Design of the front-end analog electronics for the ATLAS tile calorimeter

We describe the design of the analog portion of an electronics system to process signals from the photomultiplier tubes of the ATLAS Tile Calorimeter. The system has a 16-bit dynamic range and is capable of measuring energy depositions in a single calorimeter cell from ∼20MeV to ∼1.3TeV. In order to maintain the calorimeter calibration at the 1% level the system includes a charge injection circuit and a current integrator for use with a cesium source system and with the time-averaged currents produced by the LHC. The system also provides a signal for an analog adder which produces an energy sum for each calorimeter tower. Over 10,000 channels of this system have been constructed and delivered for use.