Level Trigger Research Articles

A Bayesian model for truncated regression for the estimation of empirical ground-motion models

We present a Bayesian model for the estimation of ground-motion models that allows one to account for truncated data. Truncated data occurs in ground-motion model development because instruments do not record continuously, but only when triggered. The model is formulated as a multi-level model and incorporates event and station terms. The model considers truncation on one variable [e.g., peak ground acceleration (PGA)], and models the joint occurrence of PGA and other ground-motion intensity measures, while conditioning on the truncation for PGA. Initially, we perform numerical experiments on simulated data sets and show that not taking data truncation into account leads to biased models. Regressions using the proposed truncated model can recapture the functions used in the simulation well, and perform comparable to alternative approaches used in the past. Subsequently, we show the impact of the truncated model on observed ground-motion data representing moderate and high trigger levels, 2–4 gal and 10 gal, respectively. Differences to a model that does not take truncation into account occur at larger distances, and are more severe for the high trigger level data. For untruncated regression, the values of the standard deviations are underestimated.

The Phase-2 Upgrade of the Hardware Trigger of CMS at the LHC

The CMS experiment uses a two-level triggering system consisting of the Level-1, instrumented by custom-design hardware boards, and the High Level Trigger, a streamlined version of the offline reconstruction software running on a computer farm. The upgrade of the collider to the “High-Luminosity LHC”, which will deliver a luminosity of 5−7.5 × 1034 cm−2s−1, corresponding to 140–200 pileup events, also necessitates a complete upgrade of the trigger system to make optimal use of the data. An important difference from the present system will be the fact that after the upgrade, information from the silicon strip tracker will be available already for the Level-1 Trigger. This will allow CMS to use so-called “particle flow” objects, i.e. signals seen not only in one subdetector but put together from all available subdetectors, resulting in much sharper efficiency turn-on curves for trigger objects. Also, trigger rates will rise both at Level-1 (from 100 kHz to 750 kHz) and at the High-Level Trigger (from 1 kHz to 7.5 kHz). At the same time, more sophisticated algorithms will be available at Level-1. To make this possible, the latency—the processing time available for arriving at the Level-1 trigger decision—will increase significantly. Machine-learning techniques such as Boosted Decision Trees have already started to be implemented in the trigger electronics and will occupy a more important place in the future. The use of High-Level Synthesis (HLS) tools will allow physicists to formulate trigger requirements in a language closer to that of data analysis. To avoid missing unexpected signatures from New Physics, studies are underway to employ anomaly detection using autoencoders.

Urinary Organophosphate Metabolite Concentrations and Pregnancy Outcomes among Women Conceiving through in Vitro Fertilization in Shanghai, China.

Background:Animal studies suggest that pesticide exposure elicits endocrine changes, increases embryo implantation failure, and decreases litter size. However, only a few epidemiological studies have evaluated the effects of pesticides on the outcomes of in vitro fertilization (IVF) pregnancies.Objectives:This study examined the associations between preconception organophosphate pesticides (OP) exposure and pregnancy outcomes among women undergoing IVF in a Chinese population.Methods:This study included 522 women with infertility who underwent IVF. Women were recruited from a prospective study, the China National Birth Cohort (CNBC), from Shanghai, China, between July 2017 and December 2018. Demographic and clinical information were collected from medical records and through questionnaires. Preconception exposure to OP was assessed by measuring six nonspecific dialkylphosphate (DAP) metabolites [diethylthiophosphate (DETP), diethylphosphate (DEP), diethyldithiophosphate (DEDTP), dimethylthiophosphate (DMTP), dimethylphosphate (DMP), dimethyldithiophosphate (DMDTP)] in urine samples collected at recruitment. Generalized estimating equation (GEE) models were used to evaluate the associations between OP and pregnancy outcomes.Results:Compared with women in the lowest quartile () of individual DEP and (the sum of DMP, DMTP, DEP, and DETP), women in the highest quartile () had lower odds of successful implantation, clinical pregnancy, and live birth, and most of the negative trends were significant (). There were no significant associations between urinary DAP concentrations and early IVF outcomes, including total and mature oocyte counts, best embryo quality, fertilization, trigger levels, and endometrial wall thickness.Conclusion:Preconception OP exposure was inversely associated with successful implantation, clinical pregnancy, and live birth in women who underwent IVF. https://doi.org/10.1289/EHP7076

Design, performance and perspective of the NA62-RICH

NA62 is an experiment designed to measure the branching fraction of the ultra-rare decay of the positively charged kaon into a pion and a neutrino-antineutrino pair. The specialties of its Ring Imaging Cherenkov detector (RICH) are the muon-pion separation, the sub-nanosecond timing and the participation in the lowest level trigger of the experiment. These characteristics made the NA62-RICH crucial for the physics data taking that run in the three-year period 2016–2018. Two aspects are currently under consideration to increase the impact of RICH in the broad NA62 physics program: a better time resolution to cope with higher intensity beam and the online extraction of high level features to be used in the trigger logic. This paper describes the RICH detector and presents its possible upgrades.

Triggering long-lived particles in HL-LHC and the challenges in the first stage of the trigger system

Triggering long-lived particles (LLPs) at the first stage of the trigger system is very crucial in LLP searches to ensure that we do not miss them at the very beginning. The future High Luminosity runs of the Large Hadron Collider will have increased number of pile-up events per bunch crossing. There will be major upgrades in hardware, firmware and software sides, like tracking at level-1 (L1). The L1 trigger menu will also be modified to cope with pile-up and maintain the sensitivity to physics processes. In our study we found that the usual level-1 triggers, mostly meant for triggering prompt particles, will not be very efficient for LLP searches in the 140 pile-up environment of HL-LHC, thus pointing to the need to include dedicated L1 triggers in the menu for LLPs. We consider the decay of the LLP into jets and develop dedicated jet triggers using the track information at L1 to select LLP events. We show in our work that these triggers give promising results in identifying LLP events with moderate trigger rates.

Development of the ATLAS Liquid Argon (LAr) Calorimeter readout electronics for the HL-LHC

To meet new trigger and data acquisition (TDAQ) buffering requirements and withstand the high expected radiation doses at the High-Luminosity LHC, the ATLAS Liquid Argon Calorimeter readout electronics will be upgraded. The triangular calorimeter signals are amplified and shaped by analog electronics over a dynamic range of 16 bits, with low noise and excellent linearity. Developments of low-power preamplifiers and shapers in the 130 nm CMOS technology are ongoing to meet these requirements. In order to digitize the analog signals on two gains after shaping, a radiation-hard, low-power 40 MHz 14-bit Analog-to-Digital Converter (ADC) is developed using a pipeline + Successive Approximation Register (SAR) architecture in the 65 nm CMOS technology. Characterization of the prototypes of the front-end components show good promise to fulfill all the requirements. The signals will be sent at 40 MHz to the off detector electronics, where Field-Programmable Gate Arrays (FPGAs) connected through high-speed links will perform energy and time reconstruction through the application of corrections and digital filtering. Reduced data will be sent with low latency to the first level trigger, while the full data will be buffered until the reception of trigger accept signals. The data-processing, control and timing functions will be realized by dedicated boards connected through Advanced Telecommunications Computing Architecture (ATCA) crates.

The Phase-2 Upgrade of the CMS Outer Tracker

The Large Hadron Collider(LHC), at CERN will undergo major upgrades to be able to deliver peak instantaneous luminosities of about 5−7.5×1034cm−2s−1 by 2027. This High Luminosity upgrade of the LHC (HL-LHC) is expected to deliver a total of about 3000−4000fb−1 during ten years of operation. At the nominal instantaneous luminosity of the HL-LHC, a single bunch crossing will produce 140−200 proton–proton collisions. The current CMS strip tracker and the CMS Phase-1 pixel detector will not be able to survive the harsh operating conditions of the HL-LHC period. The CMS experiment will install a new silicon tracker for the HL-LHC. The Phase-2 Outer Tracker(OT) will feature increased radiation hardness, higher granularity and track separation and compatibility with higher data rates and a longer trigger latency. In addition, the OT will provide tracking information to the Level-1 trigger, allowing trigger rates to be kept at a sustainable level without sacrificing physics potential. To achieve this, the OT will be made up of modules with two closely spaced sensors read out by a single ASIC. The ASIC will correlate data from both sensors to form short track segments called stubs, to be used in tracking at Level-1. In this contribution, the design of the CMS Phase-2 OT, the technological choices and highlights of the research and development activities will be reported.

CoCo issuance and bank fragility

The promise of contingent convertible capital securities (CoCos) as a ”bail-in” solution has been the subject of considerable theoretical analysis and debate, but little is known about their effects in practice. We undertake the first comprehensive empirical analysis of bank CoCo issues, a market segment that comprises over 730 instruments totaling $521 billion. Four main findings emerge: (1) the propensity to issue a CoCo is higher for larger and better capitalized banks; (2) CoCo issues result in a statistically significant decline in issuers’ CDS spread, indicating that they generate risk-reduction benefits and lower costs of debt (this is especially true for CoCos that convert into equity, have mechanical triggers, and are classified as Additional Tier 1 instruments); (3) CoCos with only discretionary triggers do not have a significant impact on CDS spreads; and (4) CoCo issues have no statistically significant impact on stock prices, except for principal write-down CoCos with a high trigger level, which have a positive effect.

Upgraded electronics of the ATLAS hadronic Tile Calorimeter for the High Luminosity LHC

The ATLAS hadronic Tile Calorimeter will undergo major upgrades to the on- and off-detector electronics in preparation for the High Luminosity program of the Large Hadron Collider (HL-LHC) in 2026, so that the system can cope with the HL-LHC increased radiation levels and out-of-time pileup. The on-detector electronics of the upgraded system will continuously digitize and transmit all photo-multiplier signals to the off-detector systems at a 40 MHz rate. The off-detector electronics will store the data in pipeline buffers, produce digital hadronic tower sums for the ATLAS Level-0 trigger system, and read out selected events. The modular on-detector electronics feature radiation-tolerant commercial off-the-shelf components and redundant design to minimize single points of failure. The timing, control and communication interface with the off-detector electronics is implemented with modern Field Programmable Gate Arrays and high speed fibre optic links running up to 9.6 Gbps.

ATLAS LAr calorimeter performance in LHC Run 2

Liquid argon (LAr) sampling calorimeters are employed by ATLAS for all electromagnetic calorimetry in the pseudorapidity region |η| < 3.2, and for hadronic and forward calorimetry in the region from |η| = 1.5 to |η| = 4.9. In the first LHC run a total luminosity of 27 fb−1 has been collected at center-of-mass energies of 7–8 TeV. After detector consolidation during a long shutdown, Run 2 started in 2015 and 147 fb−1 of data at a center-of-mass energy of 13 TeV have been recorded. In order to realize the level-1 trigger acceptance rate of 100 kHz in Run 2 data taking, the number of read-out samples recorded and used for the energy and the time measurement has been modified from five to four while keeping the expected performance. The well calibrated and highly granular LAr calorimeter reached its design values both in energy measurement as well as in direction resolution. This contribution gives an overview of the detector operation, hardware improvements, changes in the monitoring and data quality procedures, to cope with increased pileup, as well as the achieved performance, including the calibration and stability of the electromagnetic scale, noise level, response uniformity and time resolution.

Development of the Level-1 track trigger with Central Drift Chamber detector in Belle II experiment and its performance in SuperKEKB 2019 Phase 3 operation

The Level-1 trigger system (TRG) in the Belle II experiment is designed to summarize real-time sub-detectors information by using FPGA chips for the central data acquisition (DAQ) system, and it includes several sub-trigger systems for triggering various types of physics events in interest. The main focus in this report is CDCTRG: the track trigger system with Central Drift Chamber (CDC) detector, which is responsible for the real-time trajectory reconstruction of charged particles with various algorithms: Track-Segment Finder, 2D, 3D, Neuro-3D, and short tracking. CDCTRG is necessary for specific types of physics, such as hadronic and μ pair. This paper will introduce the design of the hardware system and algorithm implementation in FPGAs. Development, validation and performance of each CDCTRG module during SuperKEKB beam collision operation will also be discussed in detail.

FPGA-based tracking for the CMS Level-1 trigger using the tracklet algorithm

The high instantaneous luminosities expected following the upgrade of the Large Hadron Collider (LHC) to the High-Luminosity LHC (HL-LHC) pose major experimental challenges for the CMS experiment. A central component to allow efficient operation under these conditions is the reconstruction of charged particle trajectories and their inclusion in the hardware-based trigger system. There are many challenges involved in achieving this: a large input data rate of about 20–40 Tb/s processing a new batch of input data every 25 ns, each consisting of about 15,000 precise position measurements and rough transverse momentum measurements of particles (“stubs”); performing the pattern recognition on these stubs to find the trajectories; and producing the list of trajectory parameters within 4 μs. This paper describes a proposed solution to this problem, specifically, it presents a novel approach to pattern recognition and charged particle trajectory reconstruction using an all-FPGA solution. The results of an end-to-end demonstrator system, based on Xilinx Virtex-7 FPGAs, that meets timing and performance requirements are presented along with a further improved, optimized version of the algorithm together with its corresponding expected performance.

ECAL trigger performance in Run 2 and improvements for Run 3

The CMS electromagnetic Calorimeter (ECAL) is a high resolution crystal calorimeter operating at the CERN LHC. It is responsible for the identification and precise reconstruction of electrons and photons in CMS, which were crucial in the discovery and subsequent characterization of the Higgs boson. It also contributes to the reconstruction of tau leptons, jets, and calorimeter energy sums, which are vital components of many CMS physics analyses. The ECAL trigger system employs fast digital signal processing algorithms to precisely measure the energy and timing information of ECAL energy deposits recorded during LHC collisions. These trigger primitives are transmitted to the Level-1 trigger system at the LHC collision rate of 40 MHz. These energy deposits are then combined with information from other CMS sub-detectors to determine whether the event should trigger the readout of the data from CMS to be transmitted to the High-Level Trigger and eventually to permanent storage. This note will summarize the ECAL trigger performance achieved during LHC Run 2 (2015–2018). It will describe the methods that are used to provide frequent calibrations of the ECAL trigger primitives during LHC operation. These are needed to account for radiation-induced changes in crystal and photodetector response and to maintain stable trigger rates and efficiencies up to 0|η|=3.. They also minimize the spurious triggering on direct signals in the photodetectors used in the barrel region (|η|<1.48). Both of these effects have increased relative to LHC Run 1 (2009–2012), due to the higher luminosities experienced in Run 2. Further improvements in the energy and time reconstruction of the CMS ECAL trigger primitives are being explored for LHC Run 3 (2021–2023), using additional features implemented in the on-detector readout. These are particularly focused on improving the performance at the highest instantaneous luminosities (which will reach or exceed 2⋅ 1034 cm−2 s−1 in Run 3) and in the most forward regions of the calorimeter (|η|>2.5), where the effects of detector aging will be the greatest. The main features of these improved algorithms will be described and preliminary estimates of the expected performance gains will be presented.

Development of the micro-resistive WELL discs for the CMD-3 tracking system

Micro-pattern gas technology is planned for the upgrade of the tracking system of the CMD-3 detector at the VEPP-2000 electron-positron collider in Budker INP. The upgrade includes a new thin tracking cylinder that consists of two tracking layers at a radius of 32 to 33 cm with coordinate resolution close to 0.5 mm in z-direction (along the beam axis) and trigger segments of about 1 cm in the transverse plane. The other part of new coordinate subsystem includes two end-cap discs with active area between radius of 5 cm and 25 cm, that should provide spatial resolution close to 1 mm in both directions as well as the first level trigger signal. For these two subsystems we plan to use micro-RWELL technology because it allows much simpler assembling of large cylindrical detector and large discs due to more rigid glass-fiber support as compared to the triple GEM technology.

Normal autonomic neurophysiology of postural orthostatic tachycardia and recommended physiological assessments in postural orthostatic tachycardia syndrome.

The current surge of interest in postural orthostatic tachycardia syndrome commonly known as POTS requires good knowledge of the very complex physiology involved, but this is currently lacking. The often overlooked normal physiology of orthostasis is reviewed including the definition of normal postural orthostatic tachycardia. An illustrated functional anatomy that embeds orthostatic tachycardia within the learned and skilful motor functions in the human population is presented. The four physiological phases of orthostasis and the role of tachycardia are described in a laboratory‐controlled and progressive orthostatic stress in normal human volunteers. Standardized surrogate measures of autonomic control were used to quantify the trigger level for excessive tachycardia and the minimum autonomic control required to sustain viable arterial blood pressure during severe orthostatic stress in normal human volunteers. Tachycardia during orthostasis is part of a “democratic” contribution by four cardiovascular parameters of which the chronotropic function of the heart is just one of the parameters contributing toward cardiovascular compensation. It is adjusted during orthostasis in proportion to contributions from the other three parameters, namely inotropic function of the heart, windkessel vascular resistance and venous vascular capacitance. The physiological effects of the two stressors during orthostasis, gravity and isometric contraction of skeletal muscles are reviewed. A model of how the four cardiovascular parameters are regulated during orthostasis to achieve proportionate contributions is proposed emphasizing the necessity to quantify individual contributions from all these four parameters. Any one or more of these parameters may be compromised due to disease requiring disproportionate contribution of the prevailing magnitude of orthostatic tachycardia in an individual. It therefore requires neurophysiological assessment of the autonomic regulation of all the four cardiovascular parameters to assess the condition fully. We recommend here some current and novel neurophysiological methods that use modern medical technology to quantify laboratory standardized surrogate measures of some of these cardiovascular parameters including central parasympathetic regulation in postural orthostatic tachycardia syndrome.

Poultry litter as potential source of pathogens and other contaminants in groundwater and surface water proximal to large-scale confined poultry feeding operations

Manure from livestock production has been associated with the contamination of water resources. To date, research has primarily focused on runoff of these contaminants from animal operations into surface water, and the introduction of poultry-derived pathogenic zoonoses and other contaminants into groundwater is under-investigated. We characterized pathogens and other microbial and chemical contaminants in poultry litter, groundwater, and surface water near confined poultry feeding operations (chicken layer, turkey) at 9 locations in Iowa and one in Wisconsin from May and June 2016. Results indicate that poultry litter from large-scale poultry confined feeding operations is a likely source of environmental contamination and that groundwater is also susceptible to such poultry-derived contamination. Poultry litter, groundwater, and surface water samples had detections of viable bacteria growth (Salmonella spp., enterococci, staphylococci, lactobacilli), multi-drug resistant Salmonella DT104 flost and int genes, F+ RNA coliphage (group I and IV), antibiotic resistance genes (ARGs; blaDHA, blaOXA-48, blaTEM, blaCMY-2, tetM), phytoestrogens (biochanin A, daidzein, formononetin), and a progestin (progesterone). In addition, mcr-1 (a colistin ARG), was detected in a groundwater sample and in another groundwater sample, antibiotic resistant isolates were positive for Brevibacterium spp., a potential signature of poultry in the environment. Detectable estrogenicity was not measured in poultry litter, but was observed in 67% of the surface water samples and 22% were above the U.S. Environmental Protection Agency trigger level of 1 ng/L. The transport of microbial pathogens to groundwater was significantly greater (p < 0.001) than the transport of trace organic contaminants to groundwater in this study. In addition to viable pathogens, several clinically important ARGs were detected in litter, groundwater, and surface water, highlighting the need for additional research on sources of these contaminants in livestock dominated areas.

Proposal of an Airport Pavement Maintenance Management System for Cape Verde

In order to ensure safe and efficient operation of aircrafts, airport operators are faced with the need to maintain airport runway, taxiway and apron pavements in good condition, within a given budget. In this context, this paper describes the first developments and the methodological approach of a doctoral work with the following objectives: to improve and validate in-vehicle technique for pavement inspection using GNSS, video image capture and Geographic Information System, increasing the degree of automation of pavement distress identification; to develop a procedure for the definition of preventive maintenance strategies for airport pavements, adapted to Cape Verde airport system, using modelling techniques to predict pavement performance and definition of service and trigger levels; and also to develop or calibrate an existing computer application that can be used as a decision support tool.

Development of the ATLAS Liquid Argon Calorimeter Readout Electronics for the HL-LHC

Following new Trigger and Data AcQuisition (TDAQ) buffering and rate requirements as well as the high radiation doses and the pileup conditions of the High-Luminosity LHC, the ATLAS Liquid Argon Calorimeter electronics will be upgraded to readout the 182,500 calorimeter cells at 40 MHz with 16 bit dynamic range. The triangular calorimeter signals are amplified and shaped by the analogue electronics over a dynamic range of 16 bits, with low noise and excellent linearity. Developments of low-power preamplifiers and shapers to meet these requirements are ongoing in CMOS 130 nm. In order to digitize the analogue signals on two gains after shaping, radiation-hard, low-power 40 MHz 14-bit ADCs are developed using a SAR architecture in 65 nm CMOS. Characterization of the first prototypes of the Front-End components show good promise to fulfill all the requirements. The signals will be sent at 40 MHz to the off-detector electronics, that will make use of FPGAs connected through high-speed links to perform energy and time reconstruction through the application of digital filtering and appropriate corrections. Reduced data are sent with low latency to the first level trigger, while the full data are buffered until the reception of trigger accept signals. The data-processing, control and timing functions will be realized by dedicated boards connected through ATCA crates. Results of tests of the first prototypes of Front-End components will be presented, along with design studies on the performance of the off-detector readout system.

Fast inference of Boosted Decision Trees in FPGAs for particle physics

We describe the implementation of Boosted Decision Trees in the hls4ml library, which allows the translation of a trained model into FPGA firmware through an automated conversion process. Thanks to its fully on-chip implementation, hls4ml performs inference of Boosted Decision Tree models with extremely low latency. With a typical latency less than 100 ns, this solution is suitable for FPGA-based real-time processing, such as in the Level-1 Trigger system of a collider experiment. These developments open up prospects for physicists to deploy BDTs in FPGAs for identifying the origin of jets, better reconstructing the energies of muons, and enabling better selection of rare signal processes.

Investigation of the Power Consumption of the PETsys TOFPET2 ASIC

In state-of-the-art positron emission (PET) tomography systems, application-specific integrated circuits (ASICs)are commonly used to precisely digitize the signals of analog silicon photo-multipliers (SiPMs). However, when operating PET electronics in a magnetic resonance (MR) system, one faces the challenge of mutual interference of these imaging techniques. To prevent signal deterioration along long analog signal lines, PET electronics with a low power consumption digitizing the signals close to the SiPMs are preferred. In this study, we evaluate the power consumption of the TOFPET2 ASIC. Its power consumption ranges from 3.6 to 7.2 mW/channel as a function of the input stage impedance and discriminator noise settings. We present an analytical model allowing to compute the power consumption of a given ASIC configuration. The configured input stage impedance and discriminator noise have an impact on the coincidence resolution time, energy resolution, and photon trigger level. Since the TOFPET2 ASIC delivers state-of-the-art performance with a power consumption similar or even lower than other ASICs typically used for PET applications, it is a favorable candidate to digitize the signals of SiPMs in future simultaneous PET/MR systems.