Upgrade Design of TileCal Front-end Readout Electronics and Radiation Hardness Studies

The ATLAS Tile Calorimeter (TileCal) is essential for measuring the energy and direction of hadrons and taus produced in LHC collisions. The TileCal consists of "tiles" of plastic scintillator dispersed in a fine-grained steel matrix . Optical fibers from the tiles are sent to ~10,000 photomultiplier tubes (PMT) and associated readout electronics. The TileCal front-end analog readout electronics process the signals from ~10,000 PMTs. Signals from each PMT are shaped with a 7-pole passive LC shaper and split it to two channels amplified by a pair of clamping amplifiers with a gain ratio of 32. Incorporated with two 40Msps 12-bit ADCs, the readout electronics provide a combined dynamic range of 17-bits. With this dynamic range, the readout system is capable of measuring the energy deposition in the calorimeter cells from ~220MeV to 1.3TeV with the least signal-to-noise ratio of greater than 20. The digitized data from each PMT are transmitted off-detector optically, where the data are further processed with dedicated electronics to provide trigger logic and data for physics studies. The sLHC is planned to increase the design luminosity up to 5x1034/sec/cm2. It will be important to upgrade the front-end electronics to cope with the higher radiation levels and to take advantage of the latest technology improvements since the time of the original design. The front-end electronics are required to withstand ~60Krad over their lifetime. As a R&D project, we are currently using commercially available off-the-shelf integrated circuits with deep-submicron technology to design a prototype analog readout board associated with this upgrade. We will present the test results of electronics performance and radiation hardness studies for the newly designed TileCal front-end readout electronics at the sLHC.