Collisions among proton bunches occur inside the ATLAS experiment at CERN’s Large Hadron Collider up to 40 million times a second. Only a fraction of the collision events are valuable for research and the ATLAS detector must decide which events to store for analysis.
This decision-making is done courtesy of the sophisticated Trigger and Data Acquisition System (TDAQ) software. A central component of the ATLAS operation, TDAQ is custom software that extracts data in real-time from the experiment, processes it and selects interesting events – all others are discarded. ATLAS has now released this software openly under the Apache 2.0 licence, allowing modification, reuse and citation.
“The full TDAQ software collection, a diverse set of software packages that cover the full scope of data acquisition, represents nearly two decades of work by some 170 ATLAS members,” says Wainer Vandelli from CERN and member of the TDAQ management team. “Altogether, the software has around 1.6 million lines of code: 72% C/C++, 12% Java, 10% Python and 6% others.”
Source: “ATLAS releases open software used to filter LHC collisions”, Mariana Velho & Katarina Anthony, CERN