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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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All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Continuous full-resolution two-color infrared detector

An apparatus is provided for nanoantenna-enhanced detection of infrared radiation. The apparatus includes one or more detector pixels. A plurality of detector pixels can constitute a focal plane array (FPA). Each detector pixel carries at least a first and a second subpattern of nanoantenna elements, with elements of the second subpattern interpolated between elements of the first subpattern. Each detector pixel also includes separate collection electrodes for collecting photogenerated current from the respective subpatterns.

Goldflam, Michael↗
DOE OSTI2019

MagMicro with Ultra-High Energy Resolution (FY19 Q3 Progress Report)

The fabrication of the MMC detector arrays involves two photolithographic procedures. The first is to fabricate the Nb magnetization coil and pick-up coils, the SQUID preamplifiers and the associated wiring. This is done on a full 4” Si wafer, which is subsequently diced into ~0.5 cm2 SQUID chips and ~1 cm2 detector chips. The detector chips are then processed separately by depositing and patterning the paramagnetic Ag:Er sensor and support structures and then electroplating the Au absorber. In Q3, we have successfully completed the full wafer processing for the 32-pixel MMC detector arrays, diced the 4” wafer into the smaller chips and tested the individual components. The coils have the required critical current, the heat switches have a critical temperature in the desired range, and the SQUIDs have the required low noise. Unfortunately, the sputter deposition of the paramagnetic Ag:Er sensor failed several times. We spent considerable time to trace the problem to contaminations of the purifier for the Ar sputtering gas that had been exposed to atmosphere for an extended time during an earlier clean room upgrade. We then determined that the purifier is not essential for high-quality Ag:Er sensor films (Fig. 1), and successfully deposited the Ag:Er sensor film on the ~1 cm 2 detector chip.

42 ENGINEERING↗
DOE OSTI2018

A 4 x 4 array module of position-sensitive virtual Frisch-grid CdZnTe detectors for gamma-ray imaging spectrometers

Arrays of position-sensitive virtual Frisch-grid CdZnTe (CZT) detectors offer an economical approach to making high efficiency and high energy resolution gamma cameras for spectroscopy and imaging of radioactive sources. There are many application areas for such instruments including gamma-rays astronomy, medical and industrial imaging, nonproliferation and nuclear safeguards. We present the test results from a 4x4 array module coupled to the front-end ASIC. The array houses 16 detectors made of 6x6x20 mm 3 CZT crystals. Each crystal is encapsulated inside an ultrathin polyester shell and furnished with four 5-mm-wide charge-sensing pads placed near the anode on each side of the detector. The pad’s signals are used to measure X-Y coordinates while the cathode signals give the interaction depths (Z coordinates). Combined together the signals provide 3D position information of the interaction points which can be used to correct the detector response non-uniformity. This allows developers to use standard grade (unselected) CZT crystals while retaining high spectroscopic performance comparable with that of the H3D pixelated detectors. The array’s design provides flexibility to replace individual detectors and extend their sizes, potentially increasing upwards of 4 cm in height. We started development of position-sensitive VFG detectors several years ago and today this technology has reached a high-maturity level and is ready to use in practical applications.

3D charge-loss correction↗
DOE OSTI2019

Design and Evaluation of a Pixelated PSD-capable Scintillator Detector with SiPM Readout

We present the detector response comparison between a 10x10 pixellated array of scintillator read out with Anger logic using four 2" Hamamatsu R7724-100 super bialkali photomultiplier tubes (PMT) and a custom Silicon photomultiplier (SiPM) board consisting of 100 C-series 6x6 mm SiPMs from SensL. An array of these pixellated detectors are currently used in the Neutron Coded Aperture (NCA) imaging system. The energy, timing and pulse shape discrimination response using both readout schemes are presented, along with an analysis of multiple scatter events occurring within the block. An evaluation of the impact of photodetector readout on the overall detection efficiency and imaging accuracy is presented.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2022

System, apparatus, and method for determining elemental composition using 4D STEM

The present disclosure relates to transmission electron microscopy for evaluation of biological matter. According to an embodiment, the present disclosure further relates to an apparatus for determining the structure and/or elemental composition of a sample using 4D STEM, comprising a direct bombardment detector operating with global shutter readout, processing circuitry configured to acquire images of bright-field disks using either a contiguous array or non-contiguous array of detector pixel elements, correct distortions in the images, align each image of the images based on a centroid of the bright-field disk, calculate a radial profile of the images, normalize the radial profiles by a scaling factor, calculate the rotationally-averaged edge profile of the bright-field disk, and determine elemental composition within the specimen based on the characteristics of the edge profile of the bright-field disk corresponding to each specimen location.

Bammes, Benjamin↗
DOE OSTI2023

Development of the microcalorimeter and anticoincidence detector for the Line Emission Mapper x-ray probe

The Line Emission Mapper (LEM) is an x-ray probe mission concept that is designed to provide unprecedented insight into the physics of galaxy formation, including stellar and black-hole feedback and flows of baryonic matter into and out of galaxies. LEM incorporates a light-weight x-ray optic with a large-format microcalorimeter array. The LEM detector utilizes a 14k pixel array of transition-edge sensors (TESs) that will provide <2.5 eV spectral resolution over the energy range 0.2 to 2 keV, along with a field-of-view of 30 arcmin. The microcalorimeter array and readout builds upon the technology developed for the European Space Agency’s (ESA’s) Athena/x-ray Integral Field Unit. Here, we present a detailed overview of the base- line microcalorimeter design, its performance characteristics, including a detailed energy resolution budget and the expected count-rate capability. In addition, we outline the current status and plan for continued technology maturation. Behind the LEM array sits a high-efficiency TES-based anticoincidence (antico) detector that will reject cosmic-ray background events. We will briefly describe the design of the antico and plan for continued development.

47 OTHER INSTRUMENTATION↗
DOE OSTI2023

Multi-scale time-resolved electron diffraction: A case study in moiré materials

Ultrafast-optical-pump — structural-probe measurements, including ultrafast electron and x-ray scattering, provide direct experimental access to the fundamental timescales of atomic motion, and are thus foundational techniques for studying matter out of equilibrium. High-performance detectors are needed in scattering experiments to obtain maximum scientific value from every probe particle. Here we deploy a hybrid pixel array direct electron detector to perform ultrafast electron diffraction experiments on a WSe 2 /MoSe 2 2D heterobilayer, resolving the weak features of diffuse scattering and moiré superlattice structure without saturating the zero order peak. Enabled by the detector’s high frame rate, we show that a chopping technique provides diffraction difference images with signal-to-noise at the shot noise limit. Finally, we demonstrate that a fast detector frame rate coupled with a high repetition rate probe can provide continuous time resolution from femtoseconds to seconds, enabling us to perform a scanning ultrafast electron diffraction experiment that maps thermal transport in WSe 2 /MoSe 2 and resolves distinct diffusion mechanisms in space and time.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Time-Encoded Gamma-Ray Imaging Using a 3-D Position-Sensitive CdZnTe Detector Array

The gamma-ray response of thick pixelated CdZnTe detectors varies spatially but is relatively constant as a function of time. Detector irregularities arise from flaws in the material, electrode fabrication, and gaps between the detectors in an array. These nonuniformities generate artifacts in coded aperture images that can obscure a source of interest. This article presents the theory, design, and demonstration of a 3-D CdZnTe-based time-encoded imager. Experimental results show the gamma-ray images of point-like and extended 57 Co and HEU-metal sources formed using a spatially nonuniform 3-D CdZnTe detector array and moving coded aperture mask. Image signal-to-noise ratio (SNR) for a point source was within 10% of its statistical limit at 250k counts.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2019

MagMicro with Ultra-High Energy Resolution (FY19 Q4 Progress Report)

In Q4, we have completed the fabrication of the first set of four 32-pixel MMC gamma detector arrays (Figure 1.) After we had finally identified and corrected the problems with the deposition of the paramagnetic Ag:Er sensor in Q3, we deposited and patterned the insulators and adhesion layers and electroplated the Au absorber to complete the device.

42 ENGINEERING↗
DOE OSTI2024

A comparison of the neutron detection efficiency and response characteristics of two pixelated PSD-capable organic scintillator detectors with different photo-detection readout methods

Here, we characterize the performance of two pixelated neutron detectors: a PMT-based array that utilizes Anger logic for pixel identification and a SiPM-based array that employs individual pixel readout. The SiPM-based array offers improved performance over the previously developed PMT-based detector both in terms of uniformity and neutron detection efficiency. Each detector array uses PSD-capable plastic scintillator as a detection medium. We describe the calibration and neutron efficiency measurement of both detectors using a 137 Cs source for energy calibration and a 252 Cf source for calibration of the neutron response. We find that the intrinsic neutron detection efficiency of the SiPM-based array is (30.2 ± 0.9)%, which is almost twice that of the PMT-based array, which we measure to be (16.9 ± 0.1)%.

47 OTHER INSTRUMENTATION↗
DOE OSTI2018

Operation and performance of microhexcavity pixel detector in gas discharge and avalanche mode

The Microhexcavity Panel (μHex) is a novel gaseous micropattern particle detector comprised of a dense array of close-packed hexagonal pixels, each operating as an independent detection unit for ionizing radiation. It is a second generation detector derived from plasma panel detectors and microcavity detectors. The μHex is under development to be deployed as a scalable, fast timing (ns) and hermetically sealed gaseous tracking detector with high rate (> 100KHz / cm 2 ) capability. The devices reported here were fabricated as 16 × 16 pixel arrays of 2 mm edge-to-edge, 1 mm deep hexagonal cells embedded in a thin, 1.4 mm glass–ceramic wafer. Cell walls are metalized cathodes, connected to high voltage bus lines through conductive vias. Anodes are small, 457 μm diameter metal discs screen printed on the upper substrate. The detectors are filled with an operating gas to near 1 atm and then closed with a shut-off valve. They have been operated in both avalanche mode and gas discharge devices, producing mV to volt level signals with about 1 to 3 ns rise times. Operation in discharge mode is enabled by high impedance quench resistors on the high voltage bus at each pixel site. Results indicate that each individual pixel behaves as an isolated detection unit with high single pixel intrinsic efficiency to both βs from radioactive sources and to cosmic ray muons. Finally, continuous avalanche mode operation over several days at hit rates over 300 KHz / cm 2 with no gas flow have been observed. Measurements of pixel isolation, timing response, efficiency, hit rate and rate stability are reported.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2026

Gaia: segmented germanium detector for high-energy X-ray fluorescence and spectroscopic imaging

We present Gaia, a monolithic array of 96 high-purity germanium pixel detectors integrated with a custom low-noise application-specific integrated circuit (ASIC) and a field-programmable gate array (FPGA)-based data acquisition system. The sensor operates at ∼100 K using a commercial closed-cycle cryocooler, with the in-vacuum electronics thermally isolated from the cold finger to ensure thermal stability. The system demonstrates an average energy resolution of 711 eV at 122 keV, measured using a 57 Co source, and 253 eV at 5.89 keV, measured with 55 Fe across all channels. The readout architecture incorporates a high-performance FPGA paired with a dual-core ARM processor, forming a complete embedded Linux-based computing platform. Communication between the processor and FPGA is handled via memory-mapped I/O, and data are streamed over high-speed gigabit Ethernet. A full-scale 384-pixel Gaia detector, based on this 96-element module, is currently under fabrication.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Realistic full wave modeling of focal plane array pixels

Here in this paper we investigate full-wave simulations of realistic implementations of multifunctional nanoantenna enabled detectors (NEDs). We focus on a 2x2 pixelated array structure that supports two wavelengths of operation. We design each resonating structure independently using full-wave simulations with periodic boundary conditions mimicking the whole infinite array. We then construct a supercell made of a 2x2 pixelated array with periodic boundary conditions mimicking the full NED; in this case, however, each pixel comprises 10-20 antennas per side. In this way, the cross-talk between contiguous pixels is accounted for in our simulations. We observe that, even though there are finite extent effects, the pixels work as designed, each responding at the respective wavelength of operation. Finally, this allows us to stress that realistic simulations of multifunctional NEDs need to be performed to verify the design functionality by taking into account finite extent and cross-talk effects.

47 OTHER INSTRUMENTATION↗
DOE OSTI2022

The ultrafast pixel array camera system and its applications in high energy density physics

Diagnostics in high energy density physics, shock physics, and related fields are primarily driven by a need to record rapidly time-evolving signals in single-shot events. These measurements are often limited by channel count and signal degradation issues on cable links between the detector and digitizer. Here we present the Ultrafast Pixel Array Camera (UPAC), a compact and flexible detector readout system with 32 waveform-recording channels at up to 10 Gsample/s and 1.8 GHz analog bandwidth. The compact footprint allows the UPAC to be directly embedded in the detector environment. A key enabling technology is the PSEC4A chip, an eight-channel switch-capacitor array sampling device with up to 1056 samples/channel. The UPAC system includes a high-density input connector that can plug directly into an application-specific detector board, programmable control, and serial readout, with less than 5 W of power consumption in full operation. We present the UPAC design and characterization, including a measured timing resolution of ~20 ps or better on acquisitions of sub-nanosecond pulses with minimal system calibrations. Example applications of the UPAC are also shown to demonstrate operation of a solid-state streak camera, an ultrafast imaging array, and a neutron time-of-flight spectrometer.

47 OTHER INSTRUMENTATION↗
DOE OSTI2022

System Response Characterization for a d–t Neutron Radiography System

We report the system response of a pixelated associated particle imaging (API) neutron radiography system. The detector readout currently consists of a 2x2 array of organic glass scintillator detectors, each with an 8x8 array of optically isolated pixels that match the size and pitch of the ARRAYJ-60035-64P-PCB Silicon Photomultiplier (SiPM) array from SensL/onsemi with 6x6 mm 2 SiPMs. The alpha screen of the API deuterium-tritium neutron generator is read out with the S13361-3050AE-08 from Hamamatsu, which is an 8x8 array of 3x3 mm 2 SiPMs. Data from the 320 channel system is acquired with the TOFPET2-based readout system. We present the predicted imaging capability of an eventual 5x5 detector array, the waveform-based energy and pulse shape characterization of the individual detectors, and the timing and energy response from the TOFPET2 system.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2020

Automated co-adding and energy calibration of large array microcalorimeter data with zero sample knowledge

State-of-the-art microcalorimeter spectrometers now contain large detector arrays with hundreds of individual pixels. Each individual pixel outputs a unique and non-linear response with respect to deposited energy. This work describes a pattern-recognition algorithm to combine these responses into a single energy-calibrated histogram, referred to as co-adding pixels. Photo-peaks from different pixels are matched together based upon how well the match aligns the centroids and heights of neighboring peaks. This usually results in around 100 co-adding calibration points from 30 to 300 keV for a several day acquisition of plutonium items with masses between 0.5 and 10 grams. An additional algorithm energy-calibrates this co-added spectrum using the fluoresced K x-ray emissions from a tantalum absorber and inherent x-ray escape peaks from the tin absorbers. Both algorithms operate without knowledge of the source and are fully automated. This work presents results from the acquisitions of high and low burnup plutonium, 10% enriched uranium, a 153 Gd calibration source, and a 57 Co+ 166m Ho calibration source. In all measurements, resolution defined as the full-width at half-maximum (FWHM) of photo-peaks is preserved between the individual pixel and co-added spectra at around 65 eV for incident photon energies between 60 and 208 keV. The energy calibration algorithm is approximate and yields a calibration curve off by an average of around 200 eV for incident photon energies between 60 and 208 keV.

47 OTHER INSTRUMENTATION↗
DOE OSTI2020

Characterization of silicon drift detectors with electrons for the TRISTAN project

Sterile neutrinos are a minimal extension of the standard model of particle physics. A promising model-independent way to search for sterile neutrinos is via high-precision β-spectroscopy. The Karlsruhe tritium neutrino (KATRIN) experiment, equipped with a novel multi-pixel silicon drift detector focal plane array and read-out system, named the TRISTAN detector, has the potential to supersede the sensitivity of previous laboratory-based searches. In this work we present the characterization of the first silicon drift detector prototypes with electrons and we investigate the impact of uncertainties of the detector’s response to electrons on the final sterile neutrino sensitivity.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗