First measurements of the performance of the Barrel RPC system in CMS

During the summer 2006, a first integrated test of a part of the CMS experiment was performed at CERN collecting a data sample of several millions of cosmic rays events. A fraction of the Resistive Plate Chambers system was successfully operated. Results on the RPC performance are reported

Performance of the CMS Level-1 trigger in proton-proton collisions at √s = 13 TeV

At the start of Run 2 in 2015, the LHC delivered proton-proton collisions at a center-of-mass energy of 13\TeV. During Run 2 (years 2015–2018) the LHC eventually reached a luminosity of 2.1× 10$^{34}$ cm$^{-2}$s$^{-1}$, almost three times that reached during Run 1 (2009–2013) and a factor of two larger than the LHC design value, leading to events with up to a mean of about 50 simultaneous inelastic proton-proton collisions per bunch crossing (pileup). The CMS Level-1 trigger was upgraded prior to 2016 to improve the selection of physics events in the challenging conditions posed by the second run of the LHC. This paper describes the performance of the CMS Level-1 trigger upgrade during the data taking period of 2016–2018. The upgraded trigger implements pattern recognition and boosted decision tree regression techniques for muon reconstruction, includes pileup subtraction for jets and energy sums, and incorporates pileup-dependent isolation requirements for electrons and tau leptons. In addition, the new trigger calculates high-level quantities such as the invariant mass of pairs of reconstructed particles. The upgrade reduces the trigger rate from background processes and improves the trigger efficiency for a wide variety of physics signals

FPGA-based novel real-time evaluation and data quality monitoring system for tokamak high-performance GEM soft X-ray diagnostic

International audienceBased on literature review data quality monitoring topic is often being simplified in case of tokamak diagnostic systems. In previous publications Authors presented a novel model of real-time evaluation and data quality monitoring (EDQM) sub-system for use in physics experiments, mostly related to tokamak plasma measurements. The implementation of model is done in scope of monitoring raw output signals from Gas Electron Multiplier detectors used in FPGA-based soft X-ray diagnostics. System is designed to work in the real-time feedback loop for parameters control of tokamak in scope of achieving long-term plasma stability. In the paper are described results of application the DQM engine from measurements with 112-channel GEM detector and real radiation sources (isotopes, X-ray tube). The discussion provided in article covers the usefulness of applied novel EDQM techniques: technical and statistical, in scope of detection of new, corrupted output signals from the GEM detector when working under hard environment conditions. The presented in the paper results indicates the ability of the detection of subtle system defects (e.g. detector, electronics), resulting in the significant corruption of the output products of measured radiation: energy and topological spectra. This is especially important for the systems working in the real-time feedback loop. The novel approach of detection new malformed signals with ability to automatically discard those phenomena from further analysis is also described. In the summary there are described benefits of usage of the proposed novel DQM approach with indication of another unique work for further CPU extensions of the EDQM sub-system providing complex FPGA-CPU high-performance data quality monitoring unit. The EDQM system is planned to be installed in GEM SXR diagnostics on WEST tokamak

Architecture of the upgraded BCM1F Backend Electronics for Beam Conditions and Luminosity measurement - hardware and firmware

The Beam Radiation Instrumentation and Luminosity Project of the CMS experiment, consists of several beam monitoring systems. One system, the upgraded Fast Beams Condition Monitor, is based on 24 single crystal CVD diamonds with a double-pad sensor metallization and a custom designed readout. Signals for real time monitoring are transmitted to the counting room, where they are received and processed by new back-end electronics designed to extract information on LHC collision, beam induced background and activation products. Data in the form of histograms is transmitted to the DAQ. The system architecture and the signal processing algorithms will be presented.SummaryThe Fast Beam Conditions Monitor (BCM1F) detector is a part of the CMS Beam Radiation Instrumentation and Luminosity Project (BRIL). The increased performance expected of the LHC with energy of up to 14 TeV, higher luminosity and 25 ns bunch spacing is a challenge for the detector systems and increase the importance of real-time beam monitoring at high rates. The BCM1F is designed to monitor the flux and timing of particles originating from the proton-proton interactions and machine-induced-background (MIB) particles using 24 single crystal CVD diamond sensors positioned at a distance of ±1.8 m from the interaction point. Signals from the detectors are shaped and amplified by a front-end pre-amplifier ASIC and transmitted through optical fibers.The BCM1F back-end electronics is designed to receive signals from the detector via 48 optical channels. The architecture of the system is based on MicroTCA technology. It assumes using 12 AMC cards with a single FMC connector for receiving signals from the detector, 2 AMCs for measurement of the Beam Pick-up Timing for Experiments (BPTX) signals and 2 AMCs for the slow control of the front-end electronics. For signals digitizing 12 FMC mezzanines with 4 channels, 8 bit ADCs at a sampling rate 1.25 GS/s are considered to be used. The mezzanines configured in 1 channel operating mode at 5 GS/s sampling rate can be used for the BPTX signals measurement. The slow control module will use 2 FMC mezzanines with 8 SFP/SFP+ cages.The firmware design must be capable of processing signals at very high input rates (270 MHz) without introducing any dead time. It will provide information about collisions, MIB and activation products. Samples will be processed in FPGAs on AMC carrier boards, put into histograms and sent to the BRIL data acquisition system. The data processing algorithm is being designed to be able to recognize signal peaks from the detector with a minimum time resolution of ~12 ns, which corresponds to the maximum overlap of two pulses that can be recognized as separate from the ASIC. The single pulse FWHM is 10 ns. Various methods of the amplitude and time measurement are being tested. Information about a peak occurrence will be stored in histograms total number of counts in time, and in amplitude. Additionally one orbit of RAW data is possible to be collected every Lumi Nibble (2^12 orbits) and sent to the DAQ, for efficiency studies. The data storage will consume most of the FPGA memory resources (up to 85pct) that hence the more complex algorithms can be used only for offline analysis.The structure of the system, data flow and considered algorithms will be presented along with the current status of the readout system development

New Fast Beam Conditions Monitoring (BCM1F) system for CMS

The CMS Beam Radiation Instrumentation and Luminosity (BRIL) project is composed of several systems providing the experiment protection from adverse beam conditions while also measuring the online luminosity and beam background. Although the readout bandwidth of the Fast Beam Conditions Monitoring system (BCM1F - one of the faster monitoring systems of the CMS BRIL), was sufficient for the initial LHC conditions, the foreseen enhancement of the beams parameters after the LHC Long Shutdown-1 (LS1) imposed the upgrade of the system. This paper presents the new BCM1F, which is designed to provide real-time fast diagnosis of beam conditions and instantaneous luminosity with readout able to resolve the 25 ns sub-bunch structure