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Repository for managing work on various GAPS' Tasks.
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Can TKR layers be rotated by 90deg? #181

Closed rocco8773 closed 1 year ago

rocco8773 commented 1 year ago

Can the TKR rows be rotated by 90degs such that even layers (including layer 0) can be integrated parallel to the OHP and odd layers perpendicular to the OHP. This is requested to make construction of Layers 0 easier and less risky.

rocco8773 commented 1 year ago

I (@rocco8773) think this is doable, but I'll have to review the foam and OHP routing to confirm there is no conflicts.

rocco8773 commented 1 year ago

Answer

Yes, but it requires redesign and modification to existing components. The is predominately due to the fact that the OHP is not symmetric about the central vertical axis of the Tracker and the foam layers were designed with this in mind.

1st Layer of Foam

The first layer of foam (i.e. below Tracker Layer 9) would need to be redesigned. With a 90deg rotation the OHP thru holes no longer lineup with the OHP. In the end this is not a hard modification and can be done before machining the new set of foam.

Image

Even and Odd Foam Layers are Different

In the original setup the foam strips (GAPS-TKR-MEC-301) used under the even Tracker layers is different than the foam strip (GAPS-TKR-MEC-304) under the odd Tracker layers. As a result, if a layer is rotated, then you'd have to use the foam variation that corresponds to the new orientation and not the foam strip that was originally used for the layer. That is, the odd layer foam strips would become the even layer foam strips, and visa versa.

In the image below left is TKR-301 and right is TKR-304. Note the strips look almost identical except for the placement of the pass-throughs for the OHP. This is what makes the two parts unique. It would be difficult to make one universal foam strip due to the asymmetric pattern of the OHPs. The universal foam strip would need OHP pass-thrus up and down both sides of the strip, as well as interface board cutouts on each end.

image

Layer 0 Foam Strips (below layer)

The foam strips below Layer 0 are a special a special split design of TKR-301, with the thin strip GAPS-TKR-MEC-306 stacked on top of GAPS-TKR-MED-305 to make an equivalent strip to TKR-301. When rotating the layer the strips will now need to be based off of TKR-304. Again, this is due to the asymmetry of the OHPs.

In the image below left is TKR-305 and right is TKR-306.

image

Layer 0 DET Modules

As Gabe rightfully pointed out, the cooling collar will need to be relocated the opposite location. This will also require the screw holes in that location to be bored out to make enough room for the cooling collar mounting screw to pass-through.

Foam Above Layer 0

There is a three layer stack of foam above Layer 0: GAPS-TKR-MEC-401 which sits on top of the detector modules, GAPS-TKR-MEC-404 which sits between TKR-401 and the OHP to support the OHP, and GAPS-TKR-MEC-500 which sits between the OHP and TOF panel. While I don't think the later two foam layers will need to be modified to rotate the Tracker layers, TKR-401 definitely needs to be modified to account for purge tube routing.

rocco8773 commented 1 year ago

Answer archived in code base...

docs/questions/Can TKR layers be rotated by 90deg.md