The ATLAS RPC-BIS78 Readout and Trigger System.

In this paper we describe the BIS78-RPC detector, mainly focusing on the Readout and Trigger electronics system. The aim of the BIS78 project is to provide new integrated sMDT+RPC chambers for the Phase-I upgrade of the Muon Spectrometer of the ATLAS Experiment at the LHC at CERN. The BIS78-RPC chambers are also a pilot deployment of RPC chambers to be used in the full barrel inner layer for Phase-II upgrade. The on-chamber front-ends include an amplifier, a discriminator ASIC and an LVDS transmitter. This signal is digitized by CERN HPTDC chips and then processed by an FPGA which is the heart of the readout and trigger processing. The on-detector electronics and trigger system, and in particular the firmware, is described in this paper, including the related validation test results.