Modules, Cables and Eta=0 (1)

Murrough Landon - 12 November 1999

Eta=0 and Other Issues

• Is Eta=0 still an unresolved issue?
• TDR concept has one PPM spanning eta=0
• RX/PPM organisation assumes no PPM spans eta=0
• FCAL and outer EMEC/HEC PPMs span more than one quadrant
• Connector granularity on PPMs?

Implications if no PPM spans eta=0

• If CPMs and JPMs do still span eta=0, the PPM connectors must allow one PPM to feed two CPM/JEMs (ie 2*16 towers).
• Do cable bundles of 2*16 pose layout problems for the CPM/JEMs? Are 4*N bundles preferred?
• If CPMs do not span eta=0, we need 14 CPMs per crate (instead of 13). Affordable from LVDS and FPGA savings?
• If JEMs do not span eta=0, the FCAL channels will (presumably?) appear as the outer channels of the two outer JEMs (instead of only in a single separate 16th JEM).
• FCAL trigger setup more complicated if FCAL is not in separate JEM?