The CMS Level-1 upgraded calorimeter trigger requires a powerful, flexible and compact processing card. The Calorimeter Trigger Processor Card (CTP7) uses the Virtex-7 FPGA as its primary data ...processor and is the first FPGA based processing card in CMS to employ the ZYNQ System-on-Chip (SoC) running embedded Linux to provide TCP/IP communication and board support functions. The CTP7 was built from the ground up to support AXI infrastructure to provide flexible and modular designs with minimal time from project conception to final implementation.
Test results are presented for two AMC cards, the "CTP6" and "MP7". The two cards take different approaches to connectivity: the CTP-6 has fully-populated backplane connectivity and a 396 Gbps ...asymmetric, optical interface, whilst the MP7 instead favours a 1.4 Tbps, symmetric, all-optical interface. The challenges of designing the MP7 card necessitated the development of several test cards; the results of which are presented.
When the LHC resumes operation in 2015, the higher centre-of-mass energy and high-luminosity conditions will require significantly more sophisticated algorithms to select interesting physics events ...within the readout bandwidth limitations. The planned upgrade to the CMS calorimeter trigger will achieve this goal by implementing a flexible system based on the mu TCA standard, with modules based on Xilinx Virtex-7 FPGAs and up to 144 optical links running at speeds of 10 Gbps. The upgrade will improve the energy and position resolution of physics objects, enable much improved isolation criteria to be applied to electron and tau objects and facilitate pile-up subtraction to mitigate the effect of the increased number of interactions occurring in each bunch crossing. The design of the upgraded system is summarised with particular emphasis placed on the results of prototype testing and the experience gained which is of general application to the design of such systems.
As the LHC increases luminosity and energy, it will become increasingly difficult to select interesting physics events and remain within the readout bandwidth limitations. An upgrade to the CMS ...Calorimeter Trigger implementing more complex algorithms is proposed. It utilizes AMC cards with Xilinx FPGAs running in microTCA crate with card interconnections via crate backplanes and optical links operating at up to 10 Gbps. Prototype cards with Virtex-6 and Virtex-7 FPGAs have been built and software frameworks for operation and monitoring developed. The physics goals, hardware architectures, and software will be described in this talk. More details can be found in a separate poster at this conference.
We present a design for the Phase-1 upgrade of the Compact Muon Solenoid (CMS) calorimeter trigger system composed of FPGAs and Multi-GBit/sec links that adhere to the mu TCA crate Telecom standard. ...The upgrade calorimeter trigger will implement algorithms that create collections of isolated and non-isolated electromagnetic objects, isolated and non-isolated tau objects and jet objects. The algorithms are organized in several steps with progressive data reduction. These include a particle cluster finder that reconstructs overlapping clusters of 2 x 2 calorimeter towers and applies electron identification, a cluster overlap filter, particle isolation determination, jet reconstruction, particle separation and sorting.
In LHC (Large Hadron Collider) Run 2, the center-of-mass energy for proton-proton collisions is 13 TeV and the instantaneous luminosity has doubled. This has made it more challenging to trigger on ...interesting events since the number of interactions per crossing (pileup) is significantly larger than in LHC Run 1. The Compact Muon Solenoid (CMS) experiment has installed, commissioned, and is operating the second stage of a two-stage upgrade to the Calorimeter Trigger. This upgrade has improved the trigger algorithms so that the trigger thresholds remain low and physics data is not compromised. The stage-1, which replaced the original CMS Global Calorimeter Trigger, operated successfully in 2015. The completely new stage-2 has replaced the entire calorimeter trigger in 2016 with AMC form-factor boards and optical links operating in a microTCA chassis. It required that updates to the calorimeter back-ends, the source of the trigger primitive data, were also fully installed and operational. The stage-2 system's boards use Xilinx Virtex-7 690T FPGAs and have hundreds of links operating at up to 10 Gbps to maximize data throughput. In addition, a new time-multiplexed architecture was implemented and extensive firmware and software development was necessary. The final commissioning, operation, and performance of the stage-2 calorimeter trigger in 2016 proton collisions are described.
The Large Hadron Collider (LHC) at CERN has begun the physics program for Run 2. The center-of-mass energy has risen from 8 to 13 TeV and the instantaneous luminosity will increase for both proton ...and heavy-ion running. This will make it more challenging to trigger on interesting events since the number of interactions per crossing (pile-up) and the overall trigger rate will be significantly larger than LHC Run 1. The Compact Muon Solenoid (CMS) experiment has installed a two-stage upgrade to their Calorimeter Trigger to ensure that the trigger rates can be controlled and the thresholds can stay low, so that physics data collection will not be compromised. The first-stage upgrade is installed and includes new electronics and duplicated optical links so that the LHC Run 1 CMS calorimeter trigger is still functional and algorithms can be developed while data taking continues. The second-stage will fully replace the calorimeter trigger at CMS with AMC form-factor boards and an optical link system, and require that the updates to the calorimeter back-ends, the source of the trigger primitives, are also installed and operational. The stage-2 system's boards will utilize Xilinx Virtex 7 FPGAs and have hundreds of high-speed links operating at up to 10 Gbps to maximize data throughput. The integration, commissioning, operation, and performance of stage-1 for 2015 data taking and stage-2 for triggering in 2016 will be described.
The CMS Level-1 calorimeter trigger is being upgraded in two stages to maintain performance as the LHC increases pile-up and instantaneous luminosity in its second run. In the first stage, improved ...algorithms including event-by-event pile-up corrections are used. New algorithms for heavy ion running have also been developed. In the second stage, higher granularity inputs and a time-multiplexed approach allow for improved position and energy resolution. Data processing in both stages of the upgrade is performed with new, Xilinx Virtex-7 based AMC cards.
The first measurement of the cross section for top-quark pair production in pp collisions at the Large Hadron Collider at center-of-mass energy inline image has been performed using a data sample ...corresponding to an integrated luminosity of 3.1+/-0.3 pb super(-1) recorded by the CMS detector. This result utilizes the final state with two isolated, highly energetic charged leptons, large missing transverse energy, and two or more jets. Backgrounds from Drell-Yan and non-W/Z boson production are estimated from data. Eleven events are observed in the data with 2.1+/-1.0 events expected from background. The measured cross section is 194+/-72(stat.)+/-24(syst.)+/-21(lumi.) pb, consistent with next-to-leading order predictions.
The electronics for the regional calorimeter trigger (RCT) of the Compact Muon Solenoid experiment (CMS) at the Large Hadron Collider (LHC) have been produced and tested, and are being integrated ...with the experiment at CERN. The RCT hardware consists of 18 double-sided crates containing custom boards, ASICs, and backplanes all running at 160 MHz frequency. The RCT receives 8 bit energies and a data quality bit on 1008 4times1.2 Gbaud copper links from the hadron calorimeter (HCAL) and the electromagnetic calorimeter (ECAL) trigger primitive generators (TPGs), accepting new events every 25 ns. RCT processing determines the jet region energies, and, sorted isolated and non-isolated electromagnetic objects, which are sent to the CMS global calorimeter trigger (GCT) for further processing. Before installation, both self-tests, using RCT jet capture card, and integration tests with TPG and GCT systems were performed. Their results of these tests and the RCT installation experience are described.
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