Engineering Papers⌕ Search
Home/Archive/DOE OSTI

DOE OSTI · 3027536

The high level trigger and express data production at STAR

Betts, Wayne [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0009000378394484)·Chen, Jinhui [Fudan University, Shanghai (China)] (ORCID:000000017032771X)·Fisyak, Yuri [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000231518377)·Ke, Hongwei [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000314637291)·Kisel, Ivan [Goethe University, Frankfurt (Germany); Frankfurt Institute for Advanced Studies (FIAS) (Germany); Helmholtz Research Academy Hesse (HFHF), Frankfurt (Germany); GSI-Helmholtz Centre for Heavy Ion Research, Darmstadt (Germany)]·Kisel, Pavel [Goethe University, Frankfurt (Germany)]·Kozlov, Grigory [Goethe University, Frankfurt (Germany)]·Landgraf, Jeffery [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0009000341389753)·Lauret, Jerome [Brookhaven National Laboratory (BNL), Upton, NY (United States)]·Ljubicic, Tonko [Rice University, Houston, TX (United States)]·Ma, Yugang [Fudan University, Shanghai (China); East China Normal University (ECNU), Shanghai (China)]·Margetis, Spyridon [Kent State University, Kent, OH (United States)]·Qiu, Hao [Chinese Academy of Sciences (CAS), Lanzhou (China)]·Shen, Diyu [Chinese Academy of Sciences (CAS), Lanzhou (China)] (ORCID:0000000324345540)·Shou, Qiye [Fudan University, Shanghai (China)]·Sun, Xiangming [Central China Normal University, Wuhan (China)]·Tang, Aihong [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000219972104)·Van Buren, Gene [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000182103860)·Vassiliev, Iouri [GSI-Helmholtz Centre for Heavy Ion Research, Darmstadt (Germany)] (ORCID:0000000202256638)·Xi, Baoshan [Fudan University, Shanghai (China)]·Ye, Zhenyu [University of Illinois, Chicago, IL (United States)] (ORCID:0000000160916772)·Zhang, Zhengqiao [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0009000742521735)·Zyzak, Maksym [Frankfurt Institute for Advanced Studies (FIAS) (Germany)]
View original source ↗Read source document ↗Export metadata ↓

Abstract

To meet the demands of the Beam Energy Scan phase-II (BES-II) program, the STAR experiment at the Relativistic Heavy Ion Collider (RHIC) developed a dual real-time framework consisting of a High Level Trigger (HLT) and an Express Data Production system (xProduction). The HLT operates online within the Data Acquisition (DAQ) chain on a dedicated multi-core CPU cluster with the option to offload compute-intensive kernels to Xeon Phi coprocessors. It uses parallelized algorithms, such as the Cellular Automaton (CA) Track Finder, to perform rapid tracking, vertexing, and event filtering. This allows it to select events of interest in real time and provide immediate feedback on detector and beam conditions. In contrast, the xProduction workflow runs concurrently and independently of the DAQ loop. It applies near offline-quality calibration and reconstruction within hours of data collection. The xProduction input is the express data stream, whose content can be enriched by HLT trigger/priority selections under DAQ/HLT resource constraints, and it uses the STAR calibration/conditions framework, incorporating online calibration/QA information when available. This enables early preliminary physics analysis, including the reconstruction of rare signals, such as hyperons and hypernuclei. It also provides collaboration-wide access to analysis-ready datasets. Together, the HLT and xProduction systems form a complementary architecture: the HLT performs online event selection while the xProduction chain delivers high-quality results within a short amount of time. This integrated framework has enabled the prompt reconstruction of the $^5_Λ$ He hypernucleus with high statistical significance and the efficient processing of hundreds of millions of heavy-ion collision events. In conclusion, its demonstrated scalability and robustness establish a model for future high-luminosity experiments requiring both online event filtering and rapid access to analysis-quality data.

Explore related subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICSDAQData AcquisitionExpress Data ProductionHeavy ion collisionHigh Level TriggerKFParticleOnline event selectionOnline trackingRHICSTAR

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Betts, Wayne [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0009000378394484), Chen, Jinhui [Fudan University, Shanghai (China)] (ORCID:000000017032771X), Fisyak, Yuri [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000231518377), Ke, Hongwei [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000314637291), Kisel, Ivan [Goethe University, Frankfurt (Germany); Frankfurt Institute for Advanced Studies (FIAS) (Germany); Helmholtz Research Academy Hesse (HFHF), Frankfurt (Germany); GSI-Helmholtz Centre for Heavy Ion Research, Darmstadt (Germany)], Kisel, Pavel [Goethe University, Frankfurt (Germany)], Kozlov, Grigory [Goethe University, Frankfurt (Germany)], Landgraf, Jeffery [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0009000341389753), Lauret, Jerome [Brookhaven National Laboratory (BNL), Upton, NY (United States)], Ljubicic, Tonko [Rice University, Houston, TX (United States)], Ma, Yugang [Fudan University, Shanghai (China); East China Normal University (ECNU), Shanghai (China)], Margetis, Spyridon [Kent State University, Kent, OH (United States)], Qiu, Hao [Chinese Academy of Sciences (CAS), Lanzhou (China)], Shen, Diyu [Chinese Academy of Sciences (CAS), Lanzhou (China)] (ORCID:0000000324345540), Shou, Qiye [Fudan University, Shanghai (China)], Sun, Xiangming [Central China Normal University, Wuhan (China)], Tang, Aihong [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000219972104), Van Buren, Gene [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000182103860), Vassiliev, Iouri [GSI-Helmholtz Centre for Heavy Ion Research, Darmstadt (Germany)] (ORCID:0000000202256638), Xi, Baoshan [Fudan University, Shanghai (China)], Ye, Zhenyu [University of Illinois, Chicago, IL (United States)] (ORCID:0000000160916772), Zhang, Zhengqiao [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0009000742521735), Zyzak, Maksym [Frankfurt Institute for Advanced Studies (FIAS) (Germany)]. 2026-03-18. The high level trigger and express data production at STAR. https://doi.org/10.1016/j.nima.2026.171489

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related reports

DOE OSTI2026

Design-informed neutronics assessment of long-lived fission product transmutation in a tokamak fusion reactor blanket

This study presents a neutronics-based assessment of the feasibility and viability of transmuting six major long-lived fission products (LLFPs) from light-water reactors, namely 99 Tc, 129 I, 79 Se, 93 Zr, 126 Sn, and 135 Cs, within the blanket region of a tokamak fusion reactor, using the MIT ARC design as a concrete fusion configuration. Monte Carlo neutronics simulations were performed to evaluate LLFP transmutation and to compare the results with a reference boiling water reactor (BWR). The results indicate that transmutation of all six LLFPs is neutronics-feasible in fusion reactors, with transmutation half-lives significantly shorter than their natural decay half-lives. For elemental targets, transmutation of 135 Cs, 126 Sn, and 93 Zr was found potentially viable, as the net mass transmuted exceeded that achievable in the reference BWR under identical target volume and irradiation time. When isotopically separated targets were considered, transmutation of 126 Sn and 93 Zr appeared potentially viable. A parametric study demonstrated that plasma geometry modifications can enhance local neutron flux, increasing the transmuted 93 Zr mass by approximately 33% and reducing the transmutation half-life from approximately 240 years to 180 years. Repositioning the target and adjusting material layer thickness reduced the transmutation half-life of 93 Zr to 67 years and increased the net mass transmuted by a factor of 50. Furthermore, these results demonstrate that fusion reactors can enable LLFP transmutation beyond the practical limits of thermal fission reactors and highlight the critical role of reactor and blanket design optimization. Engineering and fuel-cycle considerations required for deployment are beyond the scope of this neutronics-focused study.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2026

A hybrid Monte Carlo-deterministic second moment method with efficient variance reduction

In this work, we present a hybrid method that combines Monte Carlo with deterministic finite element methods to solve a linear Boltzmann transport equation. Our hybrid method runs orders of magnitude faster than Monte Carlo, without sacrificing accuracy, for a proxy problem from radiative transfer that contains both optically-thick and optically-thin material. We believe that this is the first demonstration of a hybrid Second Moment Method in more than one spatial dimension, the first to consider more than one material, and the first to use variance reduction. Our variance reduction approach arises from an asymptotic analysis in which we show that the magnitude of the scattering source grows without bound. We transform the problem to compute the deviation of the radiation intensity from isotropy. The magnitude of the source in the transformed problem is bounded, and the quality of the hybrid method solution is dramatically improved by a substantial reduction in the variance.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗