readout plate

Readout plate

Based on this sketch Snapshots from this EASM file
Fibers go from the end of the 1m bars to a small insert in a readout plane (colored green, nominally 1/4" Al). The vertical offset of the fibers is 3", lifting the preamps away from the hot midplane, and clearing a space below the plate for cable bundles to exit. The preamp boards sit on this side of the plate, as shown, mounted at a small angle so that ribbons and coaxes don't get ito each others' way. Readout plate for the 80-bar units.
The other side of the plate is shown here. SiPMs sit in square wells, held inn place by a thin cover plate (yellow) [we did this rather than epoxy the SiPMs in place]. Twisted pairs go to the preamp boards, exposed through a hole. I think for now, the holes on both the SiPM end and the preamp board end should be big enough for a 2-pin 1/10" connector. We can decide later if we solder both ends of the twisted wire pair, or have 1 or 2 connectors.
A 4" flange on the top surface is the cooling air inlet. We can have flanges on the bottom, and something like this on the back face where the cables come out.
Mockup of one end of the '80 bars' plate, with a number of the readout boards in place. The ribbons can be led low and along the side, and the coaxes rise higher. Here, a few straight-connector coaxes are put in place, but a better option is to use right-angle connectors. In the mockup, a bundle of 6 ribbons and one of 7 ribbons are shown going to the right. In the full-scale 80-bar units, these would be bundles of 10, 4 going to the right, and 4 going to the left.
In order to protect the back of the amplifier boards from shorting on the aluminum mounting plate, I cut some protective masks out of mylar (old overhead slides, 150 μm thick). Converted to pdf, eps, svg at VectorMagic.com, and traced in Inkscape: svg, pdf. I laser-cut the pdf on a Zing laser cutter (import into Adobe Illustrator, print, speed 60, power 15) Mask for the 2cm bars: png, pdf. Easier path: import png to Inkscape, trace in a new layer (with linewidth 0.1px for cutting), save as svg file. This can be used directly on the cutter. mask_1m.svg, mask_80_inkscape.svg, mask_80cm.svg
Fiber input side of the 80-bar unit.
Back side
On the 2cm-bar plate, the 80/20 posts partially (but barely, as indicated by the red lines) cover the openings for the preamps. This should not interfere with the red wires coming out.
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Hubert van Hecke

Last modified: Fri Mar 24 12:16:21 MDT 2017