The NA62 Gigatracker Detector properties and pixel read-out architectures

The beam spectrometer of the NA62 experiment named Gigatracker has to perform single track reconstruction with unprecedented time resolution (150 ps rms) in a harsh radiation environment To meet these requirements and in order to reduce material budget to a minimum three hybrid silicon pixel detector stations will be Installed in vacuum An adequate strategy to compensate for the discriminator time-walk must be implemented and R&D investigating two different options is ongoing Two read-out chip prototypes have been designed in order to compare their performance one approach is based on the use of a constant-fraction discriminator followed by an on-pixel TDC while the other one is based on the use of a time-over-threshold circuit followed by a TDC shared by a group of pixels This paper describes the Gigatracker system presents the global architectures of both read-out ASICs and reviews the current status of the R&D project (C) 2010 Elsevier B V All rights reserved