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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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Ionizing-radiation beam monitoring system

A transmissive ionizing-radiation beam monitoring system includes an enclosure structure with at least one ultra-thin window to an incident ionizing-radiation beam, where the ultra-thin window is highly transmissive to ionizing-radiation. Embodiments include at least one thin or ultra-thin scintillator within the enclosure structure that is substantially directly in an incident ionizing-radiation beam path and transmissive to the incident radiation beam, and at least one ultraviolet (UV) illumination source within the enclosure structure facing the scintillator. Embodiments include at least one machine vision camera within the enclosure structure located out of an incident ionizing-radiation beam path and including a camera body and lens having a projection of its optical axis oriented at an angle of incidence of 45±35 degrees to a surface of the scintillator.

Friedman, Peter S.↗
DOE OSTI2021

Ionizing-radiation beam monitoring system

Embodiments are directed generally to an ionizing-radiation beam monitoring system that includes an enclosure structure with at least one ultra-thin window to an incident ionizing-radiation beam. Embodiments further include at least one scintillator within the enclosure structure that is substantially directly in an incident ionizing-radiation beam path and at least one ultraviolet illumination source within the enclosure structure and facing the scintillator. At least one pixelated imaging system within the enclosure structure is located out of an incident ionizing-radiation beam path and includes at least one pixelated photosensor device optically coupled to an imaging lens.

Friedman, Peter S.↗
DOE OSTI2025

Phase transition in two-dimensional monolayer (1L)-molybdenum disulfide induced by atomic S-basal plane gliding via synchrotron X-ray monochromatic beam radiation for superior electronic performance

Here, in this work, we report a novel approach to reduce the channel resistance by inducing a phase transition behavior from 2H to 1T in a monolayer MoS 2 (1L-MoS 2 ) by a synchrotron X-ray monochromatic beam (mono-beam) radiation. The effects of the biphase structure by the mono-beam on the 1L-MoS2 film were investigated using Raman spectra, photoluminescence (PL) spectra, scanning tunneling microscopy, and scanning tunneling spectroscopy, respectively. Through material characterization, we identified that the lateral sliding of S-vacancies along the S-plane in the 1L-MoS 2 is the key reason for the origin of unidirectional phase transition. The precise phase engineering triggered by the mono-beam radiation process allows the realization of field-effect transistors (FET) with 2X improvement in mobility toward a high on/off ratio (~10 8 ) and a near-ideal subthreshold swing of ~88 mV per decade. The validity of the phase engineering could be further extended for its application as a memory device, exhibiting a gate tunable conduction modulation behavior and a high resistance ratio of ~10 2 at a gate bias of 5 V with endurance of ~100 cycles. Furthermore, an artificial neural network using the synaptic weight update with accuracy of ~93 % was achieved.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Impact of High-Dose-Rate and Low-Dose-Rate Brachytherapy Boost on Toxicity, Functional and Cancer Outcomes in Patients Receiving External Beam Radiation Therapy for Prostate Cancer: A National Population-Based Study

External beam radiation therapy (EBRT) with brachytherapy boost reduces cancer recurrence in patients with prostate cancer compared with EBRT monotherapy. However, randomized controlled trials or large-scale observational studies have not compared brachytherapy boost types directly.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
NASA NTRS1997

Multilayer Analyses of an Iron Radiation Beam Experiment

A nonperturbative analytic solution of Green's function for heavy ion transport in a single medium is extended to multilayer transport media. This extension is implemented in the Green's function code (GRNTRN), which is being validated with laboratory experiments. Good agreement is achieved between an iron radiation beam experiment and GRNTRN only when the interactions of the iron radiation beam with several important layers of material located upstream of the target within the beamline are considered.

Shinn, J. L.↗
DOE OSTI2021

Intraoperative Electron Beam Radiation Therapy (IOERT) Versus High-Dose-Rate Intraoperative Brachytherapy (HDR-IORT) in Patients With an R1 Resection for Locally Advanced or Locally Recurrent Rectal Cancer

Intraoperative radiation therapy (IORT), delivered by intraoperative electron beam radiation therapy (IOERT) or high-dose-rate intraoperative brachytherapy (HDR-IORT), may reduce the local recurrence rate in patients with locally advanced and locally recurrent rectal cancer (LARC and LRRC, respectively). The aim of this study was to compare the oncological outcomes between both IORT modalities in patients with LARC or LRRC who underwent a microscopic irradical (R1) resection.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2022

Dose Summation Strategies for External Beam Radiation Therapy and Brachytherapy in Gynecologic Malignancy: A Review from the NRG Oncology and NCTN Medical Physics Subcommittees

Definitive, nonsurgical management of gynecologic malignancies involves external beam radiation therapy (EBRT) and/or brachytherapy (BT). Summation of the cumulative dose is critical to assess the total biologic effective dose to targets and organs at risk. Cumulative dose calculation from EBRT and BT can be performed with or without image registration (IR) and biologic dose summation. Among these dose summation strategies, linear addition of dose-volume histogram (DVH) parameters without IR is the global standard for composite dose reporting. This approach stems from an era without image guidance and simple external beam and brachytherapy treatment approaches. With technological advances, EBRT and high-dose-rate BT have evolved to allow for volume-based treatment planning and delivery. Modern conformal therapeutic radiation involves volumetric or intensity modulated EBRT, capable of simultaneously treating multiple targets at different specified dose levels. Therefore, given the complexity of modern radiation treatment, the linear addition of DVH parameters from EBRT and high-dose-rate BT is challenging to represent the combined dose distribution. Deformable image registration (DIR) between EBRT and image guided brachytherapy (IGBT) data sets may provide a more nuanced calculation of multimodal dose accumulation. However, DIR is still nascent in this regard, and needs further development for accuracy and efficiency for clinical use. Biologic dose summation can combine physical dose maps from EBRT and each IGBT fraction, thereby generating a composite DVH from the biologic effective dose. However, accurate radiobiologic parameters are tissue-dependent and not well characterized. A combination of voxel-based DIR and biologic weighted dose maps may be the best approximation of dose accumulation but remains invalidated. The purpose of this report is to review dose summation strategies for EBRT and BT, including conventional equivalent dose in 2-Gy fractions dose summation without image registration, physical dose summation using 3-dimensional rigid IR and DIR, and biologic dose summation. We also provide general clinical workflows for IGBT with a focus on cervical cancer.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
NASA NTRS2023

Statistical Study of the Non-Thermal Continuum Radiation Beaming Angle Measured By the High Frequency Receiver on Van Allen Probes-A

The nonthermal continuum (NTC) radiation beaming angle is computed over the entire Van Allen Probes-A mission when the spacecraft was in the dawn sector. The conditions in the dawn sector are favorable for the wave vector to lie near/in the spacecraft's spin plane allowing a favorable estimate of the beaming angle, and the dawn sector is also advantageous in that previous studies show NTC occurrence to peak in this sector. We found that scatter plots, over the entire mission, of beaming angle versus magnetic latitude form a distinct inverted-V pattern, with the apex at/near the magnetic equator. This pattern was sharpest for frequencies (f) ≲ 100 kHz. Using the NTC beaming formula from the linear mode conversion theory (LMCT), we show that such an inverted-V pattern is expected due to the large variation in the plasmapause location over the entire mission. The theoretical derived pattern qualitatively reproduces the observed pattern but not quantitatively. The lack of quantitative agreement is discussed and is attributed to several factors, one factor is off-centered emissions from the radio window. The qualitative agreement strongly supports LMCT as being the dominant mechanism generating NTC for f ≲ 100 kHz. For f ≳ 100 kHz, the inverted-V pattern becomes less distinct, and strong near-equatorial beaming is observed. After considering contamination of our selections by left-handed polarized AKR, our study suggests that besides LMCT another unidentified NTC generation mechanism becomes important for f ≳ 100 kHz.

Linear Mode Conversion Theory↗
DOE OSTI2023

Statistical Study of the Nonthermal Continuum Radiation Beaming Angle Measured by the High Frequency Receiver on Van Allen Probes-A

The nonthermal continuum (NTC) radiation beaming angle is computed over the entire Van Allen Probes-A mission when the spacecraft was in the dawn sector. The conditions in the dawn sector are favorable for the wave vector to lie near/in the spacecraft's spin plane allowing a favorable estimate of the beaming angle, and the dawn sector is also advantageous in that previous studies show NTC occurrence to peak in this sector. We found that scatter plots, over the entire mission, of beaming angle versus magnetic latitude form a distinct inverted-V pattern, with the apex at/near the magnetic equator. This pattern was sharpest for frequencies ( f ) ≲ 100 kHz. Using the NTC beaming formula from the linear mode conversion theory (LMCT), we show that such an inverted-V pattern is expected due to the large variation in the plasmapause location over the entire mission. The theoretical derived pattern qualitatively reproduces the observed pattern but not quantitatively. The lack of quantitative agreement is discussed and is attributed to several factors, one factor is off-centered emissions from the radio window. The qualitative agreement strongly supports LMCT as being the dominant mechanism generating NTC for f ≲ 100 kHz. For f ≳ 100 kHz, the inverted-V pattern becomes less distinct, and strong near-equatorial beaming is observed. Finally, after considering contamination of our selections by left-handed polarized AKR, our study suggests that besides LMCT another unidentified NTC generation mechanism becomes important for f ≳ 100 kHz.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1975

Payload dose rate from direct beam radiation and exhaust gas fission products

A study was made to determine the dose rate at the payload position in the NERVA System (1) due to direct beam radiation and (2) due to the possible effect of fission products contained in the exhaust gases for various amounts of hydrogen propellant in the tank. Results indicate that the gamma radiation is more significant than the neutron flux. Under different assumptions the gamma contribution from the exhaust gases was 10 to 25 percent of total gamma flux.

Capo, M. A.↗
DOE OSTI2021

Actinic and electron beam radiation curable water based electrode binders and electrodes incorporating same

A process for manufacturing an electrode utilizing electron beam (EB) or actinic radiation to cure the electrode binder is provided. A process is also disclosed for mixing specific actinic or EB radiation curable polymer precursors with electrode solid particles to form an aqueous mixture, application of the mixture to an electrode current collector, followed by the application of actinic or EB radiation to the current collector for curing the polymer, thereby binding the electrode binder to the current collector. Lithium ion batteries, electric double layer capacitors, and components produced therefrom are also provided.

Voelker, Gary E.↗