- API data.nasa.gov | Last Updated 2018-09-05T23:05:09.000Z
<p>Develop barrier infrared detector technology for the nation’s needs in high-performance SWIR (short-wavelength infrared), MWIR (mid-wavelength infrared), and LWIR (long-wavelength infrared) imaging focal plane arrays (FPAs).</p><p>Under the enhanced barrier infrared detector and focal plane array project we are developing a compatible family of high-performance SWIR (short-wavelength infrared), MWIR (mid-wavelength infrared), and LWIR (long-wavelength infrared) detectors for focal plane array (FPA) applications. The barrier infrared detectors features infrared absorbers with adjustable cutoff wavelengths. They make use of the unipolar barrier device architecture in which the unipolar barriers serve to reduce generation-recombination dark current, but allow the un-impeded collection of photo-generated carriers. The high-performance, cost-effective infrared detector and focal plane array technology has a variety of potential applications. The main applications include infrared imaging systems and imaging spectrometers. The cost-effective infrared detector and imaging focal plane array technology under development in this project provides high FPA performance (high operability, high uniformity, high operating temperature, low 1/f noise). It is suitable for infusion into operational systems of many NASA, Defense, and industrial applications.</p>
- API data.nasa.gov | Last Updated 2018-09-07T17:37:54.000Z
<p style="margin-left:0in; margin-right:0in">The overall objective of the SBIR is to develop a high performance, inexpensive, three-band thermal infrared camera system, suitable for deployment in Unmanned Airborne Systems and CubeSats. This imaging system will be capable of mapping thermal features on the surface of the earth with a high revisit rate and high spatial resolution. Xiomas believes the Three Band Infrared Detector (TBIRD) System will see significant demand as a small multiband thermal sensor onboard small to medium sized unmanned airborne vehicles (UAV) and space-based cubesat applications, in both the commercial and military markets.</p> <p style="margin-left:0in; margin-right:0in"> </p> <p style="margin-left:0in; margin-right:0in">Xiomas has extensive experience in most of the fundamental technologies proposed. In Phase II we propose to develop a flight ready TRL 7 prototype, with the final six months of Phase II dedicated to instrument calibration and characterization, environmental tests (shock, vibration, temperature, etc.), and flight tests in manned or unmanned small aircraft. </p> <p style="margin-left:0in; margin-right:0in"> </p> <p style="margin-left:0in; margin-right:0in">The system will be useful for a wide variety of environmental research, disaster response, wildfire science, wildfire detection and mapping, oil spill mapping and detection, and thermal anomaly mapping in general.</p>
- API data.nasa.gov | Last Updated 2018-07-19T08:11:39.000Z
The innovation is a new Stretched Lens Array (SLA) with a thinner, lighter, more robust Fresnel lens (with thin glass or polymer superstrate or embedded aluminum mesh). The new lens enables a blanket-level specific power > 1,000 W/kg, including lenses, PV cell circuit (including cells, encapsulation, high-voltage insulation, and heavy radiation shielding), and waste heat rejection radiator. The new SLA array is cost-effective, with the most expensive array cost element, the IMM solar cell, contributing only $50/W to the array cost. The new lens is novel in configuration, enabling single-axis tracking for the array even in the presence of large beta angles (e.g., 50 degrees) between the array and the sun. For future high-power arrays (e.g., > 100 kW), including Solar Electric Propulsion (SEP) missions, the new SLA will offer a unique combination of high efficiency (e.g., >35%), ultra-low mass, high-operating voltage (e.g., >300 V), and low cost. SLA technology is a direct descendant of the SCARLET array used to power NASA's Deep Space 1 SEP mission in 1998-2001. SLA recently completed a flight test on TacSat 4 in a very high radiation orbit, and the lessons learned from TacSat 4 led to the new SLA, the subject of this proposal. The new SLA is scalable to multi-hundred-kW array sizes using blanket deployment and support platforms such as DSS's Roll-Out Solar Array (ROSA). The new SLA will typically operate at 4X concentration, saving substantially on solar cell area, cost, radiation shielding mass, and dielectric isolation mass. The new SLA will enable the early use of state-of-the-art cells, such as inverted metamorphic (IMM) cells with 4 or 6 junctions, and will enhance the production capacity of cell vendors (e.g., 100 kW per year of 1 sun cells = 400 kW per year of 4X cells). The feasibility of the new SLA was firmly established in Phase I, and fully functional prototype hardware will be developed and tested by MOLLC, DSS, SolAero-Emcore, and CFE in Phase II.
Interferometric Correlator for Acoustic Radiation & Underlying Structural Vibration (ICARUSV), Phase IIdata.nasa.gov | Last Updated 2018-07-19T08:11:57.000Z
Current methods for identification of aircraft noise sources, such as near-field acoustical holography and beam forming techniques, involve the use of pressure probes or microphone arrays to measure the radiated sound field. However, those techniques are intrusive, bandwidth limited, time consuming to implement, require extensive data processing and the resulting data may ultimately generate false results in the form of pseudo (noise) sources. Advanced Systems & Technologies Inc. proposes an optical non-contact sensor fusion concept which, for the first time, enables direct capture and observation of full-field non-stationary dynamic structural vibrations (SV) and unsteady radiated sound fields or transient flow fields around the structure of interest. SV depict the flow of energy in a structure and provides an unambiguous identification of structural noise sources and sinks. Additionally, the ability to capture and correlate the acoustic/flow field data with the structure borne intensity, offers an unprecedented and rapid diagnostic capability for noise source characterization and evaluation of noise abatement systems. In addition to being non-intrusive the measurements are fast, can be made at operationally relevant bandwidths, which extend to the ultrasonic domain, and provide deeper insight into the complex structural dynamics which are the root cause of noise emission.
- API data.nasa.gov | Last Updated 2018-07-19T15:53:33.000Z
An integrated framework is proposed for efficient prediction of rotorcraft and airframe noise. A novel wavelet-based multiresolution technique and high-order accurate WENO scheme is proposed for efficient capturing of noise sources and unsteady flowfield. A wavelet compression is used to store the flowfield as a multi-level representation in functional space. The primary solution progresses using a coarse grid. The regularity of the flow field data is used to identify regions of steep variation. These regions are selectively solved recursively in the finer grid-levels and accurate information is injected into the coarse grids to correctly represent all flow features. In Phase I, a three-dimensional wavelet-based multiresolution algorithm, and an acoustic analogy module based on the Kirchhoff-Ffowcs Williams and Hawking methodology will be developed. The feasibility of the proposed technology will be demonstrated by prediction of three-dimensional noise source and acoustic waves of vortex-blade interaction problems. The proposed technology will provide 2-3 orders-of-magnitude reductions in CPU requirements over existing techniques. In Phase II, the wavelet compression methodology will be integrated into a high-fidelity CFD module. An efficient data structure will be developed to store and update the multiresolution data. The modules will be coupled with a nonlinear finite-element structure dynamic module for noise prediction of flexible structures.
- API data.nasa.gov | Last Updated 2018-07-19T08:06:48.000Z
<p>Observations of energetic neutral atoms (ENAs) provide the only way to observe solar energetic particles (SEPs) where they are accelerated. The one observation of solar ENAs to date had low sensitivity, a high energy threshold, and no imaging information. The Solar Energetic Neutral-atom Imaging Coronagraph (SENIC) instrument concept combines large detector area, a low energy threshold, and high angular resolution. The key design challenge for this concept was to minimize the level of stray light illuminating the detectors.<p/><p>Measurements of energetic neutral atoms (ENAs) are a new tool to improve our understanding of energy release and particle acceleration in solar eruptive events. Due to limitations of past observations, even the most basic questions remain unanswered about the acceleration of solar energetic particles (SEPs) by shocks driven by coronal mass ejections (CMEs). ENAs provide the only way to observe SEPs where they are accelerated. The one observation of solar ENAs to date had low sensitivity, a high energy threshold, and no imaging information. The Solar Energetic Neutral-atom Imaging Coronagraph (SENIC) instrument concept is designed to observe ENAs from <~20 keV to a few hundred keV with a spectral resolution as good as 1 keV and image them from 2 R_sun to 40 R_sun with a spatial resolution of 0.1 R_sun. Since ENAs cannot be imaged with focusing optics, this concept uses an indirect imaging technique similar to the one successfully used on RHESSI. Thus, the SENIC instrument concept combines large detector area, a low energy threshold, and high angular resolution.</p>
Creating and Understanding Hybrid Interfaces of Multifunctional Composite Laminates for Extreme Environmentsdata.nasa.gov | Last Updated 2018-07-19T10:56:15.000Z
Due to increasing needs for lightweight and multifunctional structures and materials that can operate at and sustain the extreme environment such as high temperature and pressure, hybrid composites are of high interests and being developed recently. Because of the mismatch in properties of different layers, the interfacial regions in these hybrid systems are critical for reliability. The objectives of this work are to develop a robust and multifunctional interface between shape memory alloys and polymer matrix composite for hybrid materials that undergoes elevated temperatures at the operating environment. Functionalities of this interface include thermo-mechanical capability together with self-sensing and self-healing abilities. Approaches from experimental techniques for manufacturing and characterizing will be used. Computational models across the scales utilizing molecular dynamics, micromechanics and finite element methods will be developed to assist the understanding and interpreting the complex phenomena observed at the interface as well as to help design the interface that meets the specific needs.
- API data.nasa.gov | Last Updated 2018-07-19T10:16:45.000Z
The innovation proposed here is a digital array gas radiometer (DAGR), a new design for a gas filter correlation radiometer (GFCR) to accurately measure and monitor CO2, CO, CH4, N2O and other key trace gases in the boundary layer from space, aircraft or ground-based platforms. GFCR is a well-known and proven technology for trace gas detection and monitoring. However, its effectiveness in downlooking applications has been limited, primarily because variations in surface albedo degrade the performance. Our DAGR approach builds on traditional GFCR concepts and combines several new key elements: two-dimensional detector arrays, pupil imaging (imaging the aperture), and a novel calibration approach. With these enhancements and appropriate signal processing, the DAGR design overcomes the historical limitations of GFCR in downlooking applications. In addition, this design significantly boosts the sensitivity and expands the dynamic range traditionally available to these sensors. Finally, the innovation provides a calibration technique that nearly eliminates errors due to detector drift effects. The result will be a compact, static, robust system that can accurately measure important boundary layer species from a variety of platforms.
Proof-of-concept and feasibility demonstrations for an avalanche photodiode/photoelastic modulator-based imaging polarimeterdata.nasa.gov | Last Updated 2018-07-19T07:18:39.000Z
Building on the successful heritage of JPL’s Multiangle SpectroPolarimetric Imager (MSPI), we propose infusing HgCdTe avalanche photodiode (APD) array technology into the MSPI camera architecture. This concept includes a custom readout integrated circuit (ROIC) that demodulates the 42 kHz waveform from a single photoelastic modulator (PEM) by sorting the APD charge pulses into 3 bins associated with each pixel, from which intensity I and Stokes parameters Q and U are derived. This innovation yields superior signal-to-noise performance and extends MSPI polarimetry into the ultraviolet and midwave infrared, enabling characterization of high-altitude hazes and the vertical gradient of droplet sizes near the tops of liquid water clouds. These new capabilities are important because the recent slowdown in global mean surface temperature rise has been linked to stratospheric aerosols, and cloud-top droplet size information helps mitigate biases in microwave retrievals of precipitation rates. MSPI’s current dual-PEM approach requires two detector rows at any given wavelength to recover I, Q, and U (confining polarimetry to a few bands), and incurs a noise penalty that requires pixel averaging to improve performance and limits the polarimetric spectral range to the visible through shortwave infrared. The proposed technology eliminates one PEM from each camera, reduces mass, and recovers I, Q, and U at all UV-MWIR wavelengths with just one detector row in each band. We will validate this approach in the laboratory using a small APD array. To demonstrate the feasibility of meeting the speed, noise, and power constraints for a large pushbroom array, we will design and simulate the custom ROIC that performs the on-chip temporal multiplexing, and fabricate and test the critical pixel-level charge-sorting circuit. The entry level of this technology is TRL 2. Our 32-month investigation will advance the overall demodulation approach to TRL 3 and the in-pixel sorting circuit to TRL 4.
- API data.nasa.gov | Last Updated 2018-07-19T12:30:50.000Z
<p>MIDN PROTOTYPE FLIGHT INSTRUMENT 1. Based on our experience with the MIDN development, we designed and developed an advanced version of the instrument. 2. A prototype was developed that although did not include all of the specifications was able to achieve with a 10 um thick sensor a dE/dx ~ 3 keV/um in silicon that is equivalent to a lineal energy of ~1 keV/um in tissue. BENCHTOP DEVELOPMENT SYSTEM 1. By designing and constructing a new Faraday cage that houses the sensor and preamplifier circuit, upgrading the signal transmission circuitry between the system and the data acquisition area, and designing a new data acquisition method, we were able to reduce the inherent noise level well below a keV/micron, allowing detection of the peak of the dose distributions for minimum ionizing protons, the most difficult particles to detect microdosimetrically. 2. In collaboration with the M. Sivertz and A. Rusek at BNL, we have developed a system that allows identification of incident particles, categorized them according to their mass-to-charge ratio and energy, and correlated them with individual events in the microdosimeter. Recall that our earlier work in this regard resulted in our identifying lighter ion contaminants in the beam and their contributions to the microdosimetric spectra, a fact that we subsequently learned was known to BNL personnel. 3. We measured the energy deposited in a microdosimeter with radiation beams of Carbon at 290 MeV/n and protons at 1 GeV/n, 600 MeV/n, 250 MeV/n, 100 MeV/n, and 50 MeV/n at the NSRL facility at the BNL and achieved a lower energy cutoff of < 1 keV/um in silicon equivalent to a lineal energy cutoff in tissue of < 0.3 keV/um. ADVANCED SENSOR DEVELOPMENT 1. We now have prototypes of a new design of a solid-state microdosimeter with three dimension micron sized sensitive volumes, addressing some of the shortcomings identified earlier. This sensor was developed at the Centre for Medical Research Physics, and a new grant (Australian Research Council Discovery Project) was recently received by our collaborator to further support this project. 2. We have established collaborations with the EE (electrical engineering) departments at Johns Hopkins University (JHU) to explore the potential of developing alternative silicon sensors. These new sensors will be developed as part of our follow-on grant from the NSBRI. 3. With minimal support, JHU was able to supply us with two dies that have a variety of diodes for preliminary testing. A test fixture was developed to carry out tests, and measurements of alpha particles were successfully conducted. RADIATION TRANSPORT CODES 1. We imported the radiation transport code GEANT4 and two corollary programs MULASSIS (multilayered shielding simulation software tool) and GEMAT. These Monte Carlo codes allow us to simulate the microdosimetry spectra in silicon devices. 2. We also have access to the MCNPX (Monte Carlo N-Particle eXtended) radiation transport code.</p>