 E. Anderssen LBNL Another Good Reason to move in Radially… The object in Red is the Service Panel structure The Yellow field bounded by the green part is a routing channel for my environmental services While the BCM Box and Mounts do not directly hit anything in my model… –They are a bit too close for my comfort… –The Accuracy we’ve assumed for their mounting is low, so any deviation risks interference Moving them in radially at least 5mm is required, 10mm is conservative, and better for the cable –Direction of move is along axis of BCM Box, root 2 of that radially To be clear—proposing to move box along its axis 10mm in direction closer to beampipe (but at 45 degrees) 1mm

ATLAS Pixel Detector October 2005 E. Anderssen LBNL Just some pictures of the model

ATLAS Pixel Detector October 2005 E. Anderssen LBNL

ATLAS Pixel Detector October 2005 E. Anderssen LBNL

ATLAS Pixel Detector October 2005 E. Anderssen LBNL

ATLAS Pixel Detector October 2005 E. Anderssen LBNL This too could be a spiral bend It is easier for me to rigorously model jogs and offsets as parallel joggles than spiral bends, here the cables only need to get around objects 4mm wide (center-line shift of only 3.5mm). If I didn’t put in the shift, the models would interfere, but real trajectory is likely just a lazy spiral along the green arrow… Power line will be on other side of aluminum inserts, rejoining the signal cable just before penetrating the orange panel (PP1 Cruciform). This will allow each of them to be relieved together and potted through the penetration. I have not designed the penetration, but will shortly, after I model the power cable.