Speaker
Description
The Spin Physics Detector (SPD) is currently under construction at the second interaction point of the NICA collider at JINR. Its primary physics goal is to test fundamental aspects of Quantum Chromodynamics by studying the polarized structure of the nucleon and investigating spin-dependent phenomena in collisions of longitudinally and transversely polarized protons and deuterons. These collisions will reach a center-of-mass energy of up to 27 GeV and a luminosity of up to 10^32 cm^−2 s^−1.
Due to the use of a free-running data acquisition (DAQ) system, the experiment facility will produce a continuous data stream at an estimated rate up to 20 GB/s (approximately 200 PB/year). Unlike conventional setups, hardware-level event selection is not feasible for SPD, as trigger decisions depend on reconstructed tracking information—such as momentum and vertex position—which cannot be determined at the earliest stage of data taking. Consequently, the raw data stream requires real-time processing to unscramble and assemble individual physics events.
To meet requirements for primary data processing, a dedicated computing system—the SPD Online Filter—is being developed. This facility will perform data processing on the full data throughput from the DAQ system, executing multistep workflows as for real-time event selection so for other needs like data quality monitoring, partial calibration etc. This presentation will describe the conceptual design, system architecture, and current implementation status of the SPD Online Filter.