FELIX: the New Detector Interface for the ATLAS Experiment

TL;DR

FELIX is a new detector interface system for ATLAS at the LHC, using commodity hardware and FPGA technology to improve data routing, processing, and integration with trigger systems during the 2019-2020 upgrade.

Contribution

The paper introduces FELIX, a novel FPGA-based, commodity hardware system that enhances data acquisition and processing for ATLAS's detector upgrade.

Findings

FELIX successfully integrated with ATLAS front-ends.

Early performance tests show high data throughput.

FELIX improves data routing and trigger integration.

Abstract

During the next major shutdown (2019-2020), the ATLAS experiment at the LHC will adopt the Front-End Link eXchange (FELIX) system as the interface between the data acquisition, detector control and TTC (Timing, Trigger and Control) systems and new or updated trigger and detector front-end electronics. FELIX will function as a router between custom serial links from front-end ASICs and FPGAs to data collection and processing components via a commodity switched network. Links may aggregate many slower links or be a single high bandwidth link. FELIX will also forward the LHC bunch-crossing clock, fixed latency trigger accepts and resets received from the TTC system to front-end electronics. The FELIX system uses commodity server technology in combination with FPGA-based PCIe I/O cards. The FELIX servers will run a software routing platform serving data to network clients. Commodity servers connected to FELIX systems via the same network will run the new Software Readout Driver (SW ROD) infrastructure for event fragment building and buffering, with support for detector or trigger specific data processing, and will serve the data upon request to the ATLAS High Level Trigger for Event Building and Selection. This paper will cover the design and status of FELIX, the SW ROD, results of early performance testing and integration tests with several ATLAS front-ends.