The CMS electromagnetic calorimeter upgrade: high-rate readout with precise time and energy resolution

The electromagnetic calorimeter (ECAL) of the CMS detector has played an important role in the physics program of the experiment, delivering outstanding performance throughout data taking. The high-luminosity LHC will pose new challenges. The four to five-fold increase of the number of interactions per bunch crossing will require superior time resolution and noise rejection capabilities. For these reasons the electronics readout has been completely redesigned. A dual gain trans-impedance amplifier and an ASIC providing two 160 MHz ADC channels, gain selection, and data compression will be used in the new readout electronics. The trigger decision will be moved off-detector and will be performed by powerful and flexible FPGA processors, allowing for more sophisticated trigger algorithms to be applied. The upgraded ECAL will be capable of high-precision energy measurements throughout HL-LHC and will greatly improve the time resolution for photons and electrons above 10 GeV.

Developing signals to trigger adaptation to sea-level rise

© 2018 The Author(s). Published by IOP Publishing Ltd. Dynamic adaptive policy pathways (DAPP) is emerging as a 'fit-for-purpose' method for climate-change adaptation planning to address widening future uncertainty and long planning timeframes. A key component of DAPP is to monitor indicators of change such as flooding and storm events, which can trigger timely adaptive actions (change pathway/behavior) ahead of thresholds. Signals and triggers are needed to support DAPP - the signal provides early warning of the emergence of the trigger (decision-point), and the trigger initiates the process to change pathway before a harmful adaptation-threshold is reached. We demonstrate a new approach to designing signals and triggers using the case of increased flooding as sea level continues to rise. The flooding frequency is framed in terms of probable timing of several events reaching a specific height threshold within a set monitoring period. This framing is well suited to adaptive planning for different hazards, because it allows the period over which threshold exceedances are monitored to be specified, and thus allows action before adaptation-thresholds are reached, while accounting for the potential range of timing and providing a probability of premature warning, or of triggering adaptation too late. For our New Zealand sea level case study, we expect early signals to be observed in 10 year monitoring periods beginning 2021. Some urgency is therefore required to begin the assessment, planning and community engagement required to develop adaptive plans and associated signals and triggers for monitoring. Worldwide, greater urgency is required at tide-dominated sites than those adapted to large storm-surges. Triggers can be designed with confidence that a change in behavior pathway (e.g. relocating communities) will be triggered before an adaptation-threshold occurs. However, it is difficult to avoid the potential for premature adaptation. Therefore, political, social, economic, or cultural signals are also needed to complement the signals and triggers based on coastal-hazard considerations alone.

Developing signals to trigger adaptation to sea-level rise

© 2018 The Author(s). Published by IOP Publishing Ltd. Dynamic adaptive policy pathways (DAPP) is emerging as a 'fit-for-purpose' method for climate-change adaptation planning to address widening future uncertainty and long planning timeframes. A key component of DAPP is to monitor indicators of change such as flooding and storm events, which can trigger timely adaptive actions (change pathway/behavior) ahead of thresholds. Signals and triggers are needed to support DAPP - the signal provides early warning of the emergence of the trigger (decision-point), and the trigger initiates the process to change pathway before a harmful adaptation-threshold is reached. We demonstrate a new approach to designing signals and triggers using the case of increased flooding as sea level continues to rise. The flooding frequency is framed in terms of probable timing of several events reaching a specific height threshold within a set monitoring period. This framing is well suited to adaptive planning for different hazards, because it allows the period over which threshold exceedances are monitored to be specified, and thus allows action before adaptation-thresholds are reached, while accounting for the potential range of timing and providing a probability of premature warning, or of triggering adaptation too late. For our New Zealand sea level case study, we expect early signals to be observed in 10 year monitoring periods beginning 2021. Some urgency is therefore required to begin the assessment, planning and community engagement required to develop adaptive plans and associated signals and triggers for monitoring. Worldwide, greater urgency is required at tide-dominated sites than those adapted to large storm-surges. Triggers can be designed with confidence that a change in behavior pathway (e.g. relocating communities) will be triggered before an adaptation-threshold occurs. However, it is difficult to avoid the potential for premature adaptation. Therefore, political, social, economic, or cultural signals are also needed to complement the signals and triggers based on coastal-hazard considerations alone.

Evaluation of a high-performance storage buffer with 3D XPoint devices for the DUNE data acquisition system

The DUNE detector is a neutrino physics experiment that is expected to take data starting from 2028. The data acquisition (DAQ) system of the experiment is designed to sustain several TB/s of incoming data which will be temporarily buffered while being processed by a software based data selection system. In DUNE, some rare physics processes (e.g. Supernovae Burst events) require storing the full complement of data produced over 1-2 minute window. These are recognised by the data selection system which fires a specific trigger decision. Upon reception of this decision data are moved from the temporary buffers to local, high performance, persistent storage devices. In this paper we characterize the performance of novel 3DXPoint SSD devices under different workloads suitable for high-performance storage applications. We then illustrate how such devices may be applied to the DUNE use-case: to store, upon a specific signal, 100 seconds of incoming data at 1.5 TB/s distributed among 150 identical units each operating at approximately 10GB/s.

Upgrade of the KEDR detector DAQ system

The KEDR experiment is ongoing at the VEPP-4M e+e− collider at Budker INP in Novosibirsk. The collider center of mass energy range covers a wide spectrum from 2 to 11 GeV. Most of the up-to-date statistics were taken at the lower end of the energy range around the charmonia region. Planned activities at greater energies up to the bottomonia would lead to a significant increase of event recording rates and accelerator backgrounds, thus stressing the existing DAQ and trigger systems beyond their limits. The described DAQ upgrade plan includes: the redesign of the trigger electronics using modern components to improve the trigger decision time; the development of new readout processors using ethernet connections; new software for collecting events and electronics management; high level of parallelization of data transfers and events processing; improved reliability based on readout computing cluster with redundancy. The upgraded DAQ system is going to be very flexible and could be considered as a concept prototype of the projected BINP Super Charm-Tau Factory.

The Data Acquisition System of the Na62 Experiment at Cern

The aim of the NA62 experiment is to study the extreme rare kaon decay K+ ? π+vv and to measure its branching ratio with a 10% accuracy. In order to do so, a very high intensity beam from the CERN SPS is used to produce charged kaons whose decay products are detected by many detectors installed along a 60 m decay region. The NA62 Data Acquisition system (DAQ) exploits a multi-level trigger system; following a Level0 (L0) trigger decision, 1 MHz data rate from about 60 sources is read by a PC-farm, the partial event is built and then passed through a series of Level1 (L1) algorithms to further reduce the trigger rate. Events passing this level are completed with the missing, larger, data sources (~400 sources) at the rate of 100 KHz. The DAQ is built around a high performance ethernet network interconnecting the detectors to a farm of 30 servers. After an overall description of the system design and the main implementation choices that allowed to reach the required performance and functionality, this paper describes the overall behaviour of the DAQ in the 2017 data taking period. It then concludes with an outlook of possible improvements and upgrades that may be applied to the system in the future.

Data Acquisition and Software for the ATLAS Tile Calorimeter Phase-II Upgrade Demonstrator

After a series of upgrades, the High Luminosity LHC (HL-LHC) will have an instantaneous luminosity of 5-7 times larger than the LHC design value. The readout electronics of the ATLAS Tile Calorimeter (TileCal) will undergo a substantial upgrade during the Phase-II upgrade to accommodate the HL-LHC requirements. After the Phase-II upgrade, the TileCal detector signals will be digitized by on-detector electronics and transferred to the the TileCal PreProcessors (TilePPr), which is a part of the off-detector electronics. In the TilePPr, the digitized data will be stored in pipeline buffers and be packed and readout to the Front-End Link eXchange (FELIX) system upon receiving a trigger decision. At the same time, the energy information will be reconstructed from the detector data and transferred to the Level-1 Calorimeter Trigger (L1Calo) system in different granularity for every bunch crossing. The TileCal Demonstrator is designed to evaluate the performance of the TileCal with new readout electronics without compromising the present data taking. This contribution describes in detail the data processing and the hardware, firmware, software components of the TileCal Demonstrator system, together with the results of beam tests performed at CERN.

Performance Analysis of MRC Receivers with Adaptive Modulation and Coding in Rayleigh Fading Correlated Channels with Imperfect CSIT

This paper addresses the performance analysis of an adaptive wireless link with one antenna transmitter and a multiple antenna maximum-ratio combining (MRC) receiver. Two main assumptions are used in this paper: (1) Rayleigh fading correlated channels (i.e., MRC branch correlation) and (2) imperfect (outdated) channel state information at the transmitter (CSIT) side. The main contribution of this work lies in the derivation of analytic expressions (in terms of a series expansion) of the statistics of correct packet reception conditional on the decisions made by the transmitter based on outdated CSIT. The novelty of this derivation is the joint modelling of spatially correlated branches, imperfect CSIT, and adaptive modulation based on threshold-trigger decision. Contrary to common belief, the results presented here suggest that spatial correlation not always affects the performance of the MRC receiver: at low signal-to-noise ratio (SNR), correlation can improve performance rather than degrading it. In contrast, at high SNR, correlation is found to always degrade performance. At high SNR, correlation tends to worse the degrading effects of imperfect CSIT, particularly when the number of antennas increases. Imperfect CSIT causes errors in the assignment of MCSs, thus reducing throughput performance. These errors become more evident in the high SNR regime, particularly when the values of branch correlation and the number of antennas increase.