The Serial Link Processor for the Fast TracKer (FTK) processor at ATLAS

The Associative Memory (AM) system of the Fast Tracker (FTK) processor has been designed to perform pattern matching using the hit information of the ATLAS experiment silicon tracker. The AM is the heart of FTK and is mainly based on the use of ASICs (AM chips) designed to execute pattern matching with a high degree of parallelism. The AM system finds track candidates at low resolution that are seeds for a full resolution track fitting. To solve the very challenging data traffic problems inside FTK, multiple board and chip designs have been performed. The currently proposed solution is named the “Serial Link Processor” and is based on an extremely powerful network of 828 2 Gbit/s serial links for a total in/out bandwidth of 56 Gb/s. This paper reports on the design of the Serial Link Processor consisting of two types of boards, the Local Associative Memory Board (LAMB), a mezzanine where the AM chips are mounted, and the Associative Memory Board (AMB), a 9U VME board which holds and exercises four LAMBs. We report on the performance of the hardware and firmware intermediate prototypes produced for the global FTK integration, an important milestone to be reached before the FTK production.