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All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

WE-A-17A-07: Evaluation of a Grid-Based Boltzmann Solver for Nuclear Medicine Voxel-Based Dose Calculations

Purpose: Grid-based Boltzmann solvers (GBBS) have been successfully implemented in radiation oncology clinics as dose calculations for e×ternal photon beams and 192Ir sealed-source brachytherapy. We report on the evaluation of a GBBS for nuclear medicine vo×el-based absorbed doses. Methods: Vo×el-S-values were calculated for monoenergetic betas and photons (1, 0.1, 0.01 MeV), 90Y, and 131I for 3 mm vo×el sizes using Monte Carlo (DOS×YZnrc) and GBBS (Attila 8.1-beta5, Transpire). The source distribution was uniform throughout a single vo×el. The material was an infinite 1.04 g/cc soft tissue slab. To e×plore convergence properties of the GBBS 3 tetrahedral meshes, 3 energy group structures, 3 different square Chebyschev-Legendre quadrature set orders (Sn), and 4×2013;7 spherical harmonic e×pansion terms (Pn) were investigated for a total of 168 discretizations per source. The mesh, energy group, and quadrature sets are 8×, 3×, and 16×, respectively, finer than the corresponding coarse discretization. GBBS cross sections were generated with full electronphoton-coupling using the vendors e×tended CEP×S code. For accuracy, percent differences (%Δ) in source vo×el absorbed doses between MC and GBBS are reported for the coarsest and finest discretization. For convergence, ratios of the two finest discretization solutions are reported along each variable. Results: For 1 MeV, 0.1 MeV, 0.01 MeV, Y90, and I-131 beta sources the %Δ in the source vo×el for (coarsest,finest) discretization were (+2.0,−6.4), (−8.0, −7.5), (−13.8, −13.4), (+0.9,−5.5), and (− 10.1,−9.0) respectively. The corresponding %Δ for photons were (+33.7,−7.1), (−9.4, −9.8), (−17.4, −15.2), and (−1.7,−7.7), respectively. For betas, the convergence ratio of mesh, energy, Sn, and Pn ranged from 0.991–1.000. For gammas, the convergence ratio of mesh, Sn, and Pn ranged from 0.998–1.003 while the ratio for energy ranged from 0.964–1.001. Conclusions: GBBS is promising for nuclear medicine vo×el-based dose calculations. Ongoing work includes evaluating GBBS in bone, lung, and realistic clinical PET/SPECT-based activity distributions. Research reported in this publication was supported by the National Cancer Institute of the National Institutes of Health under Award Number R01CA138986. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2014

SU-C-16A-07: Sculpting Isodose Lines: Design of An Internally Shielded Tandem for Cervical Cancer Brachytherapy

Purpose: With the prescription method moving from point A to 3D volume based in cervical cancer HDR brachytherapy, the traditional pear-shaped isodose lines are desired to be sculptured to conform to the irregular shaped target. The standard single channel tandem cannot generate asymmetric isodose lines. Most of the directionally shielded sources proposed in literature are challenging to manufacture and operate. In this study, we proposed a novel internally shielded tandem applicator design which gave users more freedom to manipulate isodose lines while planning. Methods: The proposed tandem design has one centrally located lead cylindrical rod of 8 mm in diameter serving as the internal shield. Multiple source channels with the diameter of 2 mm are evenly spaced and engraved on the central cylindrical rod. The overall diameter of the tandem with polymer encapsulation was kept to be 10 mm. Various number of channels and engraving depths have been tested in the design process. Geant4 Monte Carlo toolkit was used for dose calculation assuming a Varian VS2000 source was placed inside the applicator. A Monte Carlo based planning system has been developed in-house to generate brachytherapy plans. Test plans by using this internally shielded tandem were generated for 3 clinical cases. Results: Water phantom results shown the dose distribution from a VS2000 source in the tandem was strongly distorted towards one direction due to the presence of shielding material. Conformal plans with asymmetric isodose distributions around the tandem can be generated by optimizing dwell times in different channels. Conclusion: An effective and easy-to-use internally shielded tandem was developed. It gave user the freedom to sculpt isodose lines to generate conformal plans for cervical cancer brachytherapy.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2015

TU-G-BRD-02: Automated Systematic Quality Assurance Program for Radiation Oncology Information System Upgrades

Purpose: To: (1) describe an independent, automated, systematic software-based protocol for verifying clinical data accuracy/integrity for mitigation of data corruption/loss risks following radiation oncology information system (ROIS) upgrades; and (2) report on application of this approach in an academic/community practice environment. Methods: We propose a robust approach to perform quality assurance on the ROIS after an upgrade, targeting four data sources: (1) ROIS relational database; (2) ROIS DICOM interface; (3) ROIS treatment machine data configuration; and (4) ROIS-generated clinical reports. We investigated the database schema for differences between pre-/post-upgrade states. Paired DICOM data streams for the same object (such as RT-Plan/Treatment Record) were compared between pre-/post-upgrade states for data corruption. We examined machine configuration and related commissioning data files for changes and corruption. ROIS-generated treatment appointment and treatment parameter reports were compared to ensure patient encounter and treatment plan accuracy. This protocol was supplemented by an end-to-end clinical workflow test to verify essential ROI functionality and integrity of components interfaced during patient care chain of activities. We describe the implementation of this protocol during a Varian ARIA system upgrade at our clinic. Results: We verified 1,638 data tables with 2.4 billion data records. For 222 under-treatment patients, 605 DICOM RT plans and 13,480 DICOM treatment records retrieved from the ROIS DICOM interface were compared, with no differences in fractions, doses delivered, or treatment parameters. We identified 82 new data tables and 78 amended/deleted tables consistent with the upgrade. Reports for 5,073 patient encounters over a 2-week horizon were compared and were identical to those before the upgrade. Content in 12,237 xml machine files was compared, with no differences identified. Conclusion: An independent QA/validation approach for ROIS upgrades was developed and implemented at our clinic. The success of this approach ensures a robust QA of ROIS upgrades without manual paper/electronic checks and associated intensive labor.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

Lambda-scheme spectroscopy in the cat-state field

We investigate the spectroscopical scheme of a three-level system in a Λ-configuration utilizing resonant optical field being a superposition of two Glauber coherent states. The source of the field is explicitly included into the theoretical model. In the limit of strong non-classical field we propose an ansatz for solution of the master equation and calculate the steady-state density matrix. The work of both classical and nonclassical field in the steady-state regime was calculated. It was found that the presence of non-classical field creates strong atom-field correlations that results in absence of dark resonances.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2016

Ultrahigh charging of dust grains by the beam−plasma method for creating a compact neutron source

Generation of high-voltage high-current electron beams in a low-pressure (P = 0.1–1 Torr) gas discharge is studied experimentally as a function of the discharge voltage and the sort and pressure of the plasma-forming gas. The density of the plasma formed by a high-current electron beam is measured. Experiments on ultrahigh charging of targets exposed to a pulsed electron beam with an energy of up to 25 keV, an electron current density of higher than 1 A/cm{sup 2}, a pulse duration of up to 1 μs, and a repetition rate of up to 1 kHz are described. A numerical model of ultrahigh charging of dust grains exposed to a high-energy electron beam is developed. The formation of high-energy positive ions in the field of negatively charged plane and spherical targets is calculated. The calculations performed for a pulse-periodic mode demonstrate the possibility of achieving neutron yields of higher than 10{sup 6} s{sup –1} cm{sup –2} in the case of a plane target and about 10{sup 9} s{sup –1} in the case of 10{sup 3} spherical targets, each with a radius of 250 μm.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2025

Analysis Background & Noise in Stretched Wire Alignment Technique Measurements

The Stretched-Wire Alignment Technique (SWAT) is one method of magnet alignment for linear induction accelerators. The applications of SWAT have been implemented for aligning solenoid magnets on the Scorpius linear induction accelerator which will be sited at the Nevada National Security Site and the Flash X-Ray (FXR) linear induction accelerator at Lawrence Livermore National Laboratory’s Contained Firing Facility. This article describes both systematic (repeatable) and random sources of background and noise as well as practical ways to eliminate or reduce them to acceptable levels. Systematic sources include reflections from wire ends, rapid sag due to ohmic heating of the wire, magnetic materials, and shot rate. Random sources include air currents, vibration of nearby equipment, mechanical stability of test equipment, and the instruments used to measure the wire motion. Mitigations include curve fitting and adaptive noise signal cancellation, and mechanical damping. Finite Element Analysis (FEA) was used to identify and resolve a repeatable wire vibration frequency interfering with the signal resolution. Two stretched wire alignment technique set ups from Sandia National Labs and Lawrence Livermore National Lab have shown background noise sources and ways of mitigating them by either analysis methods or change of mechanical configuration. Conclusions that were drawn included the severe sensitivity of the deflection to even small external interferences of the SWAT wire such that it requires attention to detail in mechanical set up and analysis.

Linear Inductive Accelerator↗
DOE OSTI2019

Circumglobal Response to Prescribed Soil Moisture over North America

A series of idealized prescribed soil moisture experiments is performed with the atmosphere/land stand-alone configuration of the Community Earth System Model, version 1, in an effort to find sources of predictability for high-impact stationary wave anomalies observed in recent boreal summers. We arbitrarily prescribe soil water to have a zero value at selected domains in the continental United States and run 100-member ensembles to examine the monthly and seasonal mean response. Contrary to the lack of a substantial response in the boreal winter, the summertime circulation response is robust, consistent, and circumglobal. While the stationary wave response over the North America and North Atlantic sectors can be well explained by the reaction of a linear dynamical system to heating anomalies caused by the imposed dry land surface, nonlinear processes involving synoptic eddies play a crucial role in forming the remote response in Eurasia and the North Pacific Ocean. A number of other possible factors contributing to the circulation responses are also discussed. Overall, the experiments suggest that, in the boreal summer, soil moisture may contribute to the predictability of high-impact stationary wave events, which can impact regions that are great distances from these source regions.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

Scalable waveguide design for three-level operation in Neodymium doped fiber laser

We have constructed a double clad neodymium doped fiber laser operating on the three-level 4 F 3/2 → 4 I 9/2 transition. The laser has produced 11.5 W at 925 nm with 55% slope efficiency when pumped at 808 nm, comparable to the best previous results for a double-clad fiber configuration on this transition. Higher power pumping with both 808 nm and 880 nm sources resulted in an output of 27 W, albeit at lower slope efficiency. In both cases, output power was limited by available pump, indicating the potential for further power scaling. To suppress the stronger four-level 4 F 3/2 → 4 I 11/2 transition we developed a waveguide that provides spectral filtering distributed along the length of the fiber, based on an all-solid micro-structured optical fiber design, with resonant inclusions creating a leakage path to the cladding. Furthermore, the waveguide supports large mode areas and provides strong suppression at selectable wavelength bands, thus easing the restrictions on core and cladding sizes that limited power scaling of previous approaches.

42 ENGINEERING↗
DOE OSTI2021

Seascape Interface Control Document (V.1)

This paper serves as the Interface Control Document (ICD) for the Seascape automated test harness developed at Sandia National Laboratories. The primary purposes of the Seascape system are: (1) provide a place for accruing large, curated, labeled data sets useful for developing and evaluating detection and classification algorithms (including, but not limited to, supervised machine learning applications) (2) provide an automated structure for specifying, running and generating reports on algorithm performance. Seascape uses GitLab, Nexus, Solr, and Banana, open source codes, together with code written in the Python language, to automatically provision and configure computational nodes, queue up jobs to accomplish algorithms test runs against the stored data sets, gather the results and generate reports which are then stored in the Nexus artifact server.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2021

Seascape Interface Control Document (V. 2)

This paper serves as the Interface Control Document (ICD) for the Seascape automated test harness developed at Sandia National Laboratories. The primary purposes of the Seascape system are: (1) provide a place for accruing large, curated, labeled data sets useful for developing and evaluating detection and classification algorithms (including, but not limited to, supervised machine learning applications) (2) provide an automated structure for specifying, running and generating reports on algorithm performance. Seascape uses GitLab, Nexus, Solr, and Banana, open source codes, together with code written in the Python language, to automatically provision and configure computational nodes, queue up jobs to accomplish algorithms test runs against the stored data sets, gather the results and generate reports which are then stored in the Nexus artifact server.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2022

Seascape Interface Control Document

This paper serves as the Interface Control Document (ICD) for the Seascape automated test harness developed at Sandia National Laboratories. The primary purposes of the Seascape system are: (1) provide a place for accruing large, curated, labeled data sets useful for developing and evaluating detection and classification algorithms (including, but not limited to, supervised machine learning applications) (2) provide an automated structure for specifying, running and generating reports on algorithm performance. Seascape uses GitLab, Nexus, Solr, and Banana, open source software, together with code written in the Python language, to automatically provision and configure computational nodes, queue up jobs to accomplish algorithms test runs against the stored data sets, gather the results and generate reports which are then stored in the Nexus artifact server.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2025

Sextupole reduction via chaos suppression at NSLS-II

We revisit the nonlinear lattice design approach for the National Synchrotron Light Source II (NSLS-II) storage ring. By suppressing chaos, we identify alternative sextupole configurations to the original design, which relied on the conventional approach of simultaneously minimizing Resonance Driving Terms (RDTs) and Amplitude-Dependent Detuning (ADD). These alternatives achieve comparable performance while requiring fewer sextupoles. A detailed comparison of two representative solutions is presented and supported by experimental validation. Our results indicate that dynamic aperture correlates more strongly with global chaos than with individual RDTs, and that the importance of minimizing ADD may have been overstated in earlier design approach.

43 PARTICLE ACCELERATORS↗
DOE OSTI2016

Shift Validation Plan for CASL

This document outlines the benchmarks that will be used for Shift validation for CASL. This plan is divided into five main types of problems, with each building upon the previous: small criticality benchmark problems, including small reactor configurations and critical assemblies; full-core reactor benchmarks for light water reactors; fixed source coupled neutron-photon dosimetry benchmarks; depletion/burnup benchmarks ranging from small pincell problems to full-core reactor depletion; and full-core reactor performance benchmarks. Some of these benchmarks have measured data for comparison and some only have simulated Monte Carlo radiation transport code results for comparison. Upon completion of this validation plan, we will have confidence in Shift to provide reference results for CASL benchmarking.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2025

Benchmarking a Defeatured Geant4 NIF Model with HTOAD and HNED Neutron Data

This study benchmarks a simplified Geant4 NIF Target Chamber (TC) model against foil measurements in two instruments: the HTOAD and HNED Snout. The number of product atoms per source neutron per gram ( N 0 /n/g ) is compared across multiple locations and material configurations. The model reproduces high energy threshold reactions dominated by 14 MeV neutrons to within a few percent, depending on location. Discrepancies occur where scattering and moderation are significant for low energy threshold reactions. The defeatured Geant4 model achieves comparable statistical precision with ∼400 times less CPU time than a full fidelity TC model in MCNP. The results can be produced locally on a laptop without the need for high performance computing. Low energy biasing can be improved by preserving room return pathways and implementing IRDFF cross section evaluations.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2023

Particulate from Lignite Coal Combustion and Impact on Carbon Capture Aerosol Emissions

Conference presentation for 47th International Technical Conference on Clean Energy (Clearwater Clean Energy Conference), Clearwater, Florida, July 23–27, 2023. While aerosol formation is recognized as a leading cause of amine losses and degradation from postcombustion CO 2 capture systems, the factors that can lead to aerosol formation vary widely depending on fuel type, plant configuration, and operating conditions. All of these factors require measurement to fully characterize potential sources of aerosol-based amine losses and should be considered prior to implementing full-scale amine-based CO 2 capture.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2024

An Ultra-Compact X-ray Regenerative Amplifier Free-Electron Laser

There is a growing interest in designing and building compact X-ray Free Electron Lasers (FELs) for scientific and industry applications. In this paper, we report an X-ray Regenerative Amplifier FEL (XRAFEL) design based on a proposed Ultra Compact X-ray FEL configuration. Our results show that an XRAFEL can dramatically enhance the temporal coherence and increase the spectral brightness of the radiation in the hard X-ray regime without increasing the footprint of the FEL configuration. The proposed compact, fully coherent, and high-flux hard X-ray source holds promise as a valuable candidate for a wide range of high-impact applications in both academia and industry.

Singleton, Madison↗
DOE OSTI2016

INTERACTION OF TWO FILAMENT CHANNELS OF DIFFERENT CHIRALITIES

We present observations of the interactions between the two filament channels of different chiralities and associated dynamics that occurred during 2014 April 18–20. While two flux ropes of different helicity with parallel axial magnetic fields can only undergo a bounce interaction when they are brought together, the observations at first glance show that the heated plasma is moving from one filament channel to the other. The SDO /AIA 171 Å observations and the potential-field source-surface magnetic field extrapolation reveal the presence of a fan-spine magnetic configuration over the filament channels with a null point located above them. Three different events of filament activations, partial eruptions, and associated filament channel interactions have been observed. The activation initiated in one filament channel seems to propagate along the neighboring filament channel. We believe that the activation and partial eruption of the filaments brings the field lines of flux ropes containing them closer to the null point and triggers the magnetic reconnection between them and the fan-spine magnetic configuration. As a result, the hot plasma moves along the outer spine line toward the remote point. Utilizing the present observations, for the first time we have discussed how two different-chirality filament channels can interact and show interrelation.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1969

Operations and facilities - DSN operations

Deep Space Stations configured as phase sensitive interferometer to measure apparent change in angular separation between radio sources near time of occultation by sun

Source record↗