Test of the first RPC-BIL prototype in view of the Mechanics Final Design Review

In view of the HL-LHC luminosity increase, (7×1034 cm-2s-1 @ 14 TeV p-p, <µ> =200) the Atlas Muon-Trigger needs significant upgrades. The RPC system will be upgraded adding 272 new generation RPC detectors in the Barrel Inner and replacing the old on detector trigger PADs with new DCTs. The upcoming upgrade will bring significant enhancements to the system. It will increase trigger redundancy by expanding from 6 to 9 layers, resulting in heightened reliability. Acceptance will see a remarkable improvement, surging from 78% to 92%, reaching an impressive 96% with BI-BO coincidence. The spectrometer lever arm will be extended from 2.3 meters to 4.5 meters, enhancing measurement accuracy. Additionally, the upgrade will lead to improved tracking and trigger capabilities, while time resolution for TOF measurements will be notably refined.