How do we know the present in-line patch panel size (25 x 25 x 2.5 cm**3) will fit in the available space? ECAL Barrel In-line optical patch panel sketch and considerations J. Grahl and W. Funk 23 March 2004 Questions this report addresses: What is the vertical and horizontal path of the fiber from the bottom of the patch panel box to the SM feedthrough? Will that path violate the 3cm (ideally 4cm) bending radius restriction?

Horizontal plate Inside SM 4 cm 14 cm 25 cm MEM box Feedthrough r =4 cm L = 10 cm In-line patch panel box Location of the EB In-line patch panel box and fiber route from there into the SM (not to scale). Measurements taken from design files: 2.5 cm To be determined: what protects and holds fiber in place in this region? crystals electronics fiber, patch panels, etc. Tracker HCAL

Some photos of the TK/EB mock-up in Building 186: Measurement of vertical space between inline patch panel box and MEM box (horizontal plate)…~5cm MEM box (note in the correct EB configuration this would be below the horizontal plate) Inside SM Feedthrough In-line patch panel box

The present in-line patch panel size (25 x 25 x 2.5 cm**3) will fit in the available space. Conclusions: The fiber travels out the bottom of the box, in a 4cm-radius curve, then 10 cm horizontally to enter the SM feedthrough. It is not yet known what will protect and hold the fiber in place in this region.