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At least 163 records · Page 9

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NASA NTRS1989

Atmospheric autorotating imaging device

An imaging device that automatically rotates upon descent through an atmosphere provides an onboard image detector a sweeping panoramic scan as it descends. No moving parts or propulsion system are required. The location, angle and pitch of the winged structure, together with its inertia properties, passively induces rotation. The angled location of the image detector takes advantage of the resulting rotation. Data generated by the image detector may be transmitted to a remote receiver or, alternatively, stored for subsequent recovery.

Burke, James D.↗

NASA NTRS2002

Superconducting kinetic inductance photon detectors.

We are investigating a novel superconducting detector and readout method that could lead to photon counting, energy resolving focal plane arrays. This concept is intrinsically different from STJ and TES detectors, and in principle could deliver large pixel counts, high sensitivity, and Fano-limited spectral resolution in the ptical/UV/X-ray bands. The readout uses the monotonic relation between the kinetic surface inductance L***subs***, of a superconductor and the density of quasiparticles n, which holds even at temperatures far below T***subc***. This allows a sensitive readout of the number of excess quasiparticles in the detector by monitoring the transmission phase of a resonant circuit. The most intriguing aspect of this concept is that passive frequency multiplexing could be used to read out ~ l0***super4*** detectors with a single HEMT amplifier. Single x-ray events have been observed in prototype detectors.

kinetic↗

DOE OSTI2022

WIRE-21 Sensor Irradiation Experiment Ready for HFIR Insertion

The ability to deploy new nuclear fuels for current or future reactor concepts requires a wealth of data regarding fuel performance during normal operation, anticipated operational occurrences, and design-basis accidents. Most of these data have historically been collected during experiments in materials test reactors, ideally with online instrumentation to collect as much data as possible. However, advanced instrumentation could also allow for in situ monitoring of fuel operating conditions during commercial reactor operation to maximize fuel utilization, reduce unnecessary conservativism in design margins, and improve operator understanding of limiting peaking factors. The latter approach would complicate fuel handling, particularly during refueling, unless the instrumentation could be placed inside the fuel rods and transmitted wirelessly to a receiver located outside the fuel’s primary pressure boundary. To this end, Westinghouse Electric Company (WEC) developed wireless sensors based on inductive coupling that can transmit information regarding fuel centerline temperatures and rod internal pressures wirelessly from within a fuel rod to a nearby instrument thimble. After testing these sensors in lower-power university research reactors, the next step is to perform high neutron fluence testing to characterize the performance of these wireless sensors under conditions that are more representative of the intended application—in this case, light-water reactors (LWRs). The removable Be (RB) positions of the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL) provide the neutron flux, experiment volume, and access to instrument leads required to achieve these sensor testing goals. This report summarizes the design, analysis, and assembly of the Wireless Instrumented RB Experiment 2021 (WIRE-21). This is the most highly instrumented irradiation experiment ever performed in HFIR. The experiment will use seven different sensing techniques to measure temperature, pressure, neutron flux, and neutron fluence during reactor operation. In addition to WEC’s wireless temperature and pressure sensors, WIRE-21 includes an array of thermocouples, self-powered neutron detectors, spatially distributed fiber optic temperature sensors, passive SiC temperature monitors, and flux wires. The design of WIRE-21 and the cabling that was installed in HFIR also provide the infrastructure to enable accelerated, economical testing of advanced sensor technologies while leveraging the extremely high neutron flux that is available in HFIR. The containment for WIRE-21 is similar to previous RB irradiation vehicles but includes a few modifications, most notably the use of integrated compression seals to pass a larger number of sensor leads through the experiment’s pressure boundary. In addition to the sensor leads, inert gas lines are passed into the experiment to enable active temperature control and the ability to pneumatically actuate a bellows-driven pressure sensor. WIRE-21 is targeting component temperatures (300–350°C) and neutron fluence levels (~10 22 n/cm 2 ) that would be expected in the plenum region of LWR fuels, except for the active sensing region of the wireless temperature sensor, which is targeting LWR fuel centerline temperatures (~800–1,100°C). WIRE-21 was successfully assembled, passed all nondestructive examination, and was delivered to HFIR for insertion during upcoming cycle 498 (April 2022).

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

NASA NTRS1980

Heterodyne Systems and Technology, part 2

Various aspects of optical heterodyning are covered including active and passive systems, local oscillators, tunable diode lasers, detectors and related systems.

Source record↗

NASA NTRS1992

Conceptual thermal design and analysis of a far-infrared/mid-infrared remote sensing instrument

This paper presents the conceptual thermal design and analysis results for the Spectroscopy of the Atmosphere using Far-Infrared Emission (SAFIRE) instrument. SAFIRE has been proposed for Mission to Planet Earth to study ozone chemistry in the middle atmosphere using remote sensing of the atmosphere in the far-infrared (21-87 microns) and mid-infrared (9-16 microns) spectra. SAFIRE requires that far-IR detectors be cooled to 3-4 K and mid-IR detectors to 80 K for the expected mission lifetime of five years. A superfluid helium dewar and Stirling-cycle cryocoolers provide the cryogenic temperatures required by the infrared detectors. The proposed instrument thermal design uses passive thermal control techniques to reject 465 watts of waste heat from the instrument.

Roettker, William A.↗

NASA NTRS1979

Design and test of the Near Infrared Mapping Spectrometer /NIMS/ focal plane for the Galileo Jupiter Orbiter mission

A Near Infrared Mapping Spectrometer (NIMS) will fly past Jupiter on the Galileo spacecraft in 1982. The infrared detector assembly (focal plane) used in the NIMS instrument is to be passively cooled to 80 K by radiation into space. The focal plane contains 15 InSb and two silicon detectors, each with an associated dual J-FET preamp and feedback resistor. Preliminary fabrication and test experience will be described for an experimental five-channel hybrid detector assembly. Measurements of spectral noise density along with a plasma cleaning technique will also be described. The final NIMS focal plane will contain much of the design experience gained from the experimental hybrid detector assembly.

Bailey, G.↗

DOE OSTI2022

Optical diagnostics of laser-produced plasmas

Laser-produced plasmas (LPPs) engulf exotic and complex conditions ranging in temperature, density, pressure, magnetic and electric fields, charge states, charged particle kinetics, and gas-phase reactions, based on the irradiation conditions, target geometries, and the background cover gas. The application potential of the LPP is so diverse that it generates considerable interest for both basic and applied research areas. The fundamental research on LPPs can be traced back to the early 1960s, immediately after the invention of the laser. In the 1970s, the laser was identified as a tool to pursue inertial confinement fusion, and since then, several other technologies emerged out of LPPs. These applications prompted the development and adaptation of innovative diagnostic tools for understanding the fundamental nature and spatiotemporal properties of these complex systems. Although most of the traditional characterization techniques developed for other plasma sources can be used to characterize the LPPs, care must be taken to interpret the results because of their small size, transient nature, and inhomogeneities. The existence of the large spatiotemporal density and temperature gradients often necessitates non-uniform weighted averaging over distance and time. Among the various plasma characterization tools, optical-based diagnostic tools play a key role in the accurate measurements of LPP parameters. The optical toolbox contains optical spectroscopy (emission, absorption, and fluorescence), passive and active imaging and optical probing methods (shadowgraphy, Schlieren, interferometry, Thomson scattering, deflectometry, and velocimetry). Each technique is useful for measuring a specific property, and its use is limited to a certain time span during the LPP evolution because of the sensitivity issues related to the selected measuring tool. Therefore, multiple diagnostic tools are essential for a comprehensive insight into the entire plasma behavior. In recent times, the improvements in performance in the lasers and detector systems expanded the capability of the aforementioned passive and active diagnostics tools. Furthermore, this review provides an overview of optical diagnostic tools frequently employed for the characterization of the LPPs and emphasizes techniques, associated assumptions, and challenges. Considering most of the industrial and other applications of the LPP belong to low to moderate laser intensities (10 8 – 10 15 Wcm –2 ), this review focuses on diagnostic tools pertaining to this regime.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

DOE OSTI2023

Micro-Transfer Printing of Repeaters on Passive Interposer

Silicon-based sensors are central to particle physics experiments and particle tracking detectors. New-generation Large Focal Plane Arrays (LFPAs) cover areas that extend beyond several square meters. Distributing power and transporting data across such areas while maintaining good signal integrity is a complicated challenge. Tiling the detector on an organic interposer would be far too expensive and take too much space while offering little to no advantage regarding signal integrity. Passive silicon interposers are much less expensive and more integrable but would worsen signal integrity because of their inherent higher dielectric constant. Active interposers are a good compromise from the economic and signal integrity standpoint; unfortunately, their yield trends to zero for areas greater than a reticle size, making this technology incompatible with our application. NHanced proposes to duplicate the behavior of a high-yield, low-cost active interposer by printing active microcomponents on a passive interposer with our die-to-wafer micro-transfer printing (MTP) technology. This resolves the signal integrity and power distribution limitations. In Phase I, we designed and simulated analog and digital repeaters to be MTPed onto a passive silicon interposer test wafer.

2.5D↗

NASA NTRS1991

Effect of space exposure on pyroelectric infrared detectors

Twenty pyroelectric type infrared detectors were flown onboard the Long Duration Exposure Facility (LDEF). The detector chips were of three different pyroelectric materials: lithium-tantalate, strontium-barium-niobate, and triglycine-sulfide. The experiment was passive; no measurements were taken during the flight. Performance of the detectors was measured before and after flight. Postflight measurements revealed that detectors made of lithium-tantalate and strontium-barium-niobate suffered no measureable loss in performance. Detectors made of triglycine-sulfide suffered complete loss of performance, but so did the control samples of the same material. Repoling of the triglycine-sulfide failed to revive the detectors.

Robertson, James B.↗

NASA NTRS2004

Passive Thermal Compensation of the Optical Bench of the Galaxy Evolution Explorer

The Galaxy Evolution Explorer is an orbiting space telescope that will collect information on star formation by observing galaxies and stars in ultraviolet wavelengths. The optical bench supporting detectors and related optical components used an interesting and unusual passive thermal compensation technique to accommodate thermally-induced focal length changes in the optical system. The proposed paper will describe the optical bench thermal compensation design including concept, analysis, assembly and testing results.

optomechanical design↗

NASA NTRS2016

Performance Analysis of a Hardware Implemented Complex Signal Kurtosis Radio-Frequency Interference Detector

Radio-frequency interference (RFI) is a known problem for passive remote sensing as evidenced in the L-band radiometers SMOS, Aquarius and more recently, SMAP. Various algorithms have been developed and implemented on SMAP to improve science measurements. This was achieved by the use of a digital microwave radiometer. RFI mitigation becomes more challenging for microwave radiometers operating at higher frequencies in shared allocations. At higher frequencies larger bandwidths are also desirable for lower measurement noise further adding to processing challenges. This work focuses on finding improved RFI mitigation techniques that will be effective at additional frequencies and at higher bandwidths. To aid the development and testing of applicable detection and mitigation techniques, a wide-band RFI algorithm testing environment has been developed using the Reconfigurable Open Architecture Computing Hardware System (ROACH) built by the Collaboration for Astronomy Signal Processing and Electronics Research (CASPER) Group. The testing environment also consists of various test equipment used to reproduce typical signals that a radiometer may see including those with and without RFI. The testing environment permits quick evaluations of RFI mitigation algorithms as well as show that they are implementable in hardware. The algorithm implemented is a complex signal kurtosis detector which was modeled and simulated. The complex signal kurtosis detector showed improved performance over the real kurtosis detector under certain conditions. The real kurtosis is implemented on SMAP at 24 MHz bandwidth. The complex signal kurtosis algorithm was then implemented in hardware at 200 MHz bandwidth using the ROACH. In this work, performance of the complex signal kurtosis and the real signal kurtosis are compared. Performance evaluations and comparisons in both simulation as well as experimental hardware implementations were done with the use of receiver operating characteristic (ROC) curves. The complex kurtosis algorithm has the potential to reduce data rate due to onboard processing in addition to improving RFI detection performance.

microwaves↗

NASA NTRS2016

Performance Analysis of a Hardware Implemented Complex Signal Kurtosis Radio-Frequency Interference Detector

radiometers↗

DOE OSTI2021

Microwave diagnostics and passive sensors for pipeline, well-bore, and boiler-tube monitoring

Materials, methods of making, and methods of using an integrated wireless detector for real time interrogating metallic tubular structures comprising: an RF patch antenna; a passive surface acoustic wave (SAW) sensor; and data analytic methodologies. An embodiment relates to interrogating a metallic structure having a uniform cross section using an antenna which launches electromagnetic radiation. A sensor may be located within the structure is configured to re-emit electromagnetic radiation modified depending on parameters for which the sensor has been functionalized. An antenna may receive radiation as modified by the sensor, or may receive the transmitted or backscattered radiation directly, without use of a sensor. The antenna then communicates wirelessly with an interrogator providing data which may be used to understand the operational status of the structure in real-time.

Ohodnicki, Paul R.↗

NASA NTRS2003

Characterization and Analysis of InGaAsSb Detectors

Profiling of atmospheric CO2 at 2 micron wavelength using the LIDAR technique, has recently gained interest. Although several detectors might be suitable for this application, an ideal device would have high gain, low noise and narrow spectral response peaking around the wavelength of interest. This increases the detector signal-to-noise ratio and minimizes the background signal, thereby increasing the device sensitivity and dynamic range. Detectors meeting the above idealized criteria are commercially unavailable for this particular wavelength. In this paper, the characterization and analysis of Sb-based detectors for 2 micron lidar applications are presented. The detectors were manufactured by AstroPower, Inc., with an InGaAsSb absorbing layer and AlGaAsSb passivating layer. The characterization experiments included spectral response, current versus voltage and noise measurements. The effect of the detectors bias voltage and temperature on its performance, have been investigated as well. The detectors peak responsivity is located at the 2 micron wavelength. Comparing three detector samples, an optimization of the spectral response around the 2 micron wavelength, through a narrower spectral period was observed. Increasing the detector bias voltage enhances the device gain at the narrow spectral range, while cooling the device reduces the cut-off wavelength and lowers its noise. Noise-equivalent-power analysis results in a value as low as 4 x 10(exp -12) W/Hz(exp 1/2) corresponding to D* of 1 x 10(exp 10) cmHz(exp 1/2)/W, at -1 V and 20 C. Discussions also include device operational physics and optimization guidelines, taking into account peculiarity of the Type II heterointerface and transport mechanisms under these conditions.

Abedin, M. Nurul↗

NASA NTRS1992

Measurement of the passive attitude control performance of a recovered spacecraft

A novel silver detector incorporated in the Long Duration Exposure Facility (LDEF) has been used to measure the attitude stability of the vehicle. It is thereby established that the LDEF spacecraft maintained a very stable attitude during its nearly 6-year-long flight, notwithstanding a small offset yaw of 8.0 +/- 0.4 deg clockwise from nominal attitude (as viewed from space) and a +/- 0.2-deg oscillation about this offset yaw. LDEF experiments which depend on orientation relative to the forward direction may need to be corrected for the angular offset.

Gregory, J. C.↗

DOE OSTI2020

Dynamically Reconfigurable Data Readout of Pixel Detectors for Automatic Synchronization with Data Acquisition Systems

Reconfigurable detectors with dynamically selectable sensing and readout modes are highly desirable for implementing edge computing as well as enabling advanced imaging techniques such as foveation. The concept of a camera system capable of simultaneous passive imaging and dynamic ranging in different regions of the detector is presented. Such an adaptive-autonomous detector with both spatial and temporal control requires programmable window of exposure (time frames), ability to switch between readout modes such as full-frame imaging and zero-suppressed data, modification of the number of pixel data bits and independent programmability for distinct detector regions. In this work, a method is presented for seamlessly changing time frames and readout modes without data corruption while still ensuring that the data acquisition system (DAQ) does not need to stop and resynchronize at each change of setting, thus avoiding significant dead time. Data throughput is maximized by using a minimum unique data format, rather than lengthy frame headers, to differentiate between consecutive frames. A data control and transmitter (DCT) synchronizes data transfer from the pixel to the periphery, reconfigures the data to transmit it serially off-chip, while providing optimized decision support based on a DAQ definable mode. Measurements on a test structure demonstrate that the DCT can operate at 1 GHz in a 65 nm LP CMOS process.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

NASA NTRS2000

The AstroBiology Explorer (ABE) MIDEX Mission

The Astrobiology Explorer (ABE) is a Medium-Class Explorer (MIDEX) mission concept currently under study at NASA's Ames Research Center. ABE will conduct infrared (IR) spectroscopic observations with much better sensitivity than Infrared Space Observatory (ISO) or the Stratospheric Observatory for Infrared Astronomy program (SOFIA) in order to address outstanding astrobiologically important problems in astrochemistry as well as important astrophysical investigations. The core observational astrobiology program would make fundamental scientific progress in understanding the cosmic history of molecular carbon, the distribution of organic matter in the diffuse interstellar medium, tracing the chemical history of complex organic molecules in the interstellar medium, and the evolution of organic ices in young planetary systems. The ABE instrument concept includes a 0.5 m aperture Cassegrain telescope and a suite of three moderate resolution (R = 1000 - 4000) spectrographs which cover the entire lambda = 2.5-20 micron spectral region. Use of large format (1024 x 1024 pixel or larger) IR detector arrays will allow each spectrograph to cover an entire octave of spectral range per exposure without any moving parts. The telescope is passively cooled by a sun shade to below 65 K, and the detectors are cooled with solid H2 cryogen to approximately 8 K. ABE will be placed in an Earth-trailing one AU solar orbit by a Delta II launch vehicle. This energetically favorable orbit provides a low thermal background, affords good access to the entire sky over the one year mission lifetime, and allows adequate communications bandwidth. The spacecraft will be stabilized in three axes and will be pointed to an accuracy of approximately one arcsecond at ABE's several thousand individual scientific targets.

Greene, Thomas↗

NASA NTRS1995

Dosimetry on STS-42 with the RME APD

Beginning with the STS-42 mission, this laboratory began participating in instrument comparison studies in which space radiation was measured contiguously by passive and active methods. The active instrument was the RME-3 microdosimeter. This instrument measures four-channel LET spectra and employs a tissue-equivalent proportional counter. It is sensitive to the full LET range of ionizing radiation present. Our area passive dosimeter, the RME APD, contained arrays of plastic nuclear track detectors (PNTD's) and thermoluminescent detectors (TLD's). The PNTD's measure LET spectra, while the TLD's measure total absorbed dose. The object of this experiment is to compare the active and passive measurements on the basis of LET spectra, total absorbed dose, and dose equivalent. The STS-42 mission was launched on January 22, 1992, with a flight duration of 8.052 days. The orbit had an inclination of 57 deg and an altitude of 302 km. The shuttle in this orbit is expected to encounter radiation levels dominated by galactic cosmic rays (GCR's) with a lesser contribution from trapped protons in the lower region of the South Atlantic Anomaly (SAA).

Source record↗