Trigger System Research Articles

Design of a high performance Digital data AcquIsition SYstem (DAISY) for innovative nuclear experiments

A dedicated digital data acquisition (DAQ) system has been developed for innovative nuclear data measurements, from time-of-flight to irradiation experiments as well as other basic nuclear physics experiments. The DAQ system is based on fast digitizers with 14 bits resolution and 1 GS/s sampling rate for reliable pulse shape discrimination, energy and timing resolution measurements. Thanks to the high throughput provided by the PCIe bus, data can be processed at CPU or co-processor level, thus allowing great flexibility and reliability. The use of an external clock system and a dedicated triggering system guarantee a very precise synchronization with other possible subsystems in any experimental setup. Finally, its modularity allows to build a flexible and scalable system.

Measurement and Analysis of the Switching Transients in 500 kV Pumped Storage Power Plants

Pumped storage power plants (PSPPs) are among the most efficient and practical large-scale energy storage systems. In recent years, several transformer failures have occurred in PSPPs, and transient overvoltage is considered a potential reason for failure. However, there is a lack of field measurement results for transient analysis. In this paper, a switching transient measurement system and multipoint synchronous triggering system were developed. Field measurements were carried out in three PSPPs. According to the measurement results, the maximum amplitude of the switching overvoltage was 630.6±46.5 kV. The shortest front time was 76±7.6 ns. The largest steepness was 1130±140.8 kV/μs. A simulation model was built to analyze three phenomena in the transient, including multistep waveform, overvoltage peak, and power transformer demagnetization. The measurement and analysis results are beneficial for the improvement of simulation modeling. It is helpful to pinpoint potentially damaging transients for equipment manufacturers and designers of PSPPs.

Vitrimeric shape memory polymer-based fingertips for adaptive grasping.

The variability in the shapes and sizes of objects presents a significant challenge for two-finger robotic grippers when it comes to manipulating them. Based on the chemistry of vitrimers (a new class of polymer materials that have dynamic covalent bonds, which allow them to reversibly change their mechanical properties under specific conditions), we present two designs as 3D-printed shape memory polymer-based shape-adaptive fingertips (SMP-SAF). The fingertips have two main properties needed for an effective grasping. First, the ability to adapt their shape to different objects. Second, exhibiting variable rigidity, to lock and retain this new shape without the need for any continuous external triggering system. Our two design strategies are: 1) A curved part, which is suitable for grasping delicate and fragile objects. In this mode and prior to gripping, the SMP-SAFs are straightened by the force of the parallel gripper and are adapted to the object by shape memory activation. 2) A straight part that takes on the form of the objects by contact force with them. This mode is better suited for gripping hard bodies and provides a more straightforward shape programming process. The SMP-SAFs can be programmed by heating them up above glass transition temperature (54°C) via Joule-effect of the integrated electrically conductive wire or by using a heat gun, followed by reshaping by the external forces (without human intervention), and subsequently fixing the new shape upon cooling. As the shape programming process is time-consuming, this technique suits adaptive sorting lines where the variety of objects is not changed from grasp to grasp, but from batch to batch.

Performance of the MALTA telescope

MALTA is part of the Depleted Monolithic Active Pixel sensors designed in Tower 180 nm CMOS imaging technology. A custom telescope with six MALTA planes has been developed for test beam campaigns at SPS, CERN, with the ability to host several devices under test. The telescope system has a dedicated custom readout, online monitoring integrated into DAQ with realtime hit map, time distribution and event hit multiplicity. It hosts a dedicated fully configurable trigger system enabling to trigger on coincidence between telescope planes and timing reference from a scintillator. The excellent time resolution performance allows for fast track reconstruction, due to the possibility to retain a low hit multiplicity per event which reduces the combinatorics. This paper reviews the architecture of the system and its performance during the 2021 and 2022 test beam campaign at the SPS North Area.

Impact-Based Flood Early Warning for Rural Livelihoods in Uganda

Abstract Anticipatory actions are increasingly being taken before an extreme flood event to reduce the impacts on lives and livelihoods. Local contextualized information is required to support real-time local decisions on where and when to act and what anticipatory actions to take. This study defines an impact-based, early-warning trigger system that integrates flood forecasts with livelihood information, such as crop calendars, to target anticipatory actions better. We demonstrate the application of this trigger system using a flood case study from the Katakwi District in Uganda. First, we integrate information on the local crop cycles with the flood forecasts to define the impact-based trigger system. Second, we verify the impact-based system using historical flood impact information and then compare it with the existing hazard-based system in the context of humanitarian decisions. Study findings show that the impact-based trigger system has an improved probability of flood detection compared with the hazard-based system. There are fewer missed events in the impact-based system, while the trigger dates are similar in both systems. In a humanitarian context, the two systems trigger anticipatory actions at the same time. However, the impact-based trigger system can be further investigated in a different context (e.g., for livelihood protection) to assess the value of the local information. The impact-based system could also be a valuable tool to validate the existing hazard-based system, which builds more confidence in its use in informing anticipatory actions. The study findings, therefore, should open avenues for further dialogue on what the impact-based trigger system could mean within the broader forecast-based action landscape toward building the resilience of at-risk communities.

Impact of radon on personal contamination monitors at the exit of the restricted controlled areas in EDF nuclear power plant

Background: Between 2008 and 2017, EDF has progressively replaced its old Personal Contamination Monitors (PCM) with a new generation to strengthen the control of the workers at the exit of the restricted controlled areas. One of the novelties of the new PCM generation is the introduction of gamma channels which, coupled to the beta channel, allows a more reliable and more precise measurement. The new PCM also includes a better monitoring of the C2 portals alarms triggering system, a greater detection surface to minimize the dead zone and carries out morphological compensation to take into account the attenuation of the gamma background by the body. This new PCM is very efficient and capable of detecting low contamination activities. The sensitivity of this monitoring system is such that the solid progeny of 222Rn deposited on clothes (such as the 214Pb and the 214Po) could in some cases be detected and triggered the C2 portals alarm. Objective: In order to quantify the impact of radon (222Rn) and its progeny on the C2 portals triggers, a specific study has been conducted. Beyond the physical aspect, several purposes are targeted: (1) to provide quantitative explanations about the C2 alarms attributed to radon and determine which channels are more affected by the 222Rn progeny; (2) to determine the existence of a relation between C2 alarms and high 222Rn volume activity; (3) to optimize practices at the exit of the Restricted Controlled Areas (RCA), for example, adapt waiting time before control in PCM. The study consisted in measuring the activity of radon progeny deposited on several types of suits used in EDF Nuclear Power Plants (NPPs). To assess the impact of the 222Rn, several factors have been studied such as the 222Rn exposure time, the 222Rn concentration and the nature of textile fibers constituting clothes. For this study, several facilities from the Laboratoire de Physique des deux infinis de Bordeaux (LP2i Bordeaux) have been used, including a 222Rn emanation standard source and various emanation chambers between 60 L and 750 L. A specific calibration method to characterize radon progenies deposited has been developed (see Sects. 2.4 and 3). The 222Rn concentration in the sample exposure environment is verified both using a commercial (see Sects. 2.4 and 3) and experimental high sensitivity radon detectors. The measurements of the 222Rn progeny on clothes are made immediately after exposure by gamma spectrometry control on a High Purity Germanium (HPGe) detector. This experiment has been carried out at the PRISNA measurement platform (Plateforme Régionale Interdisciplinaire de Spectrométrie Nucléaire en Aquitaine) located in LP2I Bordeaux. Conclusions: In this study, several phenomena have been highlighted for a better understanding of the C2 portal triggering. We validate that in presence of 222Rn volume concentration activity lower than 300 Bq/m3, an alarm in beta channels of C2 portals can be triggered because of the presence of the radon progeny on clothes. The triggering of the gamma channels could appear only if the volume concentration activity of radon is higher than 3000 Bq/m3. The results obtained in this study could led to optimize and harmonize the practices at the exit of Restricted Controlled Area (RCA) like adapt waiting time before control in PCM.

Vertical water entry of a hydrophobic sphere into waves: Numerical computations and experiments

The water entry cavity evolution and its flow structures for a sphere interacting with periodic waves are investigated numerically and experimentally. The large eddy simulation is applied in the simulation to accurately capture the turbulent flow near the surface and within the cavity of the sphere. An overset mesh-based numerical wave tank is developed, integrating an overset mesh with a method for generating regular waves, to ensure high resolution simulation of velocity fields around the water entry cavity in waves. To validate the numerical model, a physical experiment system is developed, featuring a free-falling setup and an asynchronous pulse trigger system. This experimental setup allows for precise control of the vertical water entry of a sphere at a predetermined phase of a periodic wave. The computed cavity shape and the sphere motion are in good agreement with the experimental results. Notably, the hydrodynamic forces exerted on the sphere exhibit two distinct peaks at the moment of impact and the pinch-off of the cavity, respectively. The gas-phase force acting on the dry surface of the sphere, as the cavity forms and evolves, experiences significant fluctuations along the direction of the sphere's descent. These fluctuations are caused by the accelerating gas flow prior to the pinch-off of the cavity. The changes of the hydrodynamic forces on the sphere for the cases of different water entry phase locations of waves and Froude numbers are discussed.

Power distribution board: Quality control, quality assurance and testing

During the second Large Hadron Collider Long Shutdown, the Liquid Argon calorimeter of the ATLAS experiment at CERN has been upgraded with a new trigger readout electronics which provides digital information with higher granularity to the ATLAS trigger system. In particular, the new LAr Trigger Digitizer Boards will process and digitize the "Super Cells" (group of readout calorimeters cells) and send the processed data to the back-end electronics. The Power Distribution Board is a mezzanine board that provides the power distribution to the LTDB. Before being installed inside the detector these mezzanines must be tested for proper operation, particularly the proper functioning of the voltage regulators that are used to deliver the correct supply voltage. This article will show and discuss the control tests performed on the power distribution boards.

The NectarCAM timing system

NectarCAM is a Cherenkov camera which is going to equip the Medium-Sized Telescopes (MST) of the northern site of the Cherenkov Telescope Array Observatory (CTAO). NectarCAM is equipped with 265 modules, each consisting of 7 photo-multiplier tubes (PMTs), a Front-End Board and a local camera trigger system used for data acquisition. This paper addresses the timing performance of NectarCAM which are crucial to reduce the noise in shower images and improve image cleaning as well as to discriminate between gamma-ray photons and cosmic-ray background and finally to allow coincidence identification with neighboring telescopes for stereoscopic operations. Verification tests of the system have been performed in a dark room using various light sources to illuminate the first NectarCAM unit. The resulting timing precision and accuracy of the trigger arrival relative to a laser source, of individual and multiple pixel signals have been studied and are shown to comply to CTAO requirements.

Commissioning and first performances of the ALICE MID RPCs

ALICE (A Large Ion Collider Experiment) at the CERN Large Hadron Collider (LHC) is designed to study pp and Pb–Pb collisions at ultra-relativistic energies. ALICE is equipped with a Muon Spectrometer (MS) to study the heavy charmonia in pp and heavy ion collisions via their muonic decay. At first, in the LHC Run 1 and 2 the selection of interesting events for muon physics in the MS was performed with a dedicated Muon Trigger system based on Resistive Plate Chambers (RPCs) operated in maxi-avalanche mode. During the LHC Long Shutdown 2 (LS2), ALICE underwent a major upgrade of its apparatus in order to fully profit from the increased luminosity of Pb–Pb collisions (from 20 kHz in Run 2 to 50 kHz in Run 3). Many sub-systems of the ALICE experiment are now running in continuous readout (triggerless). In this context the Muon Trigger system became the Muon IDentifier (MID). In order to reduce the RPC ageing and to increase the rate capability, it was decided to use a new front-end electronics FEERIC with a pre-amplification stage to minimize the charge released per hit inside the gas gap. A description of the MID upgrades, together with the results and performances of the RPCs from the commissioning, is presented in this paper.

System Design and Prototyping for the CMS Level-1 Trigger at the High-Luminosity LHC

The High-Luminosity Large Hadron Collider (HL-LHC) is planned to offer a very ambitious physics program, with high-precision measurement and evaluation of the Standard Model (SM), and motivate the searches for new physics. The efficient data collection and precise events reconstruction in the harsh environment of 200 proton-proton interactions are vital for achieving the success of the HL-LHC program. To realize these requirements, the CMS detector has planned to completely replace the data acquisition (DAQ) and trigger system. The CMS Level-1 trigger system will handle the enormous detector input bandwidth of 63 Tbps with the maximum output rate of 750 kHz and is desired to complete the processing within 12.5 μs. For this purpose, CMS has planned to replace the Phase-1 μTCA-based processor boards and crates with an ATCA form factor. Each ATCA board will host Xilinx large UltraScale/UltraScale+ family FPGA and support more than a hundred high-speed optical links (~28 Gbps), capable of meeting the high bandwidth and processing requirements of HL-LHC. Along with the advancement in hardware, the Level-1 trigger system will employ highly modular, flexible, and adequately sophisticated algorithms that were only possible in offline reconstruction, such as the particle-flow algorithm. The modular and flexible architecture will help address the HL-LHC dynamic physics requirements. We will discuss the details of system design, prototyping, and the algorithms employed for the Level-1 trigger system.

Performance Evaluation of Modern Time-Series Database Technologies for the ATLAS Operational Monitoring Data Archiving Service

The Trigger and Data Acquisition system of the ATLAS [1] experiment at the Large Hadron Collider [2] at CERN is composed of a large number of distributed hardware and software components which provide the data-taking functionality of the overall system. During data-taking, huge amounts of operational data are created in order to constantly monitor the system. The Persistent Back-End for the ATLAS Information System of TDAQ (P-BEAST) is a system based on a custom-built time-series database. It archives any operational monitoring data published online, resulting in about 18 TB of highly compacted and compressed raw data per year. P-BEAST provides command line and programming interfaces for data insertion and retrieval, including integration with the Grafana platform. Since P-BEAST was developed, several promising database technologies for efficiently working with time-series data have been made available. A study to evaluate the possible use of these recent database technologies in the P-BEAST system was performed. First, the most promising technologies were selected. Then, their performance was evaluated. The evaluation strategy was based on both synthetic read and write tests, and on realistic read patterns (e.g., providing data to a set of Grafana dashboards currently used to monitor ATLAS). All the tests were executed using a subset of ATLAS operational monitoring data, archived during the LHC Run II. The details of the testing procedure and of the testing results, including a comparison with the current P-BEAST service, are presented.

A Cu2+ triggered reversible photochromic system: the structure photochromic response relationship study and potential applications.

Fifteen rhodamine B hydrazide hydrazone (RhBHH) derivatives (compounds a-o) with various substituent groups at different position and their photochromic property triggered by Cu2+ were studied to illustrate the structure photochromic response relationship (SPRR). Three of them (compounds f-h) with a para-position hydroxyl group and two meta-position halogen substituents display Cu2+-triggered photochromic which is significantly different from the previous reports. It was found that halogen atoms, which were generally considered to have no remarkable regulation effect, exhibited great influences on the photochromic behaviour of RhBHH derivatives. Detail photochromic properties of the developed photochromic system were revealed by using compound g as the model substrate, and only Cu2+ displayed high selective trigger effect. Good reversible photochromic phenomenon was observed after stimulated with visible light irradiation and dark (or heat) bleaching consecutively. Furthermore, this photochromic system could be used in the preparation of photochromic glass, special security ink, molecular logic gate and two-dimensional code for security information storage.

Progress in Design and Testing of the DAQ and Data-Flow Control for the Phase-2 Upgrade of the CMS Experiment

The second phase of the LHC, the High-Luminosity LHC, is scheduled to start in 2029, after a shutdown during which the beam intensity and focusing will be significantly upgraded. For this HL-LHC era, also the CMS detector will receive an extensive upgrade, primarily to maintain its physics performance at increasing pileup. The Phase-2 CMS Level-1 trigger rate will increase to 750 kHz, for an estimated data rate in excess of 50 Tbit/s. The Phase-2 CMS off-detector electronics will be based on the ATCA standard, with back-end boards receiving the detector data from the on-detector front-ends via custom, radiation-tolerant, optical links. The CMS Phase-2 data acquisition design tightens the integration between trigger control and data flow, extending the synchronous regime of the DAQ system. At the core of the design is the DAQ and Timing Hub, a custom ATCA hub card forming the bridge between the different, detector-specific, control and readout electronics and the common timing, trigger, and control systems. The overall synchronisation and data flow of the experiment is handled by the Trigger and Timing Control and Distribution System. For increased flexibility during commissioning and calibration runs, the design of the Phase-2 trigger and timing distribution system breaks with the traditional distribution tree, in favour of a configurable network connecting multiple independent control units to all off-detector endpoints. In order to reduce the number of custom hardware designs required, the DAQ hardware is designed such that it can also be used to implement the Trigger and Timing Control and Distribution System.

Upgrade of Online Storage and Express-Reconstruction System for the Belle II Experiment

The Belle II experiment started to take data of electron-positron collisions provided by the SuperKEKB accelerator, with all subdetectors from March 2019. The collected data are selected by a software-based high-level trigger system and stored on online storage. After storing the data, the online storage sends the data to an express-reconstruction system for semi-real-time data quality monitoring and event display. The high-level trigger system is built on the ZeroMQ networking library, but the online storage and express-reconstruction system are built on the ring buffer and TCP/IP socket-based framework. To improve the stability and future maintainability, we develop the new online storage and express-reconstruction system using the ZeroMQ library. The new systems have a few additional improvements. First, the online storage supports the ROOT output file format with compression. This reduces the online file size, necessary network bandwidth for the online-to-offline file transfer, and offline computing resource usage. Second, two types of express-reconstruction systems are prepared based on the high-level trigger results; for randomly sampled data and for physics-flagged data by the high-level trigger system. The separate express-reconstruction system can process a larger number of statistics of physics-flagged events.

Research on the Development Path of Professional Teachers from the Perspective of Undergraduate Vocational Education

In view of the opportunities and challenges brought by vocational education at the undergraduate level to professional teachers in higher vocational schools, combined with the current situation of teacher development in our school, we will explore the development path of professional teachers from the perspective of front-line teachers. Firstly, it analyses the hierarchical structure of professional teacher development, and analyses the stages that are easier to break through in the hierarchical structure. Then, it establishes the triggering system for professional teacher development, and demonstrates the necessity of triggering the internal driving force of teacher development from the perspective of classroom, emotion and environment. Finally, a professional teacher development accumulation matrix is established by taking engineering measurement technology professional teachers as an example, in order to learn from and inspire other vocational teachers in the period of rapid development, and keep in mind the original intention and mission together.

Streaming DAQ Software Prototype at the J-PARC Hadron Experimental Facility

In recent years, experiments in particle physics and nuclear physics have required faster data collection systems and advanced trigger systems as the beam intensity has been increased. The current data acquisition (DAQ) system at the Japan Proton Accelerator Research Complex (J-PARC) Hadron Experimental Facility (HEF) uses fixed- and low-latency triggers with dedicated hardware to reduce data and event-building software that merges data into a single endpoint. This conventional DAQ system is expected to be inadequate for future experiments. It has to be replaced with a new simplified but powerful system called streaming DAQ, which collects the detector signals and filters them with software running on many computers. Therefore, we developed a prototype of streaming DAQ software for the J-PARC HEF using FairMQ and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Redis</i> as middleware. The key features include simplicity and a low learning cost to develop and be operated by a small number of people. The software can be used in a fully streaming readout system and in the triggered DAQ and the combined DAQ of the hardware and software triggers.

Performance-linked visual feedback slows response times during a sustained attention task

In the present study, we tested a visual feedback triggering system based on real-time tracking of response time (RT) in a sustained attention task. In our task, at certain points, brief visual feedback epochs were presented without interrupting the task itself. When these feedback epochs were performance-linked—meaning that they were triggered because participants were responding more quickly than usual—RTs were slowed after the presentation of feedback. However, visual feedback epochs displayed at predetermined times that were independent of participants’ performance did not slow RTs. Results from a second experiment support the idea that this is not simply a return to baseline that would have occurred had the feedback not been presented, but instead suggest that the feedback itself was effective in altering participants’ responses. In a third experiment, we replicated this result across with both written word feedback and visual symbolic feedback, as well as in cases where the participant was explicitly told that the feedback was linked to their performance. All together, these data provide insight into potential mechanisms for detecting and disrupting lapses in sustained attention without interrupting a continuous task.

A Miniaturized Sealed-Off Double-Gap Pseudospark Switch for High Power and High Repetition Rate Pulsed Discharge Applications

Pulsed power systems can deliver high peak power in a micro/nano-second timescale to various loads in scientific and industrial applications, whose performances are significantly influenced by the pulsed discharge switch. This paper presents the development and comprehensive tests of a miniaturized sealed-off pseudospark switch. The structure of double-gap and multi-channel is adopted to achieve the high hold-off voltage and high current capacity. In single pulse tests, the influence of pressure in the switch is analyzed. As the pressure increases, values of multiple parameters decrease, like self-breakdown voltage, trigger delay, and voltage dropping time. In a wide pressure range, trigger jitter is below 3 ns, and the minimum is < 1 ns. At low pressure, the transient voltage across two gaps becomes inconsistent, and two types of current quenching are observed, which are related to processes occurring on cathode surface. In repetitive pulse tests, the direct repetitive operation is up to 3.5 kHz while higher repetition rate is limited by the trigger system. In double-pulse tests, the maximum repetition rate can be higher than 8 kHz for 40 kV pulsed voltage. Meanwhile, the insulation recovery speed is higher at lower pressure, and as the time delay between two pulses increases, the second pulse breakdown voltage increases nonlinearly. In high current tests, the switch is also used in metal wire explosion experiments and operates at the condition of 30 kV/40 kA for more than 104 shots without performance degradation. Further lifetime tests point out that the switch can work for >106 shots stably at moderate current. Experiments prove that the designed switch has superior performances including high hold-off voltage (>50 kV), low jitter (<1 ns), high repetition rate (>3.5 kHz), high peak current (>40 kA), long lifetime (>106 shots) and miniaturized size.

Deep machine learning for the PANDA software trigger

Deep machine learning methods have been studied for the software trigger of the future PANDA experiment at FAIR, using Monte Carlo simulated data from the GEANT-based detector simulation framework PandaRoot. Ten physics channels that cover the main physics topics, including electromagnetic, exotic, charmonium, open charm, and baryonic reaction channels, have been investigated at four different anti-proton beam momenta. Different classification concepts and network architectures have been studied. Finally a residual convolutional neural network with four residual blocks in a binary classification scheme has been chosen due to its extendability, performance and stability. The presented study represents a feasibility study of a completely software-based trigger system. Compared to a conventional selection method, the deep machine learning approach achieved a significant efficiency gain of up to 200%, while keeping the background reduction factor at the required level of 1/1000. Furthermore, it is shown that the use of additional input variables can improve the data quality for subsequent analysis. This study shows that the PANDA software trigger can benefit greatly from the deep machine learning methods.