Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “trigger efficiency”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Simulations for the global quantum efficiency of MicroBooNE optical units

The MicroBooNE detector uses scintillation light from particle interactions in liquid argon as a data acquisition trigger. This scintillation light has wavelengths in the vacuum ultra violet (VUV) range, and must be converted into visible light to be detected by photomultiplier tubes (PMTs). To convert the light, MicroBooNE uses wavelength shifting plates coated with Tetraphenyl butadiene (TPB) placed in front of its PMTs. While basic tuning of this plate-PMT system is sufficient for triggering, precise calibration of the system makes additional calorimetry possible. This note will outline how a photon simulation which accounts for the geometry and optical details of the MicroBooNE detector can accompany a measurement of observed photoelectrons in a plate-PMT test stand, and how the results may be used to determine a "global quantum efficiency" for the plate-PMT system. This global quantum efficiency is one required ingredient for improving the capabilities of the light collection system.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2023

Interfacial Connections between Organic Perovskite/n + Silicon/Catalyst that Allow Integration of Solar Cell and Catalyst for Hydrogen Evolution from Water

Abstract The rapidly increasing solar conversion efficiency (PCE) of hybrid organic–inorganic perovskite (HOIP) thin‐film semiconductors has triggered interest in their use for direct solar‐driven water splitting to produce hydrogen. However, application of these low‐cost, electronic‐structure‐tunable HOIP tandem photoabsorbers has been hindered by the instability of the photovoltaic‐catalyst‐electrolyte (PV+E) interfaces. Here, photolytic water splitting is demonstrated using an integrated configuration consisting of an HOIP/n + silicon single junction photoabsorber and a platinum (Pt) thin film catalyst. An extended electrochemical (EC) lifetime in alkaline media is achieved using titanium nitride on both sides of the Si support to eliminate formation of insulating silicon oxide, and as an effective diffusion barrier to allow high‐temperature annealing of the catalyst/TiO 2 ‐protected‐n + silicon interface necessary to retard electrolytic corrosion. Halide composition is examined in the (FA 1‐x Cs x )PbI 3 system with a bandgap suitable for tandem operation. A fill factor of 72.5% is achieved using a Spiro‐OMeTAD‐hole‐transport‐layer (HTL)‐based HOIP/n + Si solar cell, and a high photocurrent density of −15.9 mA cm −2 (at 0 V vs reversible hydrogen electrode) is attained for the HOIP/n + Si/Pt photocathode in 1 m NaOH under simulated 1‐sun illumination. While this thin‐film design creates stable interfaces, the intrinsic photo‐ and electro‐degradation of the HOIP photoabsorber remains the main obstacle for future HOIP/Si tandem PEC devices.

08 HYDROGEN↗
DOE OSTI2019

Efficient Solution Methods for Large-scale Optimization Problems Constrained by Time-dependent Partial Differential Equations (Final Report)

The objectives of this project are to devise and analyze efficient solvers for several classes of PDE- constrained optimization problems. The project was initially focused on, but not restricted to time- dependent PDE-constraints such as parabolic equations, time-dependent fluid flows (Navier-Stokes equations), hyperbolic equations (Burgers equation, shallow water equations). Other constraints considered are PDEs with stochastic coefficients. Additional elements of interest are the handling of problems with control and/or state inequality constraints or non-differentiable regularization terms, and boundary controls. A direction of work not initially listed among the goals, which was triggered by conversations with DOE scientists from the Sandia National Labs, is to develop efficient solvers for optimization- based domain-decomposition PDE-solvers. Also targeted in the project are a number of technical issues necessary for facilitating the integration of the methods resulted from this project with existing high-performance packages developed at DOE national labs; this integration is expected to further enable the scientific community to use the novel methods. An example of such a task is the need to develop algebraic multigrid (AMG) versions of the algorithms. A list of accomplishments in several areas is detailed as well as a list of publications.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2025

Hexagonal Boron Nitride: Physical Properties, Hydride Vapor‐Phase Epitaxy Growth of Large‐Diameter Quasi‐Bulk Wafers and Applications

Hexagonal boron nitride ( h ‐BN), with its ultrawide bandgap and 2D structure, holds an immense promise for advanced semiconductor applications. Scaling bulk crystals to large‐diameter wafers, crucial for complex device fabrication, remains a challenge with high temperature, high pressure, and metal flux solution methods. To address this, recent efforts have focused on hydride vapor‐phase epitaxy (HVPE) for producing large diameter thick h ‐BN quasi‐bulk wafers, reaching hundreds of micrometers. These HVPE‐grown quasi‐bulk crystals exhibit excellent c ‐axis long‐range order. Notably, the in‐plane mobility‐lifetime products for both electrons and holes surpass 10 −4 cm 2 V −1 , which are two orders of magnitude greater than the out‐of‐plane (vertical) values, highlighting the potential for high‐performance devices leveraging superior lateral transport. Lateral detectors fabricated from 100 μm thick B‐10 enriched h‐ BN wafers have achieved a record 60% thermal neutron detection efficiency. Based on its physical properties, h‐ BN appears to be an outstanding material of choice for light‐triggered electronic power switches capable of supporting high ‐ voltage and high ‐ power operations. These recent advancements in large‐diameter h ‐BN quasi‐bulk crystal growth, enabled by HVPE, pave the way for applications spanning deep UV photonics, high‐power electronics, high‐efficiency neutron detection, and quantum information technologies, establishing h ‐BN as both a versatile active semiconductor and an ideal substrate.

Jiang, Hongxing [Department of Electrical and Comp↗
DOE OSTI2019

Efficient Modeling of HIL Multi-Grid System for Scalability & Concurrency in CPS Security Testbed

Cyber-event-triggered power grid blackout compels utility operators to intensify cyber-aware and physics-constrained recovery and restoration process. Recently, coordinated cyber attacks on the Ukrainian grid witnessed such a cyber-event-triggered power system blackout. Various cyber-physical system (CPS) testbeds have attempted with multitude designs to analyze such interdependent events and evaluate remedy measures. However, resource constraints and modular integration designs have been significant barriers while modeling large-scale grid models (scalability) and multi-grid isolated models (concurrency) under a single real-time execution environment for the hardware-in-the-loop (HIL) CPS security testbeds. This paper proposes a meticulous design and effective modeling for simulating large-scale grid models and multi-grid isolated models in a HIL realtime digital simulator environment integrated with industry-grade hardware and software systems. We have used our existing HIL CPS security testbed to demonstrate scalability by the realtime performance of a Texas-2000 bus US synthetic grid model and concurrency by the real-time performance of simultaneous ten IEEE-39 bus grid models and an IEEE-118 bus grid model. The experiments demonstrated significant results by 100% realtime performance with zero overruns, low latency while receiving and executing control signals from SEL Relays via IEC-61850 protocol and low latency while computing and transmitting grid data streams including stability measures via IEEE C37.118 synchrophasor data protocol to SEL Phasor Data Concentrators.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2017

Hydrogen Bonding Rescues Overpotential in Seven-Coordinated Ru Water Oxidation Catalysts

In this paper, we describe the synthesis, structural characterization, and redox properties of two new Ru complexes containing the dianionic potentially pentadentate [2,2':6',2"-terpyridine]-6,6"-dicarboxylate (tda 2– ) ligand that coordinates Ru at the equatorial plane and with additional pyridine or dmso acting as monondentate ligand in the axial positions: [Ru II (tda-κ-N 3 O)(py)(dmso)], 1 II and [Ru III (tda-κ-N 3 O 2 )(py)(H 2 O) ax ] + , 2 III (H 2 O) + . Complex 1 II has been characterized by single-crystal XRD in the solid state and in solution by NMR spectroscopy. The redox properties of 1 II and 2 III (H 2 O) + have been thoroughly investigated by means of cyclic voltammetry and differential pulse voltammetry. Complex 2 II (H 2 O) displays poor catalytic activity with regard to the oxidation of water to dioxygen, and its properties have been analyzed on the basis of foot of the wave analysis and catalytic Tafel plots. The activity of 2 II (H 2 O) has been compared with related water oxidation catalysts (WOCs) previously described in the literature. Despite its moderate activity, 2 II (H 2 O) constitutes the cornerstone that has triggered the rationalization of the different factors that govern overpotentials as well as efficiencies in molecular WOCs. The present work uncovers the interplay between different parameters, namely, coordination number, number of anionic groups bonded to the first-coordination sphere of the metal center, water oxidation catalysis overpotential, p K a and hydrogen bonding, and the performance of a given WOC. It thus establishes the basic principles for the design of efficient WOCs operating at low overpotentials.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Nonadiabatic dynamics with classical trajectories: The problem of an initial coherent superposition of electronic states

Advances in coherent light sources and development of pump–probe techniques in recent decades have opened the way to study electronic motion in its natural time scale. When an ultrashort laser pulse interacts with a molecular target, a coherent superposition of electronic states is created and the triggered electron dynamics is coupled to the nuclear motion. A natural and computationally efficient choice to simulate this correlated dynamics is a trajectory-based method where the quantum-mechanical electronic evolution is coupled to a classical-like nuclear dynamics. These methods must approximate the initial correlated electron–nuclear state by associating an initial electronic wavefunction to each classical trajectory in the ensemble. Different possibilities exist that reproduce the initial populations of the exact molecular wavefunction when represented in a basis. We show that different choices yield different dynamics and explore the effect of this choice in Ehrenfest, surface hopping, and exact-factorization-based coupled-trajectory schemes in a one-dimensional two-electronic-state model system that can be solved numerically exactly. Furthermore, this work aims to clarify the problems that standard trajectory-based techniques might have when a coherent superposition of electronic states is created to initialize the dynamics, to discuss what properties and observables are affected by different choices of electronic initial conditions and to point out the importance of quantum-momentum-induced electronic transitions in coupled-trajectory schemes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Towards a self-driving trigger at the LHC: adaptive response in real time

Real-time data filtering and selection—or trigger—systems at high-throughput scientific facilities such as the experiments at the Large Hadron Collider must process extremely high-rate data streams under stringent bandwidth, latency, and storage constraints. Yet these systems are typically designed as static, hand-tuned menus of selection criteria grounded in prior knowledge and simulation. In this work, we further explore the concept of a self-driving trigger, an autonomous data-filtering framework that reallocates resources and adjusts thresholds dynamically in real-time to optimize signal efficiency, rate stability, and computational cost as instrumentation and environmental conditions evolve. We introduce a benchmark ecosystem to emulate realistic collider scenarios and demonstrate real-time optimization of a menu including canonical energy sum triggers as well as modern anomaly-detection algorithms that target non-standard event topologies using machine learning. Using simulated data streams and publicly available collision data from the Compact Muon Solenoid experiment, we demonstrate the capability to dynamically and automatically optimize trigger performance under specific cost objectives without manual retuning. Our adaptive strategy shifts trigger design from static menus with heuristic tuning to intelligent, automated, data-driven control, unlocking greater flexibility and discovery potential in future high-energy physics analyses.

Emami, Shaghayegh [Michigan U.] (ORCID:00090007589↗
DOE OSTI2023

CHEETAH: Compact High Efficiency Electrically Tunable Amplifier (Final Report)

The goal of this project was to develop a new type of optically triggered, high speed and high power switch for radiofrequency applications with potential to exceed current state-of-the-art power and bandwidth. This device operates under a new operation principle, where discrete packets of charge carriers are generated with defined size. These are then swept out of the device at high enough fields to prevent diffusion and expansion of these packets. Individual pulse widths are determined by the spatial extent of these packets and their drift velocity, which would enable control over both amplitude and frequency by control of the initial packet size, illumination intensity, and applied voltage. This effort demonstrated this new mode of operation, while uncovering a new regime of pulse compression using negative differential mobility (NDM) semiconductors such as GaAs, where the output electrical pulse is substantially shorter than the input optical pulse.

42 ENGINEERING↗
DOE OSTI2025

Optoelectronic polymer memristors with dynamic control for power-efficient in-sensor edge computing

Abstract As the demand for edge platforms in artificial intelligence increases, including mobile devices and security applications, the surge in data influx into edge devices often triggers interference and suboptimal decision-making. There is a pressing need for solutions emphasizing low power consumption and cost-effectiveness. In-sensor computing systems employing memristors face challenges in optimizing energy efficiency and streamlining manufacturing due to the necessity for multiple physical processing components. Here, we introduce low-power organic optoelectronic memristors with synergistic optical and mV-level electrical tunable operation for a dynamic “control-on-demand” architecture. Integrating signal sensing, featuring, and processing within the same memristors enables the realization of each in-sensor analogue reservoir computing module, and minimizes circuit integration complexity. The system achieves 97.15% fingerprint recognition accuracy while maintaining a minimal reservoir size and ultra-low energy consumption. Furthermore, we leverage wafer-scale solution techniques and flexible substrates for optimal memristor fabrication. By centralizing core functionalities on the same in-sensor platform, we propose a resilient and adaptable framework for energy-efficient and economical edge computing.

Optics↗
DOE OSTI2023

GEM detectors for the CMS endcap muon system: status of three new detector stations

The High-Luminosity LHC (HL-LHC, or Phase-2 LHC) will deliver proton-proton collisions at 5–7.5 times the nominal LHC luminosity, with an expected number of 140–200 pp-interactions per bunch crossing (Pile-up or PU). To maintain the performance of muon triggering and reconstruction under high background, the forward part of the Muon Spectrometer of the CMS experiment will be upgraded with Gas Electron Multipliers (GEM) and improved Resistive Plate Chambers (iRPC) detectors. A first GEM station (GE1/1) was installed during Long Shutdown 2 (LS2, 2019–2021), a 2 nd station (GE2/1) of Triple-GEM detectors will be installed in winter 2023–24 and 2024–25, while a new 6-layer station (ME0) will be installed in the third Long Shutdown (LS3, 2026–2028). GE11 is considered an early Phase-2 upgrade as it will reduce the p T threshold by combining GEM and Cathode Strip Chamber (CSC) hits in the forward muon system at twice the LHC design luminosity ($\mathcal{L}$ = 2 · 10 34 cm -2 s -1 , 50 PU). After a successful start of Run-3 in 2022, with almost 40 fb -1 collected, the commissioning of the GE1/1 detector is nearly complete. Most chambers are operated stably with an efficiency in excess of 95%, next being the demonstration of the combined CSC-GEM trigger in 2023. The lessons learnt with the first large-area GEM station have lead to improvements in detector and electronics design for the Phase 2 detectors GE2/1 and ME0. This proceeding will discuss the progress made since last MPGD Conference (MPGD 2019), discussing the commissioning and early performance of GE1/1; the design improvements and start of construction of GE2/1; and the R&D currently ongoing for ME0.

47 OTHER INSTRUMENTATION↗
DOE OSTI2026

Investigating the Role of Polymer Architecture in Poly(methyl methacrylate) Depolymerization

Advanced architectures in polymers have garnered traction within the last two decades due to their distinct and tunable properties compared to linear analogs. However, the effects of architecture on nascent polymethacrylate depolymerization strategies remain underexplored. Herein, we investigate the depolymerization behavior of poly(methacrylate)-based star copolymers synthesized via a core-first approach. By incorporating either labile chain-end or pendent-group triggers, we demonstrate the first direct comparison of bulk depolymerization behaviors in star versus linear methacrylate copolymers under matched conditions. While pendent-triggered systems required higher loadings of N-(methacryloxy)phthalimide methacrylate (PhthMA) to achieve similar mass loss compared to linear copolymers, chain-end-initiated depolymerization showed enhanced efficiency of monomer liberation in the star topology. Furthermore, these findings highlight the importance of considering macromolecular architecture in designing sustainable polymers and provide actionable guidelines for installing depolymerization triggers based on polymer topology.

Copolymers↗
DOE OSTI2018

Upgrade of the ATLAS Thin Gap Chamber Electronics for HL-LHC

The High-Luminosity LHC (HL-LHC) is planned to start its operation in 2026 with an instantaneous luminosity of 7.5×10 34 cm -2 s -1 . Studies with data taken by ATLAS indicate that the upgraded first level trigger with fast tracking for HL-LHC can reduce the rate of a single muon trigger by 25% for the p T threshold of 20 GeV while maintaining similar efficiency. First prototype of the ATLAS Thin Gap Chamber frontend board has been developed with most of the functions required for HL-LHC implemented. Performance of data transfer has been demonstrated with charged particle beams at the CERN SPS beam facility.

Kawaguchi, Tomomi↗
DOE OSTI2018

Evolution of Oxyhalide Crystals under Electron Beam Irradiation: An in Situ Method To Understand the Origin of Structural Instability

The oxyhalides have attracted growing interest because of their excellent photocatalytic performance. However, their structural instability hampers further development toward practical applications, a major challenge of current concerns. It is appealing to figure out the origin of structural instability and guide the design of advanced oxyhalide crystals for efficient photocatalysis. In this study, the decomposition of BiOCl crystals, a typical oxyhalide, is triggered by electron beam irradiation and investigated in situ by transmission electron microscopy. The results indicate that the instability originates from the unique layered structure of BiOCl crystals; the interlayer van der Waals bonds are easily broken under electron beam irradiation via the assistance of hydroxyl groups. This facilitates the formation of O/Cl-deficient BiO 1–x Cl 1–y species, Bi metal nanoparticles, and nanobubbles (gaseous substance) that are confined between the adjacent layers. Surface reconstruction would be an effective way to stabilize the oxyhalide crystals.

36 MATERIALS SCIENCE↗
DOE OSTI2024

CO2 response screen in grass Brachypodium reveals the key role of a MAP kinase in CO2-triggered stomatal closure

Abstract Plants respond to increased CO2 concentrations through stomatal closure, which can contribute to increased water use efficiency. Grasses display faster stomatal responses than eudicots due to dumbbell-shaped guard cells flanked by subsidiary cells working in opposition. However, forward genetic screening for stomatal CO2 signal transduction mutants in grasses has yet to be reported. The grass model Brachypodium distachyon is closely related to agronomically important cereal crops, sharing largely collinear genomes. To gain insights into CO2 control mechanisms of stomatal movements in grasses, we developed an unbiased forward genetic screen with an EMS-mutagenized B. distachyon M5 generation population using infrared imaging to identify plants with altered leaf temperatures at elevated CO2. Among isolated mutants, a “chill1” mutant exhibited cooler leaf temperatures than wild-type Bd21-3 parent control plants after exposure to increased CO2. chill1 plants showed strongly impaired high CO2-induced stomatal closure despite retaining a robust abscisic acid-induced stomatal closing response. Through bulked segregant whole-genome sequencing analyses followed by analyses of further backcrossed F4 generation plants and generation and characterization of sodium azide and CRISPR-cas9 mutants, chill1 was mapped to a protein kinase, Mitogen-Activated Protein Kinase 5 (BdMPK5). The chill1 mutation impaired BdMPK5 protein-mediated CO2/HCO3− sensing together with the High Temperature 1 (HT1) Raf-like kinase in vitro. Furthermore, AlphaFold2-directed structural modeling predicted that the identified BdMPK5-D90N chill1 mutant residue is located at the interface of BdMPK5 with the BdHT1 Raf-like kinase. BdMPK5 is a key signaling component that mediates CO2-induced stomatal movements and is proposed to function as a component of the primary CO2 sensor in grasses.

Lopez, Bryn N. K. (ORCID:0009000937288216)↗
DOE OSTI2025

Particle Acceleration in Collisionless Magnetically Arrested Disks

We present the first collisionless realization of two-dimensional axisymmetric black hole accretion consistent with a persistent magnetically arrested disk state. The accretion flow, consisting of an ion-electron disk plasma combined with magnetospheric pair creation effects, is simulated using first-principles general-relativistic particle-in-cell methods. The simulation is evolved over significant dynamical timescales during which a quasisteady accretion state is reached with several magnetic flux eruption cycles. We include a realistic treatment of inverse Compton scattering and pair production, which allows for studying the interaction between the collisionless accretion flow and pair-loaded jet. Our findings indicate that magnetic flux eruptions associated with equatorial magnetic reconnection within the black hole magnetosphere and the formation of spark gaps are locations of maximal particle acceleration. Flux eruptions, starting near the central black hole, can trigger Kelvin-Helmholtz-like vortices at the jet-disk interface that facilitate efficient mixing between disk and jet plasma in this region. Transient periods of increased pair production following magnetic flux eruptions and reconnection events are responsible for most of the highly accelerated particles.

Accretion disk & black-hole plasma↗
DOE OSTI2023

CHEETAH: Compact High Efficiency Electrically Tunable Amplifier (Abbreviated Final Report)

The goal of this project was to develop a new type of optically triggered, high speed and high power switch for radiofrequency applications with potential to exceed current state-of-the-art power and bandwidth. This device operates under a new operation principle, where discrete packets of charge carriers are generated with defined size. These are then swept out of the device at high enough fields to prevent diffusion and expansion of these packets. Individual pulse width are determined by the spatial extent of these packets and their drift velocity, which would enable control over both amplitude and frequency by control of the initial packet size, illumination intensity, and applied voltage. This effort demonstrated this new mode of operation, while uncovering a new regime of pulse compression using negative differential mobility (NDM) semiconductors such as GaAs, where the output electrical pulse is substantially shorter than the input optical pulse.

42 ENGINEERING↗
DOE OSTI2018

Mu2e Calorimeter Clustering Studies [Slides]

aMu2e (muon-to-electron-conversion), an Intensity Frontier experiment at Fermilab set to begin data taking in 2022, will search for flavor violation in charged leptons with a muon decaying to only an electron without any neutrinos. Protons will be accelerated by the 8GeV proton beam before reaching Mu2e’s production target. From there, pions enter an S-shaped Transport Solenoid and travel through a series of absorbers and collimators to select low-energy negatively charged muons from pion decay that will hit the stopping target. Downstream from the stopping target are a curved straw tracker and two annular disk crystal calorimeters. The signal will be a mono-energetic e- with an energy close to the rest mass of a muon. The Mu2e expected single event sensitivity is 2.87e-17. The complimentary trigger strategy will take advantage of both online track searches from the tracker and calorimeter reconstruction. The trigger requires a rejection factor greater than 100 and m ust make its decision within a 3ms time budget. In order to provide high efficiency on signal events, our calorimeter clustering algorithms must be accurate and meet the timing performance. I will discuss the expected performance of two clustering algorithms: a fast algorithm to be used at the trigger level and a more accurate clustering algorithm to be used in the offline reconstruction. The fast algorithm defines clusters by only selecting crystals adjacent to a high energy crystal seed. The full-blown algorithm can find smaller clusters separated from the main cluster, within a distance and timing window, and combine them into one cluster. We have analyzed the topology of the reconstructed clusters by the two algorithms on events with only a conversion electron and combined signal and background events. The goal of these studies is to improve the performance of the fast algorithm to better reconstruct the cluster energy and work within the strict timing budget.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗