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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 1,009 records · Page 56
All sourcesNASA NTRSDOE OSTI
NASA NTRS2003

Correlation of Radiation Dosage With Mechanical Properties of Thin Films

The objective of this investigation was to examine the relationship between irradiation level (proton dose), microstructure, and stress levels in chemical vapor deposited diamond and polysilicon film using crosssectioned specimens. However, the emphasis was placed on the diamond specimen because diamond holds much promise for use in advanced technologies. The use of protons allows not only the study of the charged particle that may cause the most microstructural damage in Earth-orbit microelectromechanical systems (MEMS) devices, but also allows the study of relatively deeply buried damage inside the diamond material. Using protons allows these studies without having to resort to megaelectronvolt implant energies that may create extensive damage due to the high energy that is needed for the implantation process. Since 1 MEMS devices operating in space will not have an opportunity to reverse radiation damage via annealing, only nonannealed specimens were investigated. The following three high spatial resolution techniques were used to examine these relationships: (I) Scanning electron microscopy, (2) micro-Raman spectroscopy, and (3) micro x-ray diffraction.

Newton, R. L.↗
NASA NTRS1982

Texas Instruments' virtual phase charge-coupled device (CCD) imager operated in the frontside electron-bombarded mode

The present investigation is concerned with the suitability of the virtual phase CCD imager for frontside detection of electrons up to 25 keV. The investigation has the objective to determine if the imager can be used in the frontside mode with a photocathode to detect very low light levels in astronomical applications, the ultimate goal being individual photon detection. It is found that the standard virtual phase imager will function properly over an extended period at low levels of 20 kV electron irradiation consistent with photon counting applications. The imager can detect individual primary electrons with nearly 100 percent efficiency. However, further studies are needed to determine the mechanisms for the flat band shifts so that the imager design may be modified to eliminate or at least reduce them.

Everett, P.↗
DOE OSTI2025

Beyond Epitaxy: Ion Implantation as a Tool for Orbital Engineering

Manipulating electronic orbital states in quantum materials provides a powerful means of controlling their physical properties and technological functionality. Here, we demonstrate that orbital populations in strongly correlated oxide thin films can be continuously and reversibly tuned through postsynthesis He ion implantation. Using LaNiO 3 as a model system, we show that the orbital preference can be systematically adjusted from favoring in-plane d x 2 –y 2 occupation toward out-of-plane d z 2 states through precise control of ion fluence. Unlike conventional heteroepitaxial approaches that lock in orbital configurations during growth, this strain-doping technique enables continuous orbital tuning and the selective modification of specific film regions after device fabrication. We demonstrate the practical impact of this control by achieving a 7-fold enhancement in oxygen reduction reaction catalysis. This work establishes ion implantation as a powerful approach for orbital engineering that complements existing synthesis-based strategies while offering unique advantages for both basic research and device development.

Doping↗
DOE OSTI2022

Total-Ionizing-Dose Effects on Read Noise of MLC 3-D NAND Memories T

This paper analyzes the total ionizing dose (TID) effects on noise characteristics of commercial multi-level-cell (MLC) 3-D NAND memory technology during the read operation. Additionally, the chips were exposed to a Co-60 gamma-ray source for up to 100 krad(Si) of TID. We find that the number of noisy cells in the irradiated chip increases with TID. Bit-flip noise was more dominant for cells in an erased state during irradiation compared to programmed cells.

3-D NAND Flash↗
DOE OSTI2015

Technical Note: Response measurement for select radiation detectors in magnetic fields

Purpose: Dose response to applied magnetic fields for ion chambers and solid state detectors has been investigated previously for the anticipated use in linear accelerator–magnetic resonance devices. In this investigation, the authors present the measured response of selected radiation detectors when the magnetic field is applied in the same direction as the radiation beam, i.e., a longitudinal magnetic field, to verify previous simulation only data. Methods: The dose response of a PR06C ion chamber, PTW60003 diamond detector, and IBA PFD diode detector is measured in a longitudinal magnetic field. The detectors are irradiated with buildup caps and their long axes either parallel or perpendicular to the incident photon beam. In each case, the magnetic field dose response is reported as the ratio of detector signals with to that without an applied longitudinal magnetic field. The magnetic field dose response for each unique orientation as a function of magnetic field strength was then compared to the previous simulation only studies. Results: The measured dose response of each detector in longitudinal magnetic fields shows no discernable response up to near 0.21 T. This result was expected and matches the previously published simulation only results, showing no appreciable dose response with magnetic field. Conclusions: Low field longitudinal magnetic fields have been shown to have little or no effect on the dose response of the detectors investigated and further lend credibility to previous simulation only studies.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS2006

Electron-Induced Displacement Damage Effects in CCDs

We compare differences in parametric degradation for CCDs irradiated to the same displacement damage dose with 10-MeV and 50-MeV electrons. Charge transfer efficiency degradation was observed to not scale with NIEL for small signals.

Juno Mission↗
NASA NTRS2009

Irradiation with molecular hydrogen as an accelerated total dose hardness assurance test method for bipolar linear circuits

High dose rate irradiation with hydrogen stress is proposed as an accelerated total dose test method for bipolar linear circuits. The method is validated across process and circuit technologies with five parts that are commonly used in space: a comparator (LM193 from National Semi-conductor), a voltage regulator (HSYE-117 RH from Intersil), a voltage reference (LT1019 from Linear Technology), a JFET input op amp (OP42 from Analog Devices) and a temperature transducer (AD590 from Analog Devices). The testing technique could rapidly establish an upper bound to the low dose rate response of parts in space and help with the part selection process in the design phase of a mission. The technology dependence and the viability of this technique are qualitatively explored using a physical model describing the dose rate response and the effect of hydrogen in bipolar technologies. The model uses four core processes: 1) space charge effects, 2) free electron/hole pair recombination, hole-hydrogen defect reactions in the oxides and 4) proton depassivation of dangling bonds at the Si/SiO2 interface. Radiation hardness assurance implications are discussed.

Pease, Ron↗
DOE OSTI2014

Neutron detection using boron gallium nitride semiconductor material

In this study, we developed a new neutron-detection device using a boron gallium nitride (BGaN) semiconductor in which the B atom acts as a neutron converter. BGaN and gallium nitride (GaN) samples were grown by metal organic vapor phase epitaxy, and their radiation detection properties were evaluated. GaN exhibited good sensitivity to α-rays but poor sensitivity to γ-rays. Moreover, we confirmed that electrons were generated in the depletion layer under neutron irradiation. This resulted in a neutron-detection signal after α-rays were generated by the capture of neutrons by the B atoms. These results prove that BGaN is useful as a neutron-detecting semiconductor material.

36 MATERIALS SCIENCE↗
DOE OSTI2022

High-resolution magnetic field fingerprinting of integrated circuit activity with a quantum diamond microscope

Devices for determining a state of a magnetic field-generating article are provided. In various embodiments, a device comprises: a single crystal diamond having a plurality of NV centers, the single crystal diamond configured to be disposed adjacent to a magnetic field-generating article, and configured to generate a fluorescent signal in response to being illuminated by a light source; a coherent light source configured to generate a light beam directed at the single crystal diamond; a microwave (MW) radiation source configured to irradiate the single crystal diamond with a MW signal; a magnetic field source configured to apply a bias magnetic field to the single crystal diamond; a photosensor configured to collect the fluorescent signal generated by the single crystal diamond; and a computing node operatively coupled to each of the coherent light source, the MW radiation source, the magnetic field source, and the photosensor.

Turner, Matthew James↗
DOE OSTI2014

Optical, ferroelectric, and piezoresponse force microscopy studies of pulsed laser deposited Aurivillius Bi₅FeTi₃O₁₅ thin films

Bi₅FeTi₃O₁₅ (BFTO) based Aurivillius ferroelectric thin films were fabricated on strontium ruthanate coated amorphous fused silica substrates using pulsed laser deposition technique. Optical, ferroelectric, and piezoresponse properties of these thin films were investigated. The estimated refractive index (n) and extinction coefficient (k) for these films were in the range from 2.40 to 2.59 and 0.012 to 0.19, respectively. The bandgap of the BFTO thin layers was estimated to be 2.88 eV. Domain switching and hysteresis loops of BFTO films were studied utilizing piezoresponse force microscopy (PFM). The measured apparent polarization (P{sub r}) and coercive field (E{sub c}) for the samples were 20 μC/cm² and 250 kV/cm, respectively. The amplitude and phase hysteresis curves obtained from PFM characterization reveal that these films can be switched below 5 V. These results suggest that BFTO in thin film form is a promising material for photo ferroelectric and optoelectronic devices applications.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2016

MEXIICO: a new equipment to study the pressure impact on the irradiated fuel behavior

The new MEXIICO experimental loop has recently been started in the LECA-STAR hot-cell facility of the CEA Cadarache. It is dedicated to the understanding of the basic mechanisms occurring in nuclear fuels during nuclear reactor power transients and accidental situations. Under such conditions the nuclear fuels are submitted to thermo-mechanical stresses. These stresses play a major role on fission product release and fuel fragmentation. Evaluating such fuel behavior represents a key issue for reactor safety analyses. In the first part of the paper, we describe the complete MEXIICO device, which main component is a hot isostatic press allowing to perform analytical experiments in the [20 -1600 C. degrees / 10 MPa - 160 MPa] region. As shown by simulations (ALCYONE fuel performance code), the upper value of the pressure (160 MPa) is consistent with the one experienced by fuels under nuclear power transients. We also present the experimental loop starting from the argon pressurized feed-line, the furnace and its associated instrumentation and the exhaust line equipped with specific valves and flowmeters controlling the pressure and flowrate. We then focus on the gamma spectrometry measurement which allows recording the fission gas release kinetics. In the second part of the paper, we detail the capability of the MEXIICO device to provide new experimental data regarding the influence of pressure on the fission gas release and fuel fragmentation, and to determine a pressure threshold above which fission gas release and fuel fragmentation may be inhibited. This device also allows investigating the impact of pressure on the microstructure evolution, coupling it with post-test microanalysis examinations: this procedure will allow characterizing the effect of temperature and pressure on the bubble evolution and interconnection. Evolutions of the fuel modeling, needed to simulate correctly these new experimental data, will be also presented. In the last section of the paper, we present the commissioning tests of the MEXIICO device showing the good reproducibility of the tests performed first in conventional laboratory and then in hot-cell laboratory. (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2016

SHI induced damage in electrical properties of silicon NPN BJTs

The investigation of radiation damage in Si microelectronic circuitry and devices are being carried out by various research groups globally. In particular the Si Bipolar junction transistors are very sensitive to high energetic radiation. In the present study, radiation response of NPN Bipolar junction transistor (2N3773) has been examined for 60 MeV B{sup 4+} ion. Key electrical properties like Gummel, dc current gain and capacitance – voltage (C-V) characteristics of 60 MeV B{sup 4+} ion irradiated transistor were studied before and after irradiation. Ion irradiation and subsequent electrical characterizations were performed at room temperature. Current voltage (I-V) measurements showed the increase in collector current for V{sub BE} ≤ 0.4 V as a function of fluence, which is due to B{sup 4+} ion induced surface leakage currents. Base current is observed to be more sensitive than collector current and gain appears to be degraded with ion fluence. Also, C-V measurements shows that both built in potential and doping concentration increased significantly after irradiation.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2014

SU-C-19A-06: A Robust and Affordable Table Indexing Approach for Total Lymphoid Irradiation Treatment

Purpose: Total lymphoid irradiation (TLI) is conventionally delivered through the dosimetric matching of mantle, spleen, and pelvis fields, necessitating multiple isocenters delivered through a combination of couch shifts and sliding of patients relative to the couch rendering the technique susceptible to shifting errors. To address this challenge, a novel technique for the couch indexing of TLI treatments is developed and evaluated through a multi-patient pilot trial. Methods: An immobilization device was designed consisting of a movable indexed slide board with an Exact Lok-Bar drilled into it. A Timo headrests were used fixate the head of the patient relative to the slide board. For the Varian Exact Couch™, the immobilization board was connected to the H3 notch to avoid the metal infrastructure of the couch for the delivery of the mantle and spleen fields. For tall patients the required shift for the pelvis isocenter reaches the shifting limit and the board was slid from H3 to H4 (a fixed distance of 14 cm). A total 22 patients were stratified in two groups of 11, one consisting of the conventional setup, and one group with the proposed immobilization technique. Results: The standard deviations (SD) of the couch positions in lateral, longitudinal, and vertical directions for 10 fractions for each patient in both groups were calculated. In the non-indexed group, the positioning SD ranged from 0.9 to 4.7 cm. Using our device, the positioning SD was reduced to a range of 0.2 to 0.9 cm, with the longitudinal direction showing the largest improvement. Conclusion: Matched field TLI remains error prone to geometrical misses. The feasibility of full indexing TLI treatments was validated and shown to result in a significant reduction of positioning errors.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Bioluminescence Tomography–Guided Radiation Therapy for Preclinical Research

Purpose: In preclinical radiation research, it is challenging to localize soft tissue targets based on cone beam computed tomography (CBCT) guidance. As a more effective method to localize soft tissue targets, we developed an online bioluminescence tomography (BLT) system for small-animal radiation research platform (SARRP). We demonstrated BLT-guided radiation therapy and validated targeting accuracy based on a newly developed reconstruction algorithm. Methods and Materials: The BLT system was designed to dock with the SARRP for image acquisition and to be detached before radiation delivery. A 3-mirror system was devised to reflect the bioluminescence emitted from the subject to a stationary charge-coupled device (CCD) camera. Multispectral BLT and the incomplete variables truncated conjugate gradient method with a permissible region shrinking strategy were used as the optimization scheme to reconstruct bioluminescent source distributions. To validate BLT targeting accuracy, a small cylindrical light source with high CBCT contrast was placed in a phantom and also in the abdomen of a mouse carcass. The center of mass (CoM) of the source was recovered from BLT and used to guide radiation delivery. The accuracy of the BLT-guided targeting was validated with films and compared with the CBCT-guided delivery. In vivo experiments were conducted to demonstrate BLT localization capability for various source geometries. Results: Online BLT was able to recover the CoM of the embedded light source with an average accuracy of 1 mm compared to that with CBCT localization. Differences between BLT- and CBCT-guided irradiation shown on the films were consistent with the source localization revealed in the BLT and CBCT images. In vivo results demonstrated that our BLT system could potentially be applied for multiple targets and tumors. Conclusions: The online BLT/CBCT/SARRP system provides an effective solution for soft tissue targeting, particularly for small, nonpalpable, or orthotopic tumor models.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2025

Imaging Power Losses in CdSeTe Solar Cells

Much of the research on CdSeTe photovoltaics is focused on improving the open-circuit voltage (V oc ) of the solar cell. But solar cells operate at the maximum power point (MPP) rather than at V oc . The recombination processes at MPP may be different than those at V oc , and increasing the power output at MPP is the key to advancing efficiency. Here, we introduce a camera-based PL imaging system that enables power loss analysis under operating conditions and across cm-sized areas covering multiple cells. The instrument is demonstrated with CdSeTe devices having efficiencies greater than 19%. An implied current density versus implied voltage (iJV) curve can be produced at each pixel with <20 µm resolution. We find that regions with high implied open circuit voltage are often those with low implied fill factor, showing that voltage loss analysis at open circuit is not sufficient to understand power losses under operating conditions. Measurement of JV curves as a function of irradiance can also be performed in the system, which allows series resistance-free pseudo JV (pJV) curves to be produced. Comparison of pJV to measured JV and iJV curves allows further analysis of the operational losses, pointing the way to higher efficiency.

14 SOLAR ENERGY↗
DOE OSTI2021

Design, construction, and testing of no-insulation small subscale solenoids for compact tokamaks

Fusion energy systems studies (FESS) for next-step devices based on the most promising magnetic configurations indicate that high magnetic fields and high current density for magnet coil systems may reduce device size and lower the cost. High current density and radiation resistant fusion magnets are particularly beneficial for low cost, low aspect ratio compact reactor designs such as Fusion Nuclear Science Facility (FNSF), Fusion Pilot Plant (FPP) of low-aspect ratio spherical tokamak (ST) or compact stellarators. Unlike typical high field magnets for nuclear magnetic resonance (NMR), magnetic resonance imaging (MRI), or high energy physics research applications, neutron irradiation damage to organic insulations in the coil winding pack is a critical issue for next generation fusion reactors where orders of magnitude higher neutron fluence than those in present experimental reactors such as ITER are expected. Moreover, a high coil winding pack current density is needed for high field magnets in low cost, compact radial build next step fusion reactors. The slow current charging time, however, is an issue in fully non-insulated coils. In this work, we present the design, construction and testing of subscale Nb3Sn solenoids, up to half the diameter of the central solenoid (CS) for National Spherical Torus Experiment (NSTX), with and without inter-layer insulation for enhancing radiation resistance while improving the winding pack current density and coil performance. The major radius for the NSTX/NSTX-Upgrade (reference for compact ST) is 0.854/0.934 meter, and 4.8 meters for FNSF. The magnetic field for NSTX/NSTX-U at the plasma center is 0.6/1 Tesla and 9 Tesla for FNSF. The inner diameter of the central solenoid coil is 0.2/0.4 meter for NSTX/NSTX-U and 1.2 meters for FNSF. The current charging and discharging behavior of the prototype solenoids was investigated to quantify performance advantages of a simplified coil fabrication without error-prone vacuum pressure impregnation (VPI) for the removal of epoxy organic insulation. Scalability of the no insulation concept for fusion can be addressed via engineered coating for novel insulation on contact resistance or intra-layer no insulations. Radiation resistance and coil winding efficiency were significantly improved in the no insulation coils for next step compact fusion reactors.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2016

SU-F-T-461: Dosimetric Evaluation of Indigenous Farmer Type Chamber FAR65- GB for Reference Dosimetry of FFF MV Photon Beam

Purpose: Indigenous Farmer type chamber FAR 65 GB is a reference class 0.6 cc ion chamber. It can be used for dosimetric evaluation of photon and high energy electron beams. We studied dosimetric characteristics of the chamber for 6MV and 10MV Flattening filter free FFF photon beams available on trueBEAM STx Linac. Methods: The study was carried out on trueBEAM STx Linac having 6 and 10 MV FFF photon beam with maximum dose rate 1400 and 2400 MU per min respectively. The dosimetric device to be evaluated is Rosalina Instruments FAR 65-GB Ion Chamber with active volume 0.65 cc, total active length 23.1cm, inner diameter of cylinder 6.2mm, wall thickness 0.4mm, inner electrode diameter 1mm. Inner and outer electrodes are made from Aluminium 2.7 gm per cc and graphite 1.82 gm per cc respectively. The ion chamber was placed along central axis of beam at 10cm depth and irradiated for 10cm × 10cm field size at SAD of 100 cm in plastic phantom. We studied Precision, Dose Linearity, Dose Rate dependence, directional dependence, Recombination effect. Recombination effect was determined using standard two-voltage method. Results: 1. Measurements were reproducible std deviation of 0.0105 and type A uncertainty 0.003265 under same set of reference conditions 2. Chamber exhibit dose linearity over a wider dose range. 3. Chamber shows dose rate independence for all available dose rate range. 4. Response of chamber with the angle of incidence of radiation is constant. 5. Recombination correction factors were 1.01848 and 1.02537 for dose rate 1400 and 2400 MU per min resp. Conclusion: Our study reveals that the chamber is prone to saturation effect at dose rate of 2400 MU per min. FAR 65-GB can be used for reference dosimetry of FFF MV photon beam with proper calculation of recombination effect.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2022

Coupled Thermal-Hydraulic and Fuel Performance Simulations of the TWIST LOCA Commissioning Test Series in TREAT

As the nuclear industry is looking to increase light water reactor (LWR) burnup limits, Idaho National Laboratory has developed an experiment vehicle for the Transient Reactor Test Facility (TREAT) to support high burnup fuel safety testing. One of the main purposes of this vehicle, known as the Transient Water Irradiation System for TREAT (TWIST), is to perform in-pile loss-of-coolant accident (LOCA) experiments on high burnup LWR fuel to investigate phenomena termed fuel fragmentation, relocation, and dispersal (FFRD). Prior to performing experiments on high burnup fuel specimens, a commissioning test series will be performed. The main purpose of the Loss-of-Coolant-Commissioning (LOC-C) test series is to qualify the TWIST device and validate the power coupling between TREAT and the TWIST fuel rod as well as validation of the thermal-hydraulic and fuel performance simulation predictions.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗