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DOE OSTI2024

Alaska Hydrogen Opportunities Report

This inaugural report on Alaska's hydrogen energy opportunities introduces key themes for developing a hydrogen economy in Alaska, establishes a baseline understanding of Alaska's infrastructure and resources relevant to hydrogen, and contextualizes this baseline in terms of national and global initiatives focused on hydrogen. This report could be further developed into a hydrogen roadmap or a statewide hydrogen strategy in the future. The driving group behind this report, the Alaska Hydrogen Working Group, was formed in 2022 to address the increasing interest in hydrogen energy opportunities in Alaska. As of December 2023, there were nearly 200 members representing industry, government, academia, communities, tribal entities, and interested citizens from both inside and outside Alaska. Since its inception, the group has met monthly to discuss issues of interest and to share insights and questions. One task is to synthesize Alaska's hydrogen energy opportunities and potential into a report. This task not only reflects grassroots interest but also responds to objectives outlined in Alaska Statewide: Comprehensive Economic Development Strategy 2022-2027 (Alaska Department of Commerce, Community, and Economic Development, 2022), one of which is to develop and implement a hydrogen roadmap for Alaska. The goals of this report are to enhance knowledge and information sharing, spur innovation and investment that could help transform Alaska's energy systems, and identify economic and workforce development opportunities across the state. Following the elements of the hydrogen economy outlined in the U.S. National Clean Hydrogen Strategy and Roadmap, published in June 2023, this report explores the production, storage/delivery, and end-use options in evolving markets for Alaska, both within and outside the state. It also outlines key opportunities to identify and develop infrastructure investments, policy and regulatory frameworks, future research and demonstration priorities, economic and investment considerations, and workforce programs. These goals and opportunities are intended to support a statewide hydrogen energy economy that is equitable, diverse, environmentally just, and supportive of Indigenous rights and value systems.

08 HYDROGEN↗
DOE OSTI2022

ORNL Neutron Cross Section Measurements of 90 Zr NCSP ND-1 Task [Slides]

Luiz Leal's idea to integrate the experimental uncertainties, covariances, and sensitivities in the ND workflow and to centralize the process at one location created a cohesive tool for data testing. It has been practiced for more than two decades by the NCS and ND groups at ORNL. The development and use of the ORNL codes TSUNAMI and TSURFER within SCALE made it possible. Today, it has been extended to SAMINT, which enables the coupling of differential and integral data evaluation in a continuous-energy framework.

43 PARTICLE ACCELERATORS↗
DOE OSTI2019

First-principles Studies of Tritium Reactivity and Diffusivity on Defective and Carbon Doped Surfaces of $\gamma$-LiAlO 2 Pellets (Tritium Science Program Report FY 2019 )

In tritium-producing burnable absorber rods (TPBARs), tritium ($^{3}_{1}$H,T) is produced in 6 Li isotope enriched γ-LiAlO 2 ceramic pellet. However, a better understanding of $^{3}_{1}$H transport through the pellets, getters and the barrier/cladding system is hampered by a lack of fundamental data about the $^{3}_{1}$H solubility and diffusivity. In the process of $^{3}_{1}$H diffusion from bulk γ-LiAlO 2 to its surface, it is possible that $^{3}_{1}$H atoms bind with surface atoms or become trapped at vacancies sites. By increasing the number of $^{3}_{1}$H diffused from bulk to surface, upon recombination and desorption from surface sites, they will escape from the γ-LiAlO 2 surface to form different $^{3}_{1}$H species (possibly being as T, T 2 , T 2 O, OT, or CT x (x=1-4, with C impurity present at a 100-600 ppm level in pellets) that need to be identified and can become captured by the getter. Therefore, exploring the $^{3}_{1}$H diffusion from bulk to surface, corroborated with surface adsorption, diffusion and recombination and followed by desorption from surface as various types of $^{3}_{1}$H species becomes a very important task as an integral part of the study of $^{3}_{1}$H solubility and diffusivity in the pellets.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2019

Manufacturing and Reliability Science for CIGS Photovoltaics

The purpose of this program was to overcome the largest challenges to investor confidence and long product lifetime in CuIn x Ga 1-x Se 2 (CIGS)-based photovoltaic products: metastability, shading-induced hot spots, and potential-induced degradation. Key findings were made in each of these areas by studying CIGS reliability at the cell level, which very few groups are currently doing. Metastability was thought to be a function of the CIGS absorber. We have challenged the state-of-the-art by showing that the metastability seen in commercial products is likely to be caused by the buffer layer. SCAPS device modeling confirmed that the buffer layer has a significant influence on metastability in CIGS devices, and also led to a processing change - the introduction of CdS islands to Zn(O,S) buffer layers - that dramatically reduced metastability in CIGS solar cells. In the reverse-bias shading task, modeling showed us that 19% solar cells are possible with thin CIGS layers of 0.5 µm. We were able to fabricate 15.2% solar cells in this project, which is the highest reported efficiency of devices in the ultra-thin class. We also discovered that the best way to dissipate less power in reverse bias was to eliminate the intrinsic ZnO layer that is often used in CIGS devices. Lower power dissipation led to devices that allowed two times the maximum power point current density in reverse without damage. Potential-induced degradation (PID) is caused by the drift of Na+ ions from the back glass to the CIGS/Mo interface, followed by diffusion into the solar cells and to the CdS region. We found that PID can be slowed by using low-conductivity borosilicate glass that contains higher K and lower Na than soda-lime glass. Based on significant progress in each of the three reliability challenges, the CIGS cell-level reliability project was very successful. We have also proved that module-level degradation mechanisms can be tested and solved at the cell level.

14 SOLAR ENERGY↗
DOE OSTI2017

Composition-directed Fe X Mo 2-X P bimetallic catalysts for hydrodeoxygenation reactions

The development of task-specific bimetallic phosphide catalysts can be accomplished by exploiting the electronic and bi-functional effects of multiple metal combinations, thus providing materials with tunable catalytic properties. Here, we present the modulation of metal compositions (i.e., Fe and Mo) in the synthesis of FeXMo 2-X P (0.88 ≤ X ≤ 1.55), leading to a series of iso-structural, orthorhombic Fe X Mo2-XP catalysts via reduction at 750 °C. Hydrodeoxygenation of phenol was selected as a probe reaction to showcase the effect of metal composition on the catalytic performance. In particular, catalysts with Fe compositions between 0.99 and 1.14 (i.e., Fe0. 99 Mo 1.01 P and Fe 1.14 Mo 0.86 P) exhibited high selectivities to C–O bond cleavage of phenol with H2 to form benzene. The catalysts with the highest selectivities to C–O scission also exhibited the highest acidity as determined from NH 3 temperature programmed desorption experiments. Density functional theory (DFT) calculations indicate the high Lewis acidity for the ~1:1 Fe:Mo compositions resulted from a greater charge separation between metallic species and P species. These compositions led to greater selectivities to benzene due to desired coordination environment of the phenol on catalytic surface, as evidenced by both DFT calculations and a time on stream study using a benzonitrile poison. Enhanced TOFs were also observed with catalysts exhibiting greater Lewis acid character, which reduce the activation energy required to cleave the C–O bond of phenol, as evidenced by DFT calculations. This structure–property study highlights the effects of metal composition in bimetallic phosphides to enhance the activity and selectivity for C–O bond cleavage reactions.

Rensel, Dallas J.↗
DOE OSTI2020

Radiation Simulation using Wi-Fi Signal Strength and Frequency

For routine radiological operations, lost radioactive sources, decommissioning and cleanup of nuclear facilities, and radiological terrorist events such as Radioactive Dispersive Devices (RDDs) or Radiological Exposure Devices (REDs), individuals are tasked with accurately locating both point and distributed sources of radiation. Radiation workers must often practice these tasks, whether part of initial training or periodically as part of formal or informal exercises or drills. In such circumstances, it is desirable to have an accurate recreation of a radioactive source, including a method of detecting it, which does not include dangerous amounts of radiation. The goal of this research was to develop a radiation simulation technology that uses IEEE 802.11x W-LAN protocol, i.e. Wi-Fi sources and detectors for these, as an inexpensive, precise and accurate method of replicating sources of gamma radiation. For this work, existing 802.11x sources were used. Software was developed for use with an Android smartphone to detect the presence of these sources. The measurements followed the expected behavior as a function of distance from the sources, mimicking that of gamma radiation, thus demonstrating the fundamental principle of operation. The ultimate system will be used in an outreach program to interest students in the radiation protection field.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2018

Lessons Learned from a Laser Injury Event - Limitations of Skill-Of-The-Craft

A technician at INL received 2nd degree burns to the middle and ring fingers of his left hand while performing a preventive maintenance (PM) procedure on a Class 4 industrial laser on August 30, 2011. The task required placement of a “target” in the beam path to verify mirror alignment. The technician, believing the laser was in a safe mode, reached into the beam pathway to place the target, saw a flash and immediately withdrew his hand. Three INL technicians were assigned to perform a 2000 hour run time PM on a laser. A pre-job briefing was held August 29, 2011 by the acting foreman and the technicians started the PM. They had completed 25 steps in Section I of the work order by the end of the day. The laser systems were placed under LO/TO and the internal optics were cleaned and/or replaced. The LO/TO was released and the next morning, August 30, 2011, the technicians prepared to take a diagnostic shot inside the internal optics. The laser was powered up at the HMI, and the person in charge (PIC) selected the “Mirror Alignment” program from the human machine interface (HMI) screen, enabled the pendent and pressed the “Cycle Start” button. The technicians believed the laser was in “simmer” mode at this point and that no beam was being generated out of the resonator. A beam was being generated in the “Mirror Alignment” program when the “Cycle Start” button was pressed. They decided to check the #4 aperture target and see if they were aligned at that location. One of the technicians reach to place the target at the end of the Z box and a “Flash” occurred. The technician immediately retracted his hand with the target. The PIC turned off the high voltage (HV) at the pendent. The foreman and supervisor were informed of the incident and the injured technician was escorted to an onsite medical facility. The nurse evaluated the injury and sent the technician to a physician for further evaluation. A physician examined the technician’s hand. The technician’s left middle and ring fingers received 2nd degree burns to both finger tips. A prescription burn ointment and bandage was applied. The employee was returned to work with no restrictions.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2025

Optimizing Alabama’s CO 2 Storage in Shelby County (Project OASIS) - Deliverable Task 7: Risk Assessment

The “Optimizing Alabama’s CO 2 Storage in Shelby County: Project OASIS” CarbonSAFE Phase II Project seeks to build on regional data sets that demonstrate that the subsurface within Shelby County, Alabama has the potential to store commercial volumes of CO 2 safely, permanently, and economically. The primary target CO 2 Storage Complex is the deep Ketona Dolomite located within a 140 square mile area of the Valley and Ridge Region of Alabama. This deep saline reservoir is beneath a confining system encompassing at least 6,500 ft of shales and other low permeability sediments. Project OASIS drilled a deep stratigraphic test well to confirm the geological properties of the confining system and storage reservoir(s) within the Storage Complex. The geological data was incorporated into numerical models to establish the areal extent of the CO 2 plume and help design the storage site and its monitoring system. The project is managed by the Southern States Energy Board (SSEB), an interstate compact organization consisting of governors and state legislative leaders from sixteen southern states, Puerto Rico, and the U.S. Virgin Islands, as well as an appointee by the President of the United States. The organizational compact provides it with access to state government organizations and legislatures. The Board also maintains an Associate Members program comprised of energy resource companies, utilities, trade groups, academic R&D science and technology experts and energy consultants. Further, the SSEB staff is experienced in managing and coordinating complex energy and environmental programs, from research programs to full-scale design and demonstrations of new and innovative technologies. Project OASIS is a public-private partnership of six entities with multiple principal investigators (PIs). SSEB’s Lead PI and Co-PI are responsible for all aspects of project performance in accordance with the DOE-NETL Cooperative Agreement. SSEB has issued subgrants to Advanced Resources International, Inc., Alabama A&M University, Auburn University, Crescent Resource Innovation, and Oklahoma State University. Advanced Resources International, Inc., issued subgrants to Baker Hughes and Loudon Technical Services for field services

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2023

Enhancing Monte Carlo Workflows for Nuclear Reactor Analysis with Metamodel-Driven Modeling

Monte Carlo codes are essential components of many reactor physics simulation workflows as high-fidelity continuous-energy neutron transport solvers. Among Monte Carlo radiation transport codes, MCNP is particularly notable due to its diverse simulation capabilities, large user base, and long validation history. Despite being a powerful simulation tool, MCNP provides limited capabilities to allow automated execution, model transformation, or support for user-defined logic and abstractions that limit its compatibility with modern workflows. Here, to better integrate MCNP into a modern scientific workflow, we have developed an intuitive yet full-featured MCNP Application Program Interface (API) in Python, named MCNPy, which provides a specialized set of classes for MCNP input development. Moreover, to guarantee that our reading, writing, and modeling capabilities remain self-consistent (and to render the huge scope of the MCNP API manageable), we have adopted a strategy of model-driven software development in which a generalized model of the MCNP input format has been created. From this generalized model, or “metamodel,” problem-specific implementations such as an engine for input validation or a codebase for programmatic operations may be automatically generated. Since MCNPy primarily acts as a Python front-end to the underlying Java API that directly interfaces with the metamodel, it is intrinsically linked to the metamodel and thus remains maintainable. With MCNPy, users can programmatically read, write, and modify any syntactically valid MCNP input file regardless of its origin. These capabilities allow users to automate complicated tasks like design optimization and model translation for nuclear systems. As examples, this work demonstrates the use of MCNPy to find the critical radius of a plutonium sphere and to translate a 9000+ line MCNP input file into a corresponding OpenMC model.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2019

Highlights and Lessons Learned from Army Re-tuning™ Pilot Demonstrations

The Army has aggressively pursued policy and energy efficiency projects and programs in recent years to meet Federal mandates and reduction goals organizationally (EISA 2007, AR 420-1, 42 U.S.C. § 8253), resulting in a 9.6% reduction in energy use intensity (EUI) from FY2015 to FY2017. Despite these successes, the Army remains the largest consumer of electricity in the Federal government and spent approximately $1.1 billion in energy-related costs in FY2017. Many of the low-cost/no-cost conservation measures have been deployed, so finding additional savings and projects that either (a) are cost effective or (b) can be bundled with more costly capital improvement projects to improve life cycle cost effectiveness, is imperative for the Army. Leveraging building control systems (BCS) and optimizing building performance through re-tuning represents a great opportunity for the Army. In 2016, the Pacific Northwest National Laboratory (PNNL), in support of the Assistant Secretary of the Army (Installations, Energy and Environment), i.e. ASA (IEE), was tasked in 2016 with a multi-year study and pilot demonstration to develop a business case for the potential energy and cost reduction benefits from re-tuning efforts for the Army.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2017

Streamlining and Transparently Automating Complex Waste Determinations at Los Alamos National Laboratory - 17286

Environmental programs at Los Alamos National Laboratory (LANL) generate a large amount of sampling activities that can result in waste that needs to be characterized and properly disposed. Since 2011, sampling results are managed in the cloud-based Environmental Information Management (EIM) database, which contains over 16 million current and historical data records. In many cases, the database's analytical records are used to characterize and dispose waste from environmental operations. Three factors contribute to streamlining of the waste disposition operations: (1) if possible, use of the existing analytical data for waste characterization to avoid additional laboratory analysis; (2) reduction in time spent on data evaluation for various waste acceptance criteria; and (3) choice of the proper and least expensive disposal alternative. Use of the existing analytical data, when allowed by law, creates some paradoxical problems: when chemical analysis is requested with the purpose of characterizing waste, it creates only 100 to 400 analytical records. However, use of exiting analytical data at LANL may lead to evaluation of tens of thousands of analytical records, with many records for each single analyte. This occurs because data were collected for environmental characterization and not waste characterization. To streamline data analysis for waste disposition using existing data, LANL has created a Waste Data Summary (WDS) module in the site's EIM database. Recognizing that waste determination is performed by groups outside the environmental program at LANL, the WDS allows for logically guided data selection for a specific waste determination (solids, liquids, radiological, etc.) and reduces potentially thousands of rows of data into simple formatted data reports that are easy to comprehend and process. This allows the waste evaluators to review data using multiple approaches to make their own determination on the most appropriate disposal method. There are four basic principles of WDS operation: (1) The highest detected analytical result is evaluated for the selected samples (or the lowest undetected result if there are no detected results); (2) All approved disposal pathways are evaluated; (3) Any failures of the Waste Acceptance Criteria are visibly highlighted to focus the attention of the evaluator; and (4) The decision of the disposal path is left to the trained waste evaluator (WDS does not choose or suggest any disposal paths). The summary results are presented as the set of short data reports. These reports can be divided into two groups: general comparison reports and disposal pathway specific forms. The general comparison forms show all Resource Conservation and Recovery Act (RCRA) analytes with pass/fail evaluation and with preference for toxicity characteristic leaching procedure (TCLP) results (or 20x rule) for solid samples, the potential RCRA hazard codes assignment for detected analytes, and all rad results. The detected chemical and radioactivity results are compared to the background values and to Soil Screening and Soil Action limits (SSL/SAL limits). Disposal pathway specific forms follow Waste Acceptance Criteria requirements for all disposal pathways available at LANL. The programming of the WDS tries to maximize existing data by analyte substitutions (like using gross alpha for necessary alpha emitting isotopes) or by making calculations when analytical results do not agree with legal requirements (like total chlordane in the RCRA regulations, which is most often analyzed and reported as individual isomers). All forms may be annotated by the waste evaluator to provide additional information to support decision making. Upon final decision of a disposal path, the complete dataset used in the evaluation and the WDS forms with annotations is 'frozen' as an un-editable PDF export to document the data used in the waste disposal determination. The streamlined process results in less work for waste evaluators and reduces overall labor and analytical costs. By comparison, a full review of a 10,000 record parent dataset may take a waste evaluator over a week to review, whereas with the WDS module, the task can be accomplished in less than one hour with clear, reproducible results. These results can be reviewed and checked at any time by quality assurance personnel, thus ensuring transparency in the decision making process. LANL believes this approach has broad applicability to other sites where waste determination is based on review of existing data collected for more generalized environmental purposes. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2024

Advanced Shuttle Strategies for Parallel QCCD Architectures

Trapped ions (TIs) are at the forefront of quantum computing implementation, offering unparalleled coherence, fidelity, and connectivity. However, the scalability of TI systems is hampered by the limited capacity of individual ion traps, necessitating intricate ion shuttling for advanced computational tasks. The quantum charge-coupled device (QCCD) framework has emerged as a promising solution, facilitating ion mobility for universal quantum computation. Current QCCD architectures predominantly feature a linear topology, which is increasingly recognized as inefficient for complex quantum operations. Anticipating the shift toward more efficacious designs, this article introduces an innovative quantum scheduling strategy optimized for parallel QCCD topologies. Our strategy proposes a probabilistic formula for ion movement, alongside ingenious methods for local layer generation and layer compression, yielding a significant reduction in ion shuttle times. Through simulations, we demonstrate that our strategy not only substantially outstrips the linear model but also exhibits better performance over other parallel strategies that employ greedy algorithms. This is achieved through our nuanced resolution of complexities, such as traffic blocks and trap capacity limitations. The consequent reduction in shuttle operations leads to lower energy consumption and an enhancement in the quantum computer's fidelity, ultimately accelerating program execution times.

43 PARTICLE ACCELERATORS↗
DOE OSTI2018

Advanced Ultrasupercritical (AUSC) Materials Thick-Walled Cycling Header Development for ComTest-AUSC (Final Report)

Alstom Power Inc., a wholly owned subsidiary of the General Electric Company (GE) recently completed “Advanced Ultrasupercritical (AUSC) Materials Thick-Walled Cycling Header Development for ComTest-AUSC” under Award No. DE-FE0026183 for the U.S. Department of Energy National Energy Technology Laboratory (DOE NETL). This project developed a design for testing of a high temperature nickel-based superalloy thick-walled header to simulate cycling and flexible plant operation in new and existing plants. The objective was to simulate the expected thermal stresses of a new AUSC plant or a retrofit header in an existing plant to improve flexible dynamic operation while maintaining component integrity and overall power plant reliability. The high performance superalloy materials that enable higher operating temperatures and pressures can support future transformational power technologies including new AUSC plants at 4250-5000 psi, 730°C/760°C or will serve as a replacement component in a repowered or retrofit USC coal powered cycling plant at 3600 psi, 600°C. These alloys can also enable supercritical CO2 cycles, nuclear power, solar power and more efficient natural gas combined cycle units as targeted by the U.S. DOE/NETL Cross-Cutting Research Technology Program Plan. Recently developed advanced nickel alloys such as Inconel 740H (740H) and Haynes 282 (H282) have been successfully tested on a pilot scale for fireside corrosion using steam loop tubing at AUSC temperatures of 760°C in actual operating coal fired boiler. These high strength materials have been demonstrated their adequacy for use in other high temperature boiler components such as superheater tubes. Thick-walled superheater outlet headers which operate at high temperatures and pressure under severe cycling condition are considered as one of the most critical component in the AUSC coal fired boiler. Over the design life of a plant, these headers are exposed to the most severe fatigue and creep damage accumulation and need to be properly designed for the expected cycling in an AUSC plant with flexible operation. These materials need to demonstrate adequate design life of 20 to 30 years for creep and fatigue conditions. The following tasks were performed: 1. A conceptual design was developed of a thick-walled component representative of typical headers with several tube connections and proper flow rates (~100,000 lbs/hr) suitable for Phase II test at 760°C operation. This was based on a process analysis of expected full scale new and component retrofit designs for AUSC; 2. A multi-physics flow and heat transfer computational fluid dynamics (CFD) analysis of the component for proper layout of the header configuration, number and geometry (size) of tubes required for bypass flow, flow rates through the tubing, and sectional pressure drops was performed. Steam to header metal heat transfer film coefficients in the header section and the tubes during the two stages (half load and full load) of the cycling operation were evaluated and used in the stress analysis; 3. Detailed analytical evaluation of the thick-walled pipe and tube connections for mechanical integrity under cycling conditions was performed. This included transient thermal stress analysis and fatigue usage estimation including the tube-to-pipe weld geometries and weld materials; 4. A layout and design of the thick-walled test component was developed and instrumentation required for a test was identified; 5. Continuum Damage Mechanics (CDM) creep prediction models were extended to 740H and H282 and validated with public data on 740H and H282 for use in creep analysis. In addition, detailed creep analyses were performed separately for the design life of the conceptual AUSC superheater outlet header using these General Electric (GE) creep constitutive models. GE was the prime contractor for the project, which was directed by Principal Investigator Robert Schrecengost and Lead Scientist Dr. B. Reddy Ganta. Other collaborative participants in this project included GE Global Research, GE Boiler Engineering, and a Technical Consultant from EPRI.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2020

Counter Unmanned Aircraft System (CUAS) Implementation Storyline

This report is an FY21 Deliverable for NA-21.1, International Nuclear Security, WBS 21.1.1.1.4 Counter Unmanned Aircraft Systems (CUAS), under C.1.4, Develop Suite of Engagement Materials and Tools for Country/Regional Teams. The responsibility for protecting nuclear assets is an immense challenge for governments. Policy changes based on geopolitics, instability of government regimes, and technological advances that facilitate theft of nuclear material all contribute to the enduring task of staying current with these and other threats. One of the recent threats to come along is the use of drones or Unmanned Aircraft Systems (UAS) to circumvent traditional Physical Security Systems. There are significant resources invested on physical protection systems for securing nuclear assets, but many of these systems can now be bypassed by simply flying over these measures intended to guard against ground attacks. In recent years the threat increased to hostile groups to attack or surveil due to advances and availability of UAS platforms. It is now more urgent to implement systems and procedures to counter the UAS threat. The United States (U.S.) federal government granted authority to the Department of Energy (DOE) to implement a Counter UAS to protect nuclear assets. This document provides a very practical and transparent view of the trials, tribulations and challenges we encountered while implementing the first Counter-Unmanned Aircraft System (CUAS) Program in the DOE at Los Alamos National Laboratory (LANL).

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2022

Chlorine Worth Study in Support of PF-4 Operations [Slides]

The primary concern of this study is if experiments can be designed/conducted to provide technical justification to NCS in order to increase mass limits. This goal is in direct support of 30 pits per year mission, one of the top priorities for NNSA. The accelerated timeline is as follows: Initial tasking, June 2020; preliminary design completion (CED-1 equivalent), November 2020; final design completion (CED-2 equivalent), March 2021; part receipt and inspection completion (CED-3a equivalent), October 2021; experiment execution (CED-3b equivalent), December 2021; experiment documentation write-up completion (start CED-4a equivalent), January 2022; and ICSBEP target (CED-4a equivalent), Fall 2022.

2019 ARCHIMEDES LDRD project↗
DOE OSTI2018

Beam asymmetry for photoproduced omega mesons off bound protons in deuterons

Quantum chromodynamics (QCD) is the fundamental theory underlying the strong interaction. Great effort has been dedicated to explain hadron interactions and the hadron composition in terms of the QCD degrees of freedom (quarks and gluons). However, this task has been largely complicated by confinement, an intrinsic feature of QCD itself, which prevents us from a direct experimental study of the dynamics of quarks and gluons. Instead, QCD-inspired models have been developed to explain the hadron spectrum, and while there has been success in explaining important features of it, many of the states that have been predicted by these models have not been found experimentally. Furthermore, the hadronic spectrum is much more complicated to analyze than the atomic one because of a high number of excited states of the nucleon which have large widths that cause resonances to overlap. Also, these resonances may decay into a multitude of decay channels involving either mesons or baryons. Additionally, we will need measurements of observables, coming from polarized beam and polarized target experiments, to obtain a complete measurement of all the helicity amplitudes. My current research aims at contributing to a larger experimental program that seeks to shed light on the evolving status of the proton spectrum. I focus on the photoproduction of ω mesons off the bound proton, which is of great interest in providing information about N* resonances as ω is an isospin filter. I have extracted a preliminary quasi-free right-arrow gamma delta → ωp(n) photon beam asymmetry polarization observable from CLAS data. The ω meson was identified through its charged decay ω → π + π - π 0 where the π 0 subsequently decays in two photons. The data were taken during the E06-103 experiment with the CLAS detector in Hall B at the Thomas Jefferson National Accelerator Laboratory (JLab). The experiment used the Hall-B Coherent Bremsstrahlung Facility to provide a high quality beam of linearly-polarized photons in the energy range from 1.1 to 2.3 GeV.

Source record↗
DOE OSTI2021

Clustering of electromagnetic showers and particle interactions with graph neural networks in liquid argon time projection chambers

Liquid argon time projection chambers (LArTPCs) are a class of detectors that produce high resolution images of charged particles within their sensitive volume. In these images, the clustering of distinct particles into superstructures is of central importance to the current and future neutrino physics program. Electromagnetic (EM) activity typically exhibits spatially detached fragments of varying morphology and orientation that are challenging to efficiently assemble using traditional algorithms. Similarly, particles that are spatially removed from each other in the detector may originate from a common interaction. Graph neural networks (GNNs) were developed in recent years to find correlations between objects embedded in an arbitrary space. The graph particle aggregator (GrapPA) first leverages GNNs to predict the adjacency matrix of EM shower fragments and to identify the origin of showers, i.e., primary fragments. On the PILArNet public LArTPC simulation dataset, the algorithm achieves a shower clustering accuracy characterized by a mean purity of 99.4%, a mean efficiency of 99.6% and a primary identification accuracy of 99.8%. It yields a relative shower energy uncertainty of (4.1 + 1.4 / $\sqrt{\text{E(GeV)})}$% and a shower direction uncertainty of (2.1/ $\sqrt{\text{E(GeV)})}$°. Finally, the optimized algorithm is then applied to the related task of clustering particle instances into interactions and yields a mean purity of 99.8% and a mean efficiency of 99.5% for an interaction density of $\mathcal{O}(1)$ m –3 .

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

Establishing the World Reference for Measuring the Atmospheric Longwave Irradiance with Traceability to the International System of Units

Advancing climate change research requires accurate and traceable measurement of atmospheric longwave irradiance. Measurement capabilities are limited to an estimated uncertainty of larger than +/- 6 W/m2 using the interim World Infrared Standard Group (WISG). Two independently designed and calibrated absolute radiometers measuring downwelling longwave irradiance were compared during five outdoor comparisons in 2013, 2015, and 2017 at the Physikalisch Meteorologisches Observatorium Davos World Radiation Center (PMOD/WRC) and the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement program (ARM) in the Southern Great Planes (SGP). Two Absolute Cavity Pyrgeometers (ACPs) developed by the National Renewable Energy Laboratory (NREL) and four Integrating Sphere Infrared Radiometers (IRISs) developed by PMOD/WRC took part in these intercomparisons.From the five comparisons, the difference between the irradiance measured by ACPs and IRISs varied from 0.2 W/m2 to 2.5 W/m2 based on atmospheric conditions, which is within the combined stated uncertainties of +/- 3 W/m2. The irradiance measured by the WISG is lower than the average irradiance measured by ACPs and IRISs. The magnitude of difference varied from 0.2 W/m2 to 6.6 W/m2 depending on the integrated water vapor. A concerted effort to establish a world reference for measuring the atmospheric longwave irradiance with lower uncertainty and with traceability to the International System of Units (SI) by using the ACPs and IRISs as the reference started at the World Meteorological Organization (WMO). The Commission for Instruments and Methods of Observation Commission (CIMO) Task Team on Radiation References (TT) meeting was held in 2017 at the National Physical Laboratory (NPL), in Teddington, United Kingdom to discuss specific recommendation on the traceability of the atmospheric longwave irradiance to the International System of units (SI).

14 SOLAR ENERGY↗