CMOS front-end for the MDT sub-detector in the ATLAS Muon Spectrometer, development and performance

Development and performance of the final 8-channel front-end for the MDT segment of the ATLAS Muon Spectrometer is presented. This last iteration of the readout ASIC contains all the required functionality and meets the design specifications. In addition to the basic "amplifier-shaper-discriminator"-architecture, MDT-ASD employs a Wilkinson ADC within each channel for precision charge measurements on the leading fraction of the muon signal. The data will be used for discriminator time-walk correction, thus enhancing the spatial resolution of the tracker, and for chamber performance monitoring (gas gain, ageing etc.). It was also demonstrated that this data can be used for performing particle identification via dE/dX. A programmable pulse injection system which allows for automated detector calibration runs was implemented on the chip. Results of performance and functionality tests on prototype ASICs, both in the lab and on-chamber, are presented.