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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.

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At least 523 records · Page 29
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Search for Neutrino-Induced Neutral Current Delta Radiative Decay in MicroBooNE and a First Test of the MiniBooNE Low Energy Excess Under a Single Photon Hypothesis (submitted to PRL)

We report results from a search for neutrino-induced neutral current (NC) resonant Δ(1232) baryon production followed by Δ radiative decay, with a h0.8i GeV neutrino beam. Data corresponding to MicroBooNE’s first three years of operations (6.80×10 20 protons on target) are used to select single-photon events with one or zero protons and without charged leptons in the final state (1γ1p and 1γ0p, respectively). The background is constrained via an in-situ high-purity measurement of NC π 0 events, made possible via dedicated 2γ1p and 2γ0p selections. A total of 16 and 153 events are observed for the 1γ1p and 1γ0p selections, respectively, compared to a constrained background prediction of 20.5 ± 3.65(sys.) and 145.1 ± 13.8(sys.) events. The data lead to a bound on an anomalous enhancement of the normalization of NC Δ radiative decay of less than 2.3 times the predicted nominal rate for this process at the 90% confidence level (CL). The measurement disfavors a candidate photon interpretation of the MiniBooNE low-energy excess as a factor of 3.18 times the nominal NC Δ radiative decay rate at the 94.8% CL, in favor of the nominal prediction, and represents a greater than 50-fold improvement over the world’s best limit on single-photon production in NC interactions in the sub-GeV neutrino energy range.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2022

Measurement of neutral current single π 0 production on argon with the MicroBooNE detector

We report the first measurement of π 0 production in neutral current (NC) interactions on argon with average neutrino energy of ≲1 GeV. We use data from the MicroBooNE detector’s 85-tonne active volume liquid argon time projection chamber situated in Fermilab’s Booster Neutrino Beam and exposed to 5.89 × 10 20 protons on target for this measurement. Measurements of NC π 0 events are reported for two exclusive event topologies without charged pions. Those include a topology with two photons from the decay of the π 0 and one proton and a topology with two photons and zero protons. Flux-averaged cross-sections for each exclusive topology and for their semi-inclusive combination are extracted (efficiency-correcting for two-plus proton final states), and the results are compared to predictions from the GENIE, NEUT, and NUWRO neutrino event generators. We measure cross sections of 1.243 ± 0.185 (syst) ±0.076 (stat), 0.444 ± 0.098 ± 0.047, and 0.624 ± 0.131 ± 0.075 [10 -38 cm 2 /Ar] for the semi-inclusive NCπ 0 , exclusive NCπ 0 +1p, and exclusive NCπ 0 +0p processes, respectively.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

Progress Towards an Investigation of the MiniBooNE Low Energy Excess Using Neutral-Current Delta-Like Single Photons in MicroBooNE with Wire-Cell 3D Reconstruction Algorithms

This note presents progress towards a Neutral-Current (NC) Delta-like single photon search in MicroBooNE using Wire-Cell 3D reconstruction and pattern recognition algorithms. This analysis will help address the question of the MiniBooNE Low Energy Excess (LEE) [1]. The selections are similar to the previously published Pandora-based single photon selections [2] in many ways, but here we use independent reconstruction and selection tools and examine a larger phase space (including charged pions and multiple protons). In the future, we will significantly reduce systematic uncertainties via the use of constraining sideband observations in order to statistically test specific models of the MiniBooNE LEE.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

Search for Anomalous Neutral Current Coherent-Like Single-Photon Production in MicroBooNE

MicroBooNE is a liquid argon time projection chamber (TPC) detector which offers excellent spatial and energy resolution and the ability to distinguish electrons from photons. In this note we present preliminary results from a dedicated search for neutral current (NC) single-photon production, with a focus on forward-going photons and no visible hadronic activity, both of which are key characteristics of “coherent-like” electromagnetic shower production. A total efficiency for SM-predicted NC coherent 1$\gamma$ events of 12.5% is obtained, defined relative to simulated events in the entire MicroBooNE active TPC. Relative to the Pandora-reconstructed single-shower event selection, the analysis achieves a 95% rejection of non-coherent NC 1π 0 background events and a 99.97% rejection of cosmic background events, while maintaining a signal efficiency of approximately 45%.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Search for anomalous neutral current coherent-like single-photon production in MicroBooNE

This note describes progress towards the first experimental search for neutrino-induced neutral current coherent single-photon production (NC coherent 1γ). The search makes use of data from the MicroBooNE’s 85-tonne active mass liquid argon time projection chamber detector, situated in Fermilab’s Booster Neutrino Beam, with an average neutrino energy of $\langle$E ν $\rangle$ ~ 0.8 GeV. A selection targeted on candidate neutrino interactions with a single photon-like electromagnetic shower in the final state and no visible vertex activity was developed to search for this rare NC coherent 1γ process.

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

Progress Towards an Expanded Search for Neutral-Current Delta Radiative Decays in MicroBooNE

In this note, we present progress toward an expanded search for neutral current Delta radiative decays (NC $\Delta \rightarrow N\gamma$) in MicroBooNE. We present sensitivities for several tests of the MiniBooNE Low Energy Excess (LEE) under NC $\Delta \rightarrow N\gamma$ scaling hypotheses, with significantly enhanced sensitivity relative to previous tests. These selections can also be used for additional single photon searches in the future, including searches which target more specific hadronic final states and particular regions of shower kinematic phase space.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Search for anomalous neutral current coherent-like single-photon production in MicroBooNE

MicroBooNE is a liquid argon time projection chamber (TPC) detector which offers excellent spatial and energy resolution and the ability to distinguish electrons from photons. In this note we present preliminary results from a dedicated search for neutral current (NC) single-photon production, with a focus on forward-going photons and no visible hadronic activity, both of which are key characteristics of “coherent-like” electromagnetic shower production. A total efficiency for SM-predicted NC coherent 1γ events of 12.5% is obtained, defined relative to simulated events in the entire MicroBooNE active TPC. Relative to the Pandora-reconstructed single-shower event selection, the analysis achieves a 95% rejection of non-coherent NC 1π 0 background events and a 99.97% rejection of cosmic background events, while maintaining a signal efficiency of approximately 45%.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

Progress towards an investigation of the MiniBooNE Low Energy Excess using neutral-current Delta-like single photons in MicroBooNE with Wire-Cell 3D reconstruction algorithms

This note presents progress towards a Neutral-Current (NC) Delta-like single photon search in MicroBooNE using Wire-Cell 3D reconstruction and pattern recognition algorithms. This analysis will help address the question of the MiniBooNE Low Energy Excess (LEE). The selections are similar to the previously published Pandora-based single photon selections in many ways, but here we use independent reconstruction and selection tools and examine a larger phase space (including charged pions and multiple protons). In the future, we will significantly reduce systematic uncertainties via the use of constraining sideband observations in order to statistically test specific models of the MiniBooNE LEE.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Searches for Heavy Neutral Leptons (HNL) in CMS

The smallness of neutrino masses in conjunction with the observed flavor oscillations in the neutrino sector can be hinting to physics beyond the standard model. These observations can be naturally accommodated by the so-called "seesaw" mechanism, in which new Heavy Neutral Leptons (HNL) are postulated. Additionally, several HNL models provide a DM candidate or include a possible explanation for the observed baryon asymmetry. This talk presents an comprehensive overview of the CMS HNL program with a focus on the new experimental results as shown in a recently published review paper by CMS.The talk will highlight several novel and complementary approaches using both prompt and long-lived signatures using the full Run-II data-set collected at the LHC.

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

Technology-Neutral, Accident Containment-Based Path to Reduce Nuclear Power Costs

Cost remains a substantial impediment to nuclear power plant (NPP) deployment. The origin of the multifold cost difference between NPPs and other industrial facilities is in their unique potential for societally disruptive accidents. Consequently, one means to substantially reduce NPP costs would be to provide a transparent means of demonstrating that a plant’s potential for land-contamination accidents is so remote to amount to a practical certainty that no significant quantity of radionuclides would ever reach the public. The necessary confidence can be developed through employing a containment capable of withstanding both a complete internal energy release accident along with credible external events with ample margin. This paper provides an overview of a path forward to develop a technology-neutral, containment-based safety-adequacy demonstration method.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2025

Parylene-N Coatings of Thin Foils for the Mitigation of Neutral Contaminant Desorption and Plasma Formation

Previous experiments utilizing the planar MITL foil platform (T.J. Smith et al. RSI 2021) on the 1-MA, 100-ns Mykonos facility have shown neutral atomic and molecular hydrogen in the gap after rapid heating of the foil surfaces before breakdown. Additionally, previous attempts at using parylene-N as a coating for power flow surfaces on the 1-MA, 100-ns Zebra facility have shown tamping of the electrothermal instability at thicknesses of 50-60 μm (T.M. Hutchinson et al. Phys. Rev. E 2018).

36 MATERIALS SCIENCE↗
DOE OSTI2025

Reinventing wastewater treatment plants: energy neutral treatment and enhanced fertilizer production through a novel resource recovery center

Wastewater treatment plants (WWTPs) are typically energy intensive, mainly due to the secondary treatment processes such as activated sludge (AS) for treatment of organics as well as nutrients like nitrogen. Nitrogen removal presents a big problem for WWTPs. The main form of nitrogen in wastewater is ammonium, and an AS process uses oxygen to convert ammonium into nitrite and nitrate which is then converted to nitrogen through denitrification process. During anaerobic digestion (AD), organic nitrogen gets degraded, resulting in an effluent stream (centrate) with a high nitrogen content, mostly in the form of ammonium. This contributes 15-30% of total nitrogen to the wastewater influent which further increases energy consumption for aeration. The project aims to transform this conventional municipal WWTPs into energy-neutral, resource-recovering facilities by integrating three core technologies: • Cloth Media Filtration (CMF) to replace conventional primary sedimentation (CPS) and increase the diversion of organics from the energy intensive secondary treatment to AD. This results in reduced energy demand for aeration in the secondary process while simultaneously increasing the biogas production in the anaerobic digesters. • Anerobic Digester to increase biogas and ammonia production. • Membrane Evaporation (ME) to recover ammonia from AD centrate and produce marketable fertilizer. The benefits of proposed WWTP process modifications were evaluated using techno economic analysis (TEA) and life cycle assessment (LCA). For CMF portion of the research a statistical analysis was employed to develop data-driven tools that could be used to enhance and optimize its performance in terms of energy savings and effluent quality. The main objective of this project is to reduce the energy demand for secondary treatment at municipal WWTPs by at least 50%, increase anaerobic digester (AD) biogas and ammonia production by 100% and 120%, respectively, and recover 90% of ammonia from the AD. Integrated CMF, AD, and ME was shown to work synergistically toward achieving these decarbonization targets through energy-positive treatment and fertilizer recovery techniques.

42 ENGINEERING↗
DOE OSTI2026

Neutral beams for the burning plasma era: Simulations and modeling of deuterium ion beams for plasma heating (CRADA Final Report)

Together with Realta Fusion, we set up several simulation scenarios and ran simulations using the WarpX code which is developed by LBNL and especially by members of the LBNL team. We investigated beam transport and beam neutralization and ran optimization and benchmark simulations. To achieve this, several new features were added to the warpX code. These code additions will also be beneficial to other users of warpX including several fusion companies and researchers at National Laboratories. Furthermore, we supported Realta Fusion in setting up their own instances of WarpX. We presented our results at the American Physical Society Division of Plasma Physics meeting and are in the process of writing a publication that will be submitted to a peer-reviewed journal to share our results with the broader community.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2026

Towards searches for heavy neutral leptons with the Short-Baseline Near Detector experiment

Heavy Neutral Leptons (HNLs) are hypothetical long-lived particles that extend the Standard Model and provide a natural explanation for the origin of neutrino masses, the generation of the baryon asymmetry through leptogenesis, and the nature of dark matter. The Short-Baseline Near Detector (SBND) is a 112-ton liquid argon time projection chamber located 110 m away from the Booster Neutrino Beam (BNB) target at Fermilab (Illinois, USA). The close location to the BNB origin makes the experiment sensitive to HNLs produced from meson decays in the beam. These heavy particles arrive at the detector later than neutrinos and decay into observable final states such as 𝜈e+e- or 𝜈π0, generating isolated electromagnetic showers. Thanks to SBND’s advanced scintillation light detection system, a timing resolution at the nanosecond level further boosts the experiment capabilities. In this poster, we present ongoing reconstruction efforts towards HNLs as well as expected sensitivities factoring in the reconstruction improvements.

Romeo Araujo, Jorge [Madrid, CIEMAT]↗
DOE OSTI2026

Near Detector Selection for Neutral Current Disappearance Search at the Short-Baseline Neutrino Program

Various short baseline neutrino experiments observe anomalies that challenge the three-flavor neutrino oscillation model, consistent with a hypothetical “sterile” neutrino that does not interact via the weak force. This poster presents a near detector event selection at the Short-Baseline Near Detector (SBND), developed for the first search for neutral current (NC) disappearance at short-baseline experiments. NC disappearance provides ``smoking gun” insight into the sterile neutrino question because NC interactions are equally sensitive to all three active neutrinos, meaning any change in the NC interaction rate between near and far detectors cannot be explained by oscillations among known flavor states. This analysis focuses on the NC1p topology, the most common NC interaction type at the Short-Baseline Neutrino (SBN) Program. NC topologies are inherently challenging due to their low light yield and the absence of an outgoing charged lepton, which complicates identification and leads to poor energy reconstruction as the outgoing neutrino carries away a large portion of the neutrino’s initial energy. This work presents an NC1p event selection at the near detector, highlighting SBND’s impressive detector capabilities, including trigger efficiency studies. Combined with a novel kinematic energy reconstruction technique leveraging the detector’s outstanding hadronic detail, this analysis establishes a robust near detector foundation to target an NC disappearance measurement consistent with the 3$+$1 sterile neutrino model. This SBND selection will soon be combined with the far detector to conduct an NC disappearance search, providing unique insight and complementary information to traditional charged current searches and advancing the SBN Program’s goal to resolve the sterile neutrino question, including 3$+$1 searches and beyond.

Nicole Pallat, Nicole Pallat [Minnesota U.] (ORCID↗
DOE OSTI2026

A Vertical GaN-Based Neutral-Pointless Three-Level Inverter for High-Performance Automotive Traction Applications

Silicon Carbide (SiC) MOSFETs have emerged as a dominant solution for electric vehicle traction inverters because of their superior power density and efficiency compared to Silicon (Si) counterparts. However, SiC devices possess inherent switching speed limitations that constrain the maximum switching frequency and hinder further power density and efficiency improvements. To address these limitations, this paper proposes a vertical Gallium Nitride (vGaN) based X-type Neutral-Pointless (NPL.X) three-level (3L) inverter for an 800V, 200 kW traction system. Integrating 700V vGaN technology within the NPL.X 3L topology enables improved drive efficiency and higher switching frequencies, resulting in enhanced power density and output power quality. To evaluate the performance benefits, this work conducts a comprehensive loss characterization of the vGaN￾based NPL.X topology, providing a direct comparison with a SiC￾based two level (2L) inverter. The results show that the proposed vGaN-based inverter achieves superior efficiency, particularly within the low-torque regions that dominate standard automotive drive cycles. The proposed vGaN-based inverter represents a critical advancement toward high-power-density and high efficiency traction drives

Halawa, Ali [Purdue Univ., West Lafayette, IN (Uni↗