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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 901 records · Page 50
All sourcesNASA NTRSDOE OSTI
NASA NTRS2022

A Compact Electron-Proton Spectrometer for Moon / Mars Surface Space Weather Monitoring and Crew Protection (CEPS)

Small mass/low-power sensors are needed for autonomous Moon/Mars surface ops that provide alerts to impending adverse space weather conditions. In order to use current operational forecasting tools, a sensor capable of measuring both high-energy electrons and protons is needed. By combining high-TRL Timepix technology with a CdTe layer, this project leverages known technology to fill a critical gap for surface operations. Typical space weather sensors are at least an order of magnitude higher in mass than is expected from Timepix-based devices and are deployed on robotic assets away from human crews. High fidelity measurements at the crew location and subsequent ability are needed to provide warnings to crews to shelter with a device that can easily be carried on the Lunar and Martian surfaces.​ The aim of this project is the development of compact, low power space weather sensors for crew protection based on the combination of AES flight heritage Timepix hardware with novel CdTe (Cadmium Telluride) sensors. CdTe technology has only recently matured to a point where it can be reliably used with Timepix detectors. These detectors will be able to measure electron spectra in an energy range relevant to the RELEASE model, which is used operationally by NASA to provide crew early warning of Solar Energetic Particle Events as well as protons in the energy ranges relevant to human health allowing for event ‘nowcasting’ and total event crew dose prediction. Compared to existing solutions these detectors will be compact enough to travel with crew, providing a significant advantage to space environment situation awareness. Project results indicate that CdTe-based Timepix sensors respond well to energetic electrons, and particle tracks are sufficiently distinct to be able to measure in a mixed radiation field. Thermal testing results point to a needed design modification to mitigate high temperatures the detector will see in space. Radiation susceptibility testing was conducted to assess the radiation hardness of the CdTe-Timepix assembly. Overall, the assembly continued to operate up to 100 kRad of gamma-ray exposure. The system calibration did show drift over time but recovered once exposure was complete.

Dan James Fry↗
NASA NTRS2023

CEPS – A Compact Electron-Proton Spectrometer

Small mass/low-power sensors are needed for autonomous Moon/Mars surface ops that provide alerts to impending adverse space weather conditions. In order to use current operational forecasting tools, a sensor capable of measuring both high-energy electrons and protons is needed. By combining high-TRL Timepix technology with a CdTe layer, this project leverages known technology to fill a critical gap for surface operations. Typical space weather sensors are at least an order of magnitude higher in mass than is expected from Timepix-based devices and are deployed on robotic assets away from human crews. High fidelity measurements at the crew location and subsequent ability are needed to provide warnings to crews to shelter with a device that can easily be carried on the Lunar and Martian surfaces.​ The aim of this project is the development of compact, low power space weather sensors for crew protection based on the combination of AES flight heritage Timepix hardware with novel CdTe (Cadmium Telluride) sensors. CdTe technology has only recently matured to a point where it can be reliably used with Timepix detectors. These detectors will be able to measure electron spectra in an energy range relevant to the RELEASE model, which is used operationally by NASA to provide crew early warning of Solar Energetic Particle Events as well as protons in the energy ranges relevant to human health allowing for event ‘nowcasting’ and total event crew dose prediction. Compared to existing solutions these detectors will be compact enough to travel with crew, providing a significant advantage to space environment situation awareness. Project results indicate that CdTe-based Timepix sensors respond well to energetic electrons, and particle tracks are sufficiently distinct to be able to measure in a mixed radiation field. Detector response functions were developed for both electrons and protons. Measurement results showed response to both electrons and protons in the energy range of interest for human space flight.

Radiation↗
NASA NTRS2024

Ultra-deep ATCA imaging of 47 Tucanae reveals a central compact radio source

We present the results of an ultradeep radio continuum survey, containing ∼480 hr of observations, of the Galactic globular cluster 47 Tucanae with the Australia Telescope Compact Array. This comprehensive coverage of the cluster allows us to reach rms noise levels of 1.19 μJy beam −1 at 5.5 GHz, 940 nJy beam−1 at 9 GHz, and 790 nJy beam −1 in a stacked 7.25 GHz image. This is the deepest radio image of a globular cluster and the deepest image ever made with the Australia Telescope Compact Array. We identify ATCA J002405.702-720452.361, a faint (6.3 ± 1.2 μJy at 5.5 GHz, 5.4 ± 0.9 μJy at 9 GHz), flat-spectrum (α = −0.31 ± 0.54) radio source that is positionally coincident with the cluster center and potentially associated with a faint X-ray source. No convincing optical counterpart was identified. We use radio, X-ray, optical, and UV data to show that explanations involving a background active galactic nucleus, a chromospherically active binary, or a binary involving a white dwarf are unlikely. The most plausible explanations are that the source is an undiscovered millisecond pulsar or a weakly accreting black hole. If the X-ray source is associated with the radio source, the fundamental plane of black-hole activity suggests a black hole mass of ∼54–6000 M ⊙ , indicating an intermediate-mass black hole or a heavy stellar-mass black hole.

Alessandro Paduano↗
NASA NTRS2024

Evidence for Primordial Alignment: Insights from Stellar Obliquity Measurements for Compact Sub-Saturn Systems

Despite decades of effort, the mechanisms by which the spin axis of a star and the orbital axes of its planets become misaligned remain elusive. In particular, it is of great interest whether the large spin–orbit misalignments observed are driven primarily by high-eccentricity migration—expected to have occurred for short-period, isolated planets—or reflect a more universal process that operates across systems with a variety of present-day architectures. Compact multiplanet systems offer a unique opportunity to differentiate between these competing hypotheses, as their tightly packed configurations preclude violent dynamical histories, including high-eccentricity migration, allowing them to trace the primordial disk plane. In this context, we report measurements of the sky-projected stellar obliquity (λ) via the Rossiter–McLaughlin effect for two sub-Saturns in multiple-transiting systems: TOI-5126 b (λ = 1 ± 48°) and TOI-5398 b (λ = -8.1 +5.3 −6.3 ). Both are spin–orbit aligned, joining a fast-growing group of just three other compact sub-Saturn systems, all of which exhibit spin–orbit alignment. In aggregate with archival data, our results strongly suggest that sub-Saturn systems are primordially aligned and become misaligned largely in the postdisk phase, as appears to be the case increasingly for other exoplanet populations.

Brandon T Radzom↗
DOE OSTI2011

COMPACT CdZnTe-BASED GAMMA CAMERA FOR PROSTATE CANCER IMAGING

In this paper, we discuss the design of a compact gamma camera for high-resolution prostate cancer imaging using Cadmium Zinc Telluride (CdZnTe or CZT) radiation detectors. Prostate cancer is a common disease in men. Nowadays, a blood test measuring the level of prostate specific antigen (PSA) is widely used for screening for the disease in males over 50, followed by (ultrasound) imaging-guided biopsy. However, PSA tests have a high false-positive rate and ultrasound-guided biopsy has a high likelihood of missing small cancerous tissues. Commercial methods of nuclear medical imaging, e.g. PET and SPECT, can functionally image the organs, and potentially find cancer tissues at early stages, but their applications in diagnosing prostate cancer has been limited by the smallness of the prostate gland and the long working distance between the organ and the detectors comprising these imaging systems. CZT is a semiconductor material with wide band-gap and relatively high electron mobility, and thus can operate at room temperature without additional cooling. CZT detectors are photon-electron direct-conversion devices, thus offering high energy-resolution in detecting gamma rays, enabling energy-resolved imaging, and reducing the background of Compton-scattering events. In addition, CZT material has high stopping power for gamma rays; for medical imaging, a few-mm-thick CZT material provides adequate detection efficiency for many SPECT radiotracers. Because of these advantages, CZT detectors are becoming popular for several SPECT medical-imaging applications. Most recently, we designed a compact gamma camera using CZT detectors coupled to an application-specific-integrated-circuit (ASIC). This camera functions as a trans-rectal probe to image the prostate gland from a distance of only 1-5 cm, thus offering higher detection efficiency and higher spatial resolution. Hence, it potentially can detect prostate cancers at their early stages. The performance tests of this camera have been completed. The results show better than 6-mm resolution at a distance of 1 cm. Details of the test results are discussed in this paper.

36 MATERIALS SCIENCE↗
DOE OSTI2012

Three Dimensional Petrography of Kernouve: A Story of Vein Formation, Compaction, and Metamorphism

Metallic veins in ordinary chondrites, like those found in Kernouve (H5, S1), have been attributed to impact or shock processes on the parent body. However, Kernouve is widely known to exhibit few traditional signs of shock loading and has a very old {sup 39}Ar-{sup 40}Ar age (4.46 Ga), making the significance of vein formation in Kernouve unclear. One possibility is early vein formation followed by partial obliteration due to thermal metamorphism. We examine this scenario here. The metal vein in Kernouve can be explained as a pre-metamorphic shock-induced structure, given the evidence for current weak compaction and low shock stage. However, it is not clear how one explains high porosity and low shock stage if the meteorite experienced early shock sufficiently strong to mobilize metal into a vein-like structure. Some combination of unusual conditions during shock (e.g. high temperatures) or mobility of metal during metamorphism may be needed. One possible mechanism occurring early on the H chondrite parent body follows: blocks of slightly indurated but porous material were disturbed by an impact which caused a physical concentration of metallic phases akin to slickensides. Shearing of these materials caused the warm, ductile metal grains to be concentrated on rock surfaces. This process would have imparted the rocks with indicators cited by as shock induced. This event happened early in the history of the chondrite otherwise shearing forces would have imparted a preferred orientation upon the metal grains. Subsequent annealing due to radiogenic heating erased any preferential orientation and further coalesced the vein metal. The final compaction of the material occurred yielding the porosity seen in the samples today. The material escaped other major shock episodes.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2013

Magnetic Bunch Compression for a Compact Compton Source

A compact electron accelerator suitable for Compton source applications is in design at the Center for Accelerator Science at Old Dominion University and Jefferson Lab. Here we discuss two options for transverse magnetic bunch compression and final focus, each involving a 4-dipole chicane with M_{56} tunable over a range of 1.5-2.0m with independent tuning of final focus to interaction point $\beta$*=5mm. One design has no net bending, while the other has net bending of 90 degrees and is suitable for compact corner placement.

43 PARTICLE ACCELERATORS↗
DOE OSTI2015

Compact Superconducting Radio-frequency Accelerators and Innovative RF Systems

We will present several new technical and design breakthroughs that enable the creation of a new class of compact linear electron accelerators for industrial purposes. Use of Superconducting Radio-Frequency (SRF) cavities allow accelerators less than 1.5 M in length to create electron beams beyond 10 MeV and with average beam powers measured in 10’s of KW. These machines can have the capability to vary the output energy dynamically to produce brehmstrahlung x-rays of varying spectral coverage for applications such as rapid scanning of moving cargo for security purposes. Such compact accelerators will also be cost effective for many existing and new industrial applications. Examples include radiation crosslinking of plastics and rubbers, creation of pure materials with surface properties radically altered from the bulk, modification of bulk or surface optical properties of materials, sterilization of medical instruments animal solid or liquid waste, and destruction of organic compounds in industrial waste water effluents. Small enough to be located on a mobile platform, such accelerators will enable new remediation methods for chemical and biological spills and/or in-situ crosslinking of materials. We will describe one current design under development at Fermilab including plans for prototype and value-engineering to reduce costs. We will also describe development of new nano-structured field-emitter arrays as sources of electrons, new methods for fabricating and cooling superconducting RF cavities, and a new novel RF power source based on magnetrons with full phase and amplitude control.

43 PARTICLE ACCELERATORS↗
DOE OSTI2016

A Variable Energy CW Compact Accelerator for Ion Cancer Therapy

Cancer is the second-largest cause of death in the U.S. and approximately two-thirds of all cancer patients will receive radiation therapy with the majority of the radiation treatments performed using x-rays produced by electron linacs. Charged particle beam radiation therapy, both protons and light ions, however, offers advantageous physical-dose distributions over conventional photon radiotherapy, and, for particles heavier than protons, a significant biological advantage. Despite recognition of potential advantages, there is almost no research activity in this field in the U.S. due to the lack of clinical accelerator facilities offering light ion therapy in the States. In January, 2013, a joint DOE/NCI workshop was convened to address the challenges of light ion therapy [1], inviting more than 60 experts from diverse fields related to radiation therapy. This paper reports on the conclusions of the workshop, then translates the clinical requirements into accelerat or and beam-delivery technical specifications. A comparison of available or feasible accelerator technologies is compared, including a new concept for a compact, CW, and variable energy light ion accelerator currently under development. This new light ion accelerator is based on advances in nonscaling Fixed-Field Alternating gradient (FFAG) accelerator design. The new design concepts combine isochronous orbits with long (up to 4m) straight sections in a compact racetrack format allowing inner circulating orbits to be energy selected for low-loss, CW extraction, effectively eliminating the high-loss energy degrader in conventional CW cyclotron designs.

43 PARTICLE ACCELERATORS↗
DOE OSTI2019

Test Plan for the Third Reirradiation Heating Test of Fuel Particles from AGR 2 Compact 5-4-2

Post irradiation examination (PIE) and high-temperature heating tests of tristructural isotropic (TRISO)-coated fuel particles and compacts from the second Advanced Gas Reactor (AGR) irradiation experiment, AGR 2, are in progress. This test plan describes the reirradiation and subsequent high-temperature testing of loose fuel particles obtained from AGR 2 Compact 5-4-2. To simulate exposed kernels, four of these particles have been cracked at Oak Ridge National Laboratory (ORNL) to produce localized defects that extend through the TRISO layers (outer pyrolytic carbon, silicon carbide [SiC], and inner pyrolytic carbon) while keeping these layers in place and maintaining the shape and integrity of the kernel. To generate short-lived fission products, these particles will be reirradiated in the Neutron Radiography Reactor (NRAD) at the Hot Fuel Examination Facility (HFEF) at the Idaho National Laboratory (INL) Materials and Fuels Complex prior to heating testing in the Fuel Accident Condition Simulator (FACS) furnace at HFEF. FACS testing will be at 1200°C, and fission products released from the reirradiated particles will be measured. The intention of the test is to assess the retention of short-lived fission products I-131 (t1/2 = 8.02 days) and Xe-133 (t1/2 = 5.2 days) in the fuel kernels at high temperatures.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2019

Test Plan for the Second Reirradiation Heating Test of Fuel Particles from AGR 2 Compact 6-4-1

Post irradiation examination (PIE) and high-temperature heating tests of tristructural isotropic (TRISO)-coated fuel particles and compacts from the second Advanced Gas Reactor (AGR) irradiation experiment, AGR 2, are in progress. This test plan describes the reirradiation and subsequent high-temperature testing of loose fuel particles obtained from AGR 2 compact 6-4-1. Four of these particles will have been cracked, gamma counted, and re-irradiated in the Neutron Radiography (NRAD) reactor prior to the heating test. The heating test will involve heating the particles in the Fuel Accident Condition Simulator (FACS) furnace to a peak temperature of approximately 1600°C while collecting fission products released from the particles for post-heating test analysis. The intention of the test is to assess the retention of fission products in the fuel kernel. Reirradiation of the particles will allow a determination of the retention of short-lived fission products I-131 (t1/2 = 8.02 days) and Xe-133 (t1/2 = 5.2 days) in the kernel.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2019

Test Plan for Cyclic Heating of AGR-3/4 Compact 8-1

Post irradiation examination (PIE) and heating tests of tristructural isotropic (TRISO)-coated fuel particles, fuel compacts, and graphite from Advanced Gas Reactor (AGR) irradiation experiment AGR 3/4 are in progress. The AGR-3/4 test train consisted of twelve separate capsules irradiated in the northeast flux trap of the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) from December 14, 2011, to April 12, 2014 (Collin 2015). The plan for the reirradiation in the Neutron Radiography Reactor (NRAD) and subsequent 1200°C heating test of AGR-3/4 Compact 8-1 in the Fuel Accident Condition Simulator (FACS) furnace was described previously in (Stempien 2019). One of the main goals of that test was to assess the retention of short-lived fission products I-131 (t1/2 = 8.02 d) and Xe-133 (t1/2 = 5.2 d) in fuel kernels. Xe-133 release had ostensibly leveled off after approximately 80 hours. An issue with the condensation plate exchanges forced this test to be stopped after approximately 96 hours. The issue was resolved, and the test was restarted by heating FACS back up to 1200°C. During this reheating phase, an additional release of Xe-133, approximately equal in size to the release during the initial heating to 1200°C, was detected in the fission gas monitoring system (FGMS). To test whether this release is related to temperature transients (i.e. from heating and reheating), this new plan will describe three additional temperature cycles.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2019

Irradiated AGR-2 Compacts 5-1-1, 5-1-2, and 5-3-1 Examination Plan

This plan describes post-irradiation examination (PIE) activities (simultaneous three-compact temperature transient safety testing and optional post-safety test analyses) to be performed by Oak Ridge National Laboratory (ORNL) on irradiated Compacts 5-1-1, 5-1-2, and 5-3-1 taken from the Advanced Gas Reactor (AGR) experiment, AGR 2. This work will be performed in accordance with general objectives outlined in the AGR-2 PIE plan and guidance in the ORNL PIE statement of work.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2018

Test Plan for the Reirradiation Heating Test of Fuel Particles from AGR 2 Compact 5-4-2

Post irradiation examination (PIE) and high-temperature heating tests of tristructural isotropic (TRISO)-coated fuel particles and compacts from the second Advanced Gas Reactor (AGR) irradiation experiment, AGR 2, are in progress. This test plan describes the reirradiation and subsequent high-temperature testing of loose fuel particles obtained from AGR 2 Compact 5-4-2. To simulate exposed kernels, four of these particles have been cracked at Oak Ridge National Laboratory (ORNL) to produce localized defects that extend through the TRISO layers (outer-pyrolytic carbon [OPyC], silicon carbide [SiC], and inner-pyrolytic carbon [IPyC]) while keeping these layers in-place and maintaining the shape and integrity of the kernel. To generate short-lived fission products, these particles will be reirradiated in the Neutron Radiography (NRAD) reactor prior to heating testing in the Fuel Accident Condition Simulator (FACS) furnace. FACS testing will be at 1600°C, and fission products released from the reirradiated particles will be measured. The intention of the test is to assess the retention of short-lived fission products I-131 (t1/2 = 8.02 days) and Xe-133 (t1/2 = 5.2 days) in the fuel kernels at accident temperatures.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2020

Conjugate Heat Transfer Analysis of the Supercritical CO2 Based Counter Flow Compact 3D Heat Exchangers

Compact heat exchangers using supercritical fluids such as CO2 are preferred due to their high heat transfer capacity and smaller footprint. Three-dimensional conjugate forced convection heat transfer analysis was performed on several shell-and-tube counter-flow microchannel heat exchangers. Numerical simulations were conducted to test effect of change in mass flow rate, hydraulic diameter and various cross sections on the heat transfer. Increasing mass flow rate improved heat transfer up to a maximum value and then decreased downstream with increasing turbulence. Maximum heat transfer was obtained for the micro channel with the smallest hydraulic diameter. Amongst the cross sections analyzed (circular, square, circular with radial ribs, and square with radial ribs), the most uniform distribution of temperature and maximum heat transfer were obtained for circular cross section with radial ribs. An optimally efficient operation of such a heat exchanger can be attained by considering these factors during multi-objective constrained optimization of geometric parameters and requirements for additive manufacturing of such compact heat exchangers.

Chitale, Janhavi↗
DOE OSTI2021

Compact folded metasurface spectrometer

Compact optical devices such as spectrometers are realized with metasurfaces within a dielectric medium confined by reflective surfaces. The metasurfaces control the phase profiles of the reflected electromagnetic waves within the device. In a compact spectrometer, the metasurfaces within the device separate the electromagnetic waves in different wavelengths. The metasurfaces are designed according to their phase profile by varying the size of the array of scatterers.

Faraji-Dana, MohammadSadegh↗
DOE OSTI2014

INVESTIGATION AND OPTIMIZATION OF A NEW COMPACT SUPERCONDUCTING CAVITY FOR DEFLECTING AND CRABBING APPLICATIONS

Deflecting and crabbing structures have many applications in current accelera?tor systems. The primary use of a deflecting cavity is to separate a single beam into multiple beams. A crabbing cavity enables the head-on collision at the inter?action point in particle colliders in order to increase the luminosity. The early uses of the deflecting structures have been in the early 1960s; these structures were disk loaded structures operating at room temperature. The crabbing structure which was installed at the KEK electron-positron collider was the first and only operational superconducting cavity of that kind. The most common design of superconduct?ing deflecting and crabbing cavities is a squashed-elliptical geometry operating in a TM110-like mode; at low frequencies these structures become challenging due to the large geometrical shapes. Recently, compact deflecting and crabbing structures have been studied for numerous accelerator applications not limited to deflecting or crabbing of beams, but also for beam diagnostics, emittance exchange etc. The rf?dipole design, which is presented here, has evolved from the parallel-bar design and is a new compact deflecting and crabbing design with attractive properties at low frequencies and is operating in a TE11-like mode. The parallel-bar design has been optimized into the rf-dipole design primarily to maximize the net deflection with low and balanced peak surface fields and also to maximize the shunt impedance. The geometries have also been modified to increase the separation between the higher or?der modes, suppress multipacting conditions and reduce multipole components. The design geometries have been improved for mechanical stability in order to withstand thermal and pressure fluctuations under operating conditions. Two superconducting rf-dipole deflecting and crabbing cavities have been designed and optimized at 499 MHz for the Jefferson Lab 12 GeV Upgrade and at 400 MHz for a crabbing cavity for the LHC Luminosity Upgrade. The design optimization, fabrication, and test results of the first prototypes of both designs are presented in detail.

De Silva, Subashini Uddika↗
DOE OSTI2012

A compact breed and burn fast reactor using spent nuclear fuel blanket

A long-life breed-and-burn (B and B) type fast reactor has been investigated from the neutronics points of view. The B and B reactor has the capability to breed the fissile fuels and use the bred fuel in situ in the same reactor. In this work, feasibility of a compact sodium-cooled B and B fast reactor using spent nuclear fuel as blanket material has been studied. In order to derive a compact B and B fast reactor, a tight fuel lattice and relatively large fuel pin are used to achieve high fuel volume fraction. The core is initially loaded with an LEU (Low Enriched Uranium) fuel and a metallic fuel is used in the core. The Monte Carlo depletion has been performed for the core to see the long-term behavior of the B and B reactor. Several important parameters such as reactivity coefficients, delayed neutron fraction, prompt neutron generation lifetime, fission power, and fast neutron fluence, are analyzed through Monte Carlo reactor analysis. Evolution of the core fuel composition is also analyzed as a function of burnup. Although the long-life small B and B fast reactor is found to be feasible from the neutronics point of view, it is characterized to have several challenging technical issues including a very high fast neutron fluence of the structural materials. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗