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NASA NTRS1980

A quadratic analog-to-digital converter

An analog-to-digital converter with a square root transfer function has been developed for use with a pair of CCD imaging detectors in the White Light Coronagraph/X-ray XUV Telescope experiment to be flown as part of the Internal Solar Polar Mission. It is shown that in background-noise-limited instrumentation systems a quadratic analog-to-digital converter will allow a maximum dynamic range with a fixed number of data bits. Low power dissipation, moderately fast conversion time, and reliability are achieved in the proposed design using standard components and avoiding nonlinear elements.

Harrison, D. C.↗

NASA NTRS2001

Dayside Aurora Dynamics

Images from the FUV (Far UltraViolet) instrument on board the IMAGE spacecraft will be presented to demonstrate the auroral dynamics in the dayside auroral zone and the polar cap region. optical emissions detected by three different detectors of FUV come from precipitations of energetic protons, electrons, and both species, respectively. In general, auroral activities in these regions responded very well to variations in the boundary conditions either external or internal to the magnetosphere, i.e., in the solar wind or the magnetotail. As a result, auroral images from FUV provide an excellent tool to investigate particle acceleration and transport processes within the geospace, such as shock acceleration, substorm injections, etc. we will interpret the observed auroral images using various models, discuss difference and similarity in the auroral activity from several typical cases, and assess conditions optimal to each type of auroral activity.

Spann, James F.↗

NASA NTRS1999

Polarization Characteristics of Spectralon Illuminated by Coherent Light

The Multi-angle Imaging Spectroradiometer (MISR) makes use of an on-board calibration system to provide routine absolute radiometric calibrations of the instrument while in flight. In addition to on-board detector standards, two spectralon panels will reflect sunlight into the nine cameras.

reflectance standards spectralon polarization↗

NASA NTRS2019

Benchmarking Simulations of the Compton Spectrometer and Imager with Calibrations

The Compton Spectrometer and Imager (COSI) is a balloon-borne 𝛾-ray (0.2-5 MeV) telescope designed to study astrophysical sources. COSI employs a compact Compton telescope design utilizing 12 high-purity germanium double-sided strip detectors and is inherently sensitive to polarization. In 2016, COSI was launched from Wanaka, New Zealand and completed a successful 46-day flight on NASA’s new Super Pressure Balloon. In order to perform imaging, spectral, and polarization analysis of the sources observed during the 2016 flight, we compute the detector response from well-benchmarked simulations. As required for accurate simulations of the instrument, we have built a comprehensive mass model of the instrument and developed a detailed detector effects engine which applies the intrinsic detector performance to Monte Carlo simulations. The simulated detector effects include energy, position, and timing resolution, thresholds, dead strips, charge sharing, charge loss, crosstalk, dead time, and detector trigger conditions. After including these effects, the simulations closely resemble the measurements, the standard analysis pipeline used for measurements can also be applied to the simulations, and the responses computed from the simulations are accurate. We have computed the systematic error that we must apply to measured fluxes at certain energies, which is 6.3% on a rage. Here we describe the detector effects engine and the benchmarking tests performed with calibrations.

Sleator, Clio C.↗

NASA NTRS1985

Bevalac calibration of the SOFIE range and hodoscope detectors

The scintillating optical fiber isotope experiment (SOFIE) is a Cerenkov-dE/dx-Range experiment which was developed initially for balloon flight to study the isotopic composition of cosmic rays in the iron region. The electronic range and hodoscope detectors use scintillating optical fibers to image the tracks of stopping charged particles and to determine their trajectory. The particle range is determined and used together with a Cerenkov measurement to determine the mass of the stopping particle. Preliminary results of a Bevalac calibration performed in August, 1984 with a prototype of the balloon flight instrument, to study the measurement precision in range and trajectory which could be attained with this detector are described.

Binns, W. R.↗

NASA NTRS2001

GEOS Instrument of Opportunity (IoO)

NOAA's three-axis stabilized series of GOES satellites have a place reserved on the Earth-facing side for an Instrument of Opportunity (IoO). The IoO slot is a location for new technologies that provide space-time-spectral resolution of the environment not possible with the preconceived Imager and Sounder. For example, candidate IoO's have usually proposed to use large-format staring arrays of detectors. The size, weight, power, data rate, and interface allocations for the IoO are modest in comparison to the Imager and Sounder, but the resources are large enough to allow for the collection of useful real time data. Because, the geosynchronous location is ideal for monitoring rapidly changing unpredictable events, IoO's have been suggested to detect lightning, volcanism, ozone and sulfur dioxide, ocean color, vegetation, special weather events, and even broadcast color TV. To become an IoO on GOES, the proposed instrument must: 1) have potential benefit to NOAA, 2) fit within the allocation constraints, 3) be independently funded, including pre-launch test equipment and the spacecraft accommodation costs, 4) be delivered two years before launch for integration and testing, and 5) not interfere with the existing launch schedule or the operational instruments.

Chesters, Dennis↗

DOE OSTI2026

Evaluation of an event-driven 3FI ASIC for spectroscopic X-ray detection with synchrotron radiation

The novel design and evaluation on the NSLS-II beamline of the 3FI application-specific integrated circuit (ASIC) bump-bonded to a simple, planar, 2D segmented silicon sensor are presented. The ASIC was developed for full-field fluorescence spectral X-ray imaging (3FI). It is a small-scale prototype that features a square array of 32 × 32 pixels, and the size of the pixels is 100 µm × 100 µm. The ASIC was implemented in a 65 nm CMOS integrated circuit fabrication process. Each pixel incorporates a charge-sensitive amplifier, a shaping filter, a discriminator, a peak detector and a sample-and-hold circuit, allowing detection of events and storage of signal amplitudes. The system operates in a frameless event-driven readout mode, outputting analog values for threshold-triggered events, allowing high-speed multi-element X-ray fluorescence data acquisition. The 3FI ASIC achieves per-channel spectrometric performance at a power consumption of only 200 µW per pixel, with nearly all dissipation confined to the analog front-end. An energy resolution is measured at the level of 308 eV full width at half-maximum (FWHM) at 8.04 keV (Cu Kα), and 138 eV FWHM at 3.69 keV (Ca Kα). This per-pixel capability makes the prototype suitable for in situ trace element microanalysis in biological and environmental studies. Moreover, the frameless architecture of the detector is designed to address limitations of conventional X-ray fluorescence microscopy, which typically requires mechanical scanning, by enabling continuous high-throughput data acquisition in future full-field implementations.

47 OTHER INSTRUMENTATION↗

NASA NTRS1999

In Situ Identification of Mineral Resources with an X-Ray-Optical "Hands-Lens" Instrument

The recognition of material resources on a planetary surface requires exploration strategies not dissimilar to those employed by early field geologists who searched for ore deposits primarily from surface clues. In order to determine the location of mineral ores or other materials, it will be necessary to characterize host terranes at regional or subregional scales. This requires geographically broad surveys in which statistically significant numbers of samples are rapidly scanned from a roving platform. To enable broad-scale, yet power-conservative planetary-surface exploration, we are developing an instrument that combines x-ray diffractometry (XRD), x-ray fluorescence spectrometry (XRF), and optical capabilities; the instrument can be deployed at the end of a rover's robotic arm, without the need for sample capture or preparation. The instrument provides XRD data for identification of mineral species and lithological types; diffractometry of minerals is conducted by ascertaining the characteristic lattice parameters or "d-spacings" of mineral compounds. D-spacings of 1.4 to 25 angstroms can be determined to include the large molecular structures of hydrated minerals such as clays. The XRF data will identify elements ranging from carbon (Atomic Number = 6) to elements as heavy as barium (Atomic Number = 56). While a sample is being x-rayed, the instrument simultaneously acquires an optical image of the sample surface at magnifications from lx to at least 50x (200x being feasible, depending on the sample surface). We believe that imaging the sample is extremely important as corroborative sample-identification data (the need for this capability having been illustrated by the experience of the Pathfinder rover). Very few geologists would rely on instrument data for sample identification without having seen the sample. Visual inspection provides critical recognition data such as texture, crystallinity, granularity, porosity, vesicularity, color, lustre, opacity, and so forth. These data can immediately distinguish sedimentary from igneous rocks, for example, and can thus eliminate geochemical or mineral ambiguities arising, say between arkose and granite. It would be important to know if the clay being analyzed was part of a uniform varve deposit laid down in a quiescent lake, or the matrix of a megabreccia diamictite deposited as a catastrophic impact ejecta blanket. The unique design of the instrument, which combines Debye-Scherrer geometry with elements of standard goniometry, negates the need for sample preparation of any kind, and thus negates the need for power-hungry and mechanically-complex sampling systems that would have to chip, crush, sieve, and mount the sample for x-ray analysis. Instead, the instrument is simply rested on the sample surface of interest (like a hand lens); the device can interrogate rough rock surfaces, coarse granular material, or fine rock flour. A breadboard version of the instrument has been deployed from the robotic arm of the Marsokhod rover in field trials at NASA Ames, where large vesicular boulders were x-rayed to demonstrate the functionality of the instrument design, and the ability of such a device to comply with constraints imposed by a roving platform. Currently under development is a flight prototype concept of this instrument that will weigh 0.3 kg, using about 4500 J of energy per sample analysis. It requires about 5 min. for XRD analysis, and about 30 min. for XRF interrogation. Its small mass and rugged design make it ideal for deployment on small rovers of the type currently envisaged for the exploration of Mars (e.g., Sojourner-scale platforms). The design utilizes a monolithic P-N junction photodiode pixel array for XRD, a Si PIN photodiode/avalanche photodiode system for XRF, and an endoscopic imaging camera system unobtrusively embedded between the detectors and the x-ray source (the endoscope with its board-mounted camera can be adapted for IR light in addition to visible wavelenths. A rugged, miniature (7 cu cm) x-ray source for the instrument has already been breadboarded.

Marshall, J.↗

NASA NTRS2011

Development of the Advanced Energetic Pair Telescope (AdEPT) for Medium-Energy Gamma-Ray Astronomy

Progress in high-energy gamma-ray science has been dramatic since the launch of INTEGRAL, AGILE and FERMI. These instruments, however, are not optimized for observations in the medium-energy (approx.0.3< E(sub gamma)< approx.200 MeV) regime where many astrophysical objects exhibit unique, transitory behavior, such as spectral breaks, bursts, and flares. We outline some of the major science goals of a medium-energy mission. These science goals are best achieved with a combination of two telescopes, a Compton telescope and a pair telescope, optimized to provide significant improvements in angular resolution and sensitivity. In this paper we describe the design of the Advanced Energetic Pair Telescope (AdEPT) based on the Three-Dimensional Track Imager (3-DTI) detector. This technology achieves excellent, medium-energy sensitivity, angular resolution near the kinematic limit, and gamma-ray polarization sensitivity, by high resolution 3-D electron tracking. We describe the performance of a 30x30x30 cm3 prototype of the AdEPT instrument.

Hunter, Stanley D.↗

NASA NTRSDate not supplied

Future Lightning Instruments for Weather and Climate Monitoring From LEO

Lightning is not only a natural hazard, but it also holds information about physical processes at work in deep convection and influences atmospheric oxidants that modulate ozone and methane. Hence, spaceborne lightning observations are essential for monitoring extreme events and feedbacks in Earth’s climate system. Low-Earth orbiting (LEO) lightning mapping instruments established a 25-year record of global lightning activity and resulted in a wealth of studies that motivated its designation as an Essential Climate Variable by the World Meteorological Organization. Although geostationary observations of lightning have become increasingly available since 2017, LEO lightning mappers continue to serve critical needs given their unique vantage point and acceptance as a unifying reference for geostationary lightning mapper and ground-based global lightning datasets. At the close of 2023, the Lightning Imaging Sensor (LIS) will cease operations on the International Space Station, which introduces a critical gap in LEO-based monitoring of global lightning activity. To address this need, NASA is developing new lightning mapping technology that enables future LEO-based satellite missions. Existing LEO-based lightning mappers rely on narrowband optical emissions centered on 777.4-nm and detectors that capture 500 images per second to detect lightning both day and night. Lightning can also produce optical emissions in a narrowband centered on 337-nm without any corresponding emissions at the traditionally used near-infrared (NIR) wavelength. These near-ultraviolet (UV) emissions are associated with earlier stage electrical breakdown (e.g., streamers), may frequent intense regions of deep convective storms, and may be a significant source of nitrogen oxide production in the upper atmosphere. A new lightning mapping instrument called the CubeSat Lightning Imaging and Detection Experiment (CLIDE) is being designed at NASA Marshall Space Flight Center to use high-speed, scientific CMOS image sensors capable of detecting lightning’s transient optical emissions in the near-UV and NIR during both daylit and nighttime scenes. This will extend the record of global lightning activity and help pave the way for future small satellite missions that combine radio and optical lightning detectors to obtain novel three-dimensional maps of lightning on a global scale, which can revolutionize the way lightning is used to monitor weather and understand changes in climate.

lightning↗

NASA NTRS1993

Lunar Scout Infrared Detector (LSIRD): Simple low-cost imaging spectrometer

A novel design for a compact, light weight, imaging spectrometer has been proposed for an orbiting Lunar mapping mission. Simple in design, its dual arm optical system employs a transmission grating and a dichroic mirror to provide continous two-octave spectral response. The grating's first order wavelengths are reflected into the SWIR arm, while the second order wavelenghts are transmitted to the VNIR arm. The instrument design is that of a push broom camera. It uses one of the detector(s) dimensions for spectral selection, the other detector(s) dimension for cross-track spatial selection, and the foward motion of the platform (in this case, a spececraft) for down-track spatial coverage.

Lunar↗

DOE OSTI2024

Quantification and visualization of uncertainties in reconstructed penumbral images of implosions at Omega

Penumbral imaging is a technique used in plasma diagnostics in which a radiation source shines through one or more large apertures onto a detector. To interpret a penumbral image, one must reconstruct it to recover the original source. The inferred source always has some error due to noise in the image and uncertainty in the instrument geometry. Interpreting the inferred source thus requires quantification of that inference’s uncertainty. Markov chain Monte Carlo algorithms have been used to quantify uncertainty for similar problems but have never been used for the inference of the shape of an image. Because of this, there are no commonly accepted ways of visualizing uncertainty in two-dimensional data. This paper demonstrates the application of the Hamiltonian Monte Carlo algorithm to the reconstruction of penumbral images of fusion implosions and presents ways to visualize the uncertainty in the reconstructed source. This methodology enables more rigorous analysis of penumbral images than has been done in the past.

Instruments & Instrumentation↗

DOE OSTI2021

Beamline Spectroscopy of Integrated Circuits With Hard X-Ray Transition Edge Sensors at the Advanced Photon Source

At Argonne National Laboratory, we are developing hard X-ray (2 to 20 keV) Transition Edge Sensor (TES) arrays for beamline science. The significantly improved energy resolution provided by superconducting detectors compared to semiconductor-based energy-dispersive detectors, but with better collection efficiency than wavelength-dispersive instruments, will enable greatly improved X-ray emission and absorption spectroscopic measurements. Additionally, a prototype instrument with 24 microwave-frequency multiplexed pixels is now in testing at the Advanced Photon Source (APS) 1-BM beamline. Initial measurements show an energy resolution ten times better (150 eV compared to < 15 eV) than the silicon-drift detectors currently available to APS beamline users, and in particular demonstrate the ability to resolve closely-spaced emission lines in samples containing multiple transition metal elements, such as integrated circuits. Comparing fluorescence spectra of integrated circuits measured with our TESs at the beamline to those measured with silicon detectors, we find emission lines and elements largely hidden (e.g. Hf alongside Cu) from a semiconductor-based detector but well resolved by a TES. This directly shows the strengths of TES-based instruments in fluorescence mapping.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

NASA NTRS1981

Neutron star binaries, pulsars and burst sources

Unresolved issues involving neutron star binaries, pulsars, and burst sources are described. Attention is drawn to the types of observations most likely to resolve them. Many of these observations are likely to be carried out during the next decade by one or more missions that have been approved or proposed. Flux measurements with an imaging detector and broad-band spectroscopic studies in the energy range 30-150 keV are discussed. The need for soft X-ray and X-ray observations with an instrument which has arcminute angular resolution and an effective area substantially greater than of ROSAT or EXOSAT is also discussed.

Lamb, F. K.↗

NASA NTRS2004

A 90GHz Bolometer Camera Detector System for the Green Bank Telescope

We describe a close-packed, two-dimensional imaging detector system for operation at 90GHz (3.3mm) for the 100 m Green Bank Telescope (GBT) This system will provide high sensitivity (<1mjy in 1s rapid imaging (15'x15' to 250 microJy in 1 hr) at the world's largest steerable aperture. The heart of this camera is an 8x8 close packed, Nyquist-sampled array of superconducting transition edge sensor bolometers. We have designed and are producing a functional superconducting bolometer array system using a monolithic planar architecture and high-speed multiplexed readout electronics. With an NEP of approx. 2.10(exp 17) W/square root Hz, the TES bolometers will provide fast linear sensitive response for high performance imaging. The detectors are read out by and 8x8 time domain SQUID multiplexer. A digital/analog electronics system has been designed to enable read out by SQUID multiplexers. First light for this instrument on the GBT is expected within a year.

Benford, Dominic J.↗

NASA NTRS2004

A 90GHz Bolometer Camera Detector System for the Green

We describe a close-packed, two-dimensional imaging detector system for operation at 90GHz (3.3 mm) for the 100m Green Bank Telescope (GBT). This system will provide high sensitivity (less than 1mJy in 1s) rapid imaging (15'x15' to 150 micron Jy in 1 hr) at the world's largest steerable aperture. The heart of this camera is an 8x8 close-packed, Nyquist-sampled array of superconducting transition edge sensor (TES) bolometers. We have designed and are producing a functional superconducting bolometer array system using a monolithic planar architecture and high-speed multiplexed readout electronics. With an NEP of approximately 2 x 10(exp -17) W/square root of Hz, the TES bolometers will provide fast, linear, sensitive response for high performance imaging. The detectors are read out by an 8x8 time domain SQUID multiplexer. A digital/analog electronics system has been designed to enable read out by SQUID multiplexers. First light for this instrument on the GBT is expected within a year.

Benford, Dominic J.↗

NASA NTRSDate not supplied

Ground to Air Testing of a Fused Optical-Radar Aircraft Detection and Tracking System

Onboard detection and tracking capability are integral to the sensing component in collision avoidance systems needed to safely operate autonomous urban air taxis and small Unmanned Aircraft Systems. Ground-based validation of detection and tracking systems is an important milestone towards the end goal of real-time collision avoidance using onboard sensors and algorithms. In this work, we evaluate three Extended Kalman Filter(EKF)based fusion trackers with radar and vision detection inputs, and compare them with baseline trackers for each sensor type. Performance is assessed using field collected data of ground to air test flights with the sensors co-located on a stable platform with an instrumented multirotor acting as the intruder performing a waypoint pattern at a distance of1.1km to 0.3km to simulate a head-on collision geometry. Fusing an image-based morphological detector with a radar detector using an EKF covered 74% of the ground truth position updates logged by the flight controller on the multirotor within 50 meters after accounting for alignment offsets while covering 15% more ground truth updates relative to radar only. Removing timestamps when the intruder aircraft is occluded by trees and only considering timestamps where the radar has an update, the EKF image-based morphological detector combined with the radar detector covered 90% of the of the ground truth position updates within 50metersand 97% within 100 meters.

Chester V Dolph↗

NASA NTRS2004

MODIS Solar Diffuser Attenuation Screen Modeling Results

On-orbit calibration of the reflected solar bands on the EOS Moderate Resolution Imaging Spectroradiometer (MODIS) is accomplished by have the instrument view a high reflectance diffuse surface illuminated by the sun. For some of the spectral bands this proves to be much too bright a signal that results in the saturation of detectors designed for measuring low reflectance (ocean) surfaces signals. A mechanical attenuation device in the form of a pin hole screen is used to reduce the signals to calibrate these bands. The sensor response to solar illumination of the SD with and without the attenuation screen in place will be presented. The MODIS detector response to the solar diffuser is smooth when the attenuation screen is absent, but has structures up to a few percent when the attenuation screen is present. This structure corresponds to non-uniform illumination from the solar diffuser. Each pin hole produces a pin-hole image of the sun on the solar diffuser, and there are very many pin hole images of the sun on the solar diffuser for each MODIS detector. Even though there are very many pin-hole images of the sun on the solar diffuser, it is no longer perfectly uniformly illuminated. This non-uniformly illuminated solar diffuser produces intensity variation on the focal planes. The results of a very detailed simulation will be discussed which show how the illumination of the focal plane changes as a result of the attenuation, and the impacts on the calibration will be discussed.

Waluschka, Eugene↗