Design and test of the electron Feature EXtractor (eFEX) preproduction module for the ATLAS Phase-I Upgrade

The Electron Feature Extractor (eFEX) is one of the core subsystems for the Phase-I upgrade of the ATLAS Level-1 Calorimeter Trigger. In Run 3, the eFEX will identify isolated e/g and tau candidates with much higher discriminatory power than in Run 2, using finer granularity information from the calorimeters. The eFEX subsystem consists of 24 eFEX modules housed in two ATCA shelves. Each eFEX module has up to 200 optical input/output links and more than 400 on-board electrical fan-out links, all running at 11.2Gbps. Four eFEX pre-production modules have been made and tested. Presented here are hardware and firmware design experience and test results from the eFEX pre-production modules.