Electronics for the CMS muon drift tube chambers: the read-out minicrate

On the CMS experiment for LHC collider at CERN, the drift tube chambers (DT´s) are responsible of muon detection and precise momentum measurement. Described in this paper is the first level of the read out electronics for these DT chambers that will be located inside the muon barrel detector in the so-called minicrates (MC), attached to the chambers. The read out boards (ROB) are the main component of this first level data acquisition system, and they are in charge of the time digitalization related to level 1 accept trigger of the incoming signals from the front-end electronics, following a consequent data merging to next stages of the data acquisition chain. Its architecture and functionality has been exhaustively tested, as well as its capability of operation beyond the expected environmental and radiation conditions inside the CMS detector. The satisfactory results obtained have allowed to proceed with ROB final production and its assembly in the MCs. A total amount of 250 MCs and around 1500 ROBs are being produced and tested thoroughly at CIEMAT (Spain), including burn-in tests for guaranteeing ten years of limited maintenance operation. An overview of the system and a summary of the different results of the tests performed on ROB´s and MC will be presented. They include acceptance tests for the production chain as well as some validation tests that insured proper operation of the ROB´s beyond the CMS detector conditions.