Pixel electronics for the ATLAS experiment

The ATLAS experiment at LHC will use 3 barrel layers and 2 x 5 disks of sil icon pixel detectors as the innermost elements of the semiconductor tracker . The basic building blocks are pixel modules with an active area of 16.4 m m x 60.8 mm which include an n(+) on n-type silicon sensor and 16 VLSI fron t-end (FE) chips. Every FE chip contains a low power, high speed charge sen sitive preamplifier, a fast discriminator, and a readout system which opera tes at the 40 MHz rate of LHC. The addresses of hit pixels (as well as a lo w resolution pulse height information) are stored on the FE chips until arr ival of a level 1 trigger signal. Hits are then transferred to a module con troller chip (MCC) which collects the data of all 16 FE chips, builds compl ete events and sends the data through two optical links to the data acquisi tion system. The MCC receives clock and data through an additional optical link and provides timing and configuration information for the FE chips. Tw o additional chips are used to amplify and decode the pin diode signal and to drive the VCSEL laser diodes of the optical links. (C) 2001 Elsevier Sci ence B.V. All rights reserved.