Muon Trigger Upgrade Research Articles

Status of the MDT Trigger Processor for the ATLAS Level-0 Muon trigger at the HL-LHC

The MDT Trigger Processor (MDTTP) is a key ATLAS Level-0 Muon trigger upgrade component designed to meet High-Luminosity LHC requirements. The MDTTP will use MDT hits in the hardware level trigger for the first time in ATLAS to improve the momentum resolution of muon candidates provided by RPC and TGC detectors and reduce the fake muon trigger rate.The MDTTP hardware is based on the Apollo ATCA platform. The prototype includes a VU13P-FPGA, high-speed FireFly optical transceivers, peripherals, and other improvements learned from using the previous hardware demonstrator. We present the prototype status, firmware implementation, core algorithm, slow-control software, and first integration tests.

Development of FPGA-based neural network regression models for the ATLAS Phase-II barrel muon trigger upgrade

Effective selection of muon candidates is the cornerstone of the LHC physics programme. The ATLAS experiment uses a two-level trigger system for real-time selection of interesting collision events. The first-level hardware trigger system uses the Resistive Plate Chamber detector (RPC) for selecting muon candidates in the central (barrel) region of the detector. With the planned upgrades, the entirely new FPGA-based muon trigger system will be installed in 2025-2026. In this paper, neural network regression models are studied for potential applications in the new RPC trigger system. A simple simulation model of the current detector is developed for training and testing neural network regression models. Effects from additional cluster hits and noise hits are evaluated. Efficiency of selecting muon candidates is estimated as a function of the transverse muon momentum. Several models are evaluated and their performance is compared to that of the current detector, showing promising potential to improve on current algorithms for the ATLAS Phase-II barrel muon trigger upgrade.

The CMS Barrel Muon trigger upgrade

The increase of luminosity expected by LHC during Phase1 will impose tighter constraints for rate reduction in order to maintain high efficiency in the CMS Level1 trigger system. The TwinMux system is the early layer of the muon barrel region that concentrates the information from different subdetectors: Drift Tubes, Resistive Plate Chambers and Outer Hadron Calorimeter. It arranges the slow optical trigger links from the detector chambers into faster links (10 Gbps) that are sent in multiple copies to the track finders. Results from collision runs, that confirm the satisfactory operation of the trigger system up to the output of the barrel track finder, will be shown.

A muon trigger upgrade with high transverse momentum resolution for the ATLAS detector at the High-Luminosity LHC

The Level-1 trigger for muons of the ATLAS experiment is based on trigger chambers with excellent timing resolution which identify muons coming from a particular beam crossing. To cope with the stringent constraint on the trigger rates expected during phase II of the LHC, the so-called High-Luminosity LHC, it is proposed to include precision tracking chambers in the Level-1 muon trigger for improving the transverse momentum resolution. The rate of a single muon trigger with a transverse momentum threshold of 20 GeV is estimated to be reduced by about a factor of two over the entire pseudorapidity region by introducing the proposed upgrade. An architecture of the electronics includes an additional priority readout chain, which is independent of the standard and asynchronous readout. A demonstrator of the frontend electronics has been developed and an initial test based on cosmic muons shows position resolution measurements consistent with the simulation.

Muon trigger upgrade at PHENIX

The Relativistic Heavy Ion Collider (RHIC) at BNL provides a unique opportunity to collide polarized protons. One of the hightlight of the spin program at = 500 GeV is the direct measurement of sea quark contribution to the proton spin via W-boson production by measuring parity violating single spin asymmetry. A new trigger on forward muons in PHENIX identifies and triggers on high momentum Ws suppressing a large number of low momentum muons coming from hadronic decays. Since the current muon trigger will fire on any muon above 2 GeV/c, it will not provide the required rejection factor for 500 GeV running, which is about 7500. Two major upgrade projects are parts of this Muon Trigger; 1) Resistive Plate Chambers, 2) the muon tracker front end electronics upgrades. The status of these upgrade projects is discussed in this document as well as physics goal of W program at RHIC.

PHENIX RPC R&D for the fast RPC muon trigger upgrade

The PHENIX collaboration at relativistic heavy ion collider (RHIC) will measure the maximal parity violating W asymmetries in polarized proton–proton collisions at high transverse momentum in order to make the most precise measurement of the quark and the anti-quark polarizations of the proton. For this measurement, the collaboration is installing resistive plate chambers (RPCs) similar to the CMS Endcap RPCs in the two existing muon spectrometers. In these proceedings, we shall discuss the research and development (R&D) that has been done by the collaboration in order to both understand and develop RPC technology. The R&D has been carried out at Georgia State University, the University of Colorado at Boulder, and the University of Illinois at Urbana-Champaign with many other institutions contributing as well; each university has focused on the different aspects of the RPCs. Georgia State has focused on detector design, performance, and stability; Colorado has tested the front end electronics and termination schemes; Illinois has performed position resolution studies as well as two-dimensional efficiency scans of RPCs. Additionally, a cosmic ray teststand for final gap QA is currently operational at Brookhaven National Laboratory (BNL).

Assembly, testing, and installation of the fast RPC muon trigger upgrade for PHENIX

Many important questions remain to be answered about the origin of the proton spin. A new fast resistive plate chamber (RPC) based trigger system is being developed for the PHENIX muon spectrometer arms that will allow, for the first time, the measurement of the flavor structure of the quark polarization in the proton through the observations of W-bosons in polarized proton–proton collisions at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). The new PHENIX muon trigger will improve the efficiency by which the data acquisition system can identify potential W events by approximately two orders of magnitude. W-bosons can be detected through the appearance of a high-energy muon in one of the two existing muon spectrometers. The trigger upgrade is based on new front-end electronics for the muon tracking chambers and RPCs that will be installed in three stations of both muon arms starting with prototype chambers in 2008. Components of the RPCs are being fabricated at many different locations around the world. After they are shipped to BNL, these components will be tested and then the RPC modules will be assembled at a newly completed facility. Once assembled, these modules will be extensively tested and joined in half octant units for installation into the PHENIX spectrometer. Prototype chambers have been assembled and tested.