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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 793 records · Page 44
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Light-tight Skipper-CCDs for X-Ray Detection in Space

Skipper Charge-Coupled Devices (skipper-CCDs) are pixelated silicon detectors with deep sub-electron resolution. Their radiation hardness and capability to reconstruct energy deposits with unprecedented precision make them a promising technology for space-based X-ray astronomy. In this scenario, optical and near-infrared photons may saturate the sensor, distorting the reconstructed signal. We present a light-tight shield for skipper-CCDs to suppress optical backgrounds while preserving X-ray detection efficiency. We deposited thin aluminum layers on the CCD surface using an e-beam evaporator and evaluated their blinding performance across wavelengths from 650 to 1000 nm using a monochromator, as well as the X-ray transmission using an 55 Fe source. We find that 50 and 100 nm layers provide >99.6% light suppression, with no efficiency loss for 5.9 and 6.4 keV X-rays. In addition, we used Geant4 simulations to extend these results to a broader energy range and quantify the efficiency loss for different aluminum thicknesses. Results show that thin aluminum coatings are an effective, low-cost solution for optical suppression in skipper-CCDs intended for X-ray detection and space instrumentation.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

Start-to-end self-consistent simulation of the UEM beamline

Addressing the preliminary design review report of the ultrafast electron microscope (UEM), start-to-end self-consistent simulations were carried out to explore fundamental aspects affecting the resolution (space-charge effects, energy spread, shot-to-shot energy jitter, contrast formation, etc.). The electron beam energy spread in the single-shot mode and the effective energy spread in the accumulation mode, equivalent to the convolution of the single-shot energy spread and shot-to-shot energy jitter, have been identified as the ultimate limits of the instrument resolution. A full self-consistent simulation from the photocathode to the detector is being performed using the GPT code to find out what resolution can be achieved. Preliminary results of the start-to-end simulations are reported in this note and the plan of further simulations is presented.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Assessment of PHDS Fulcrum40h and Ortec Detective-X High Purity Germanium (HPGe) Detector System Performance

This report provides a summary of measurement results used to compare the performance of the PHDS Fulcrum40h and Ortec Detective-X High Purity Germanium (HPGe) detector systems. Specifically, the measurement data collected was used to assess each detector system for gamma efficiency and resolution, gamma angular response and efficiency for an in-situ surface distribution, neutron efficiency, gamma pulse-pileup response, and gamma to neutron crosstalk.

42 ENGINEERING↗
DOE OSTI2025

Direct reactions with the AT-TPC

Direct reactions are crucial tools for accessing properties of the atomic nucleus. Fundamental and exotic phenomena such as collective modes, pairing, weakbinding effects and evolution of single-particles energies can be investigated in peripheral collisions between a heavy nucleus and a light target. The necessity of using inverse kinematics to reveal how these structural properties change with isospin imbalance renders direct reactions a challenging technique when using the missing mass method. In this scenario, Active Target Time Projection Chambers (AT-TPC) have demonstrated an outstanding performance in enabling these types of reactions even under conditions of very low beam intensities. The AT-TPC of the Facility for Rare Isotope Beams (FRIB) is a next generation multipurpose Active Target. When operated inside a solenoidal magnet, direct reactions benefit from the measurement of the magnetic rigidity that enables particle identification and the determination of the excitation energy with high resolution without the need of auxiliary detectors. Additionally, the AT-TPC can be coupled to a magnetic spectrometer improving even further its spectroscopic investigation capability. In this contribution, we discuss inelastic scattering and transfer reaction data obtained via the AT-TPC and compare them to theory. In particular, we present the results for the 14 C(p,p′) and 12 Be (p,d) 11 Be reactions. For 14 C, we compare the experimental excitation energy of the first 1 – excited state with coupled-cluster calculationsbased on nuclear interactions from chiral effective field theory and with available shell-model predictions. For 12 Be, we determine the theoretical spectroscopic factors of the 12 Be (p,d) 11 Be transfer reaction in the shell modeland compare them to the experimental excitation spectrum from a qualitative standpoint.

active target↗
NASA NTRS1972

Techniques in balloon X-ray astronomy.

Since the first balloon observation of the Crab Nebula balloon data have provided much information on the positions, spectra, time variability and pulsed nature of localized sources, and on the spectrum and isotropy of diffuse galactic and universal components. Measurements are limited to energies above about 20 keV by atmospheric attenuation at 2 to 3 g/sq cm depth and to below several hundred keV by detector sensitivity. Detectors usually consist of large-area Na I or Cs I scintillation counters with anticoincidence collimators for rejection of charged particles and scattered X-rays. Proportional counters are occasionally used at lower energies and solid-state detectors are used where extreme energy resolution is important. The instruments require a pointing capability on the order of 1.0 to 0.1 deg, depending on the collimator aperture. Digital data is either recorded on board or telemetered using a PCM technique.

Peterson, L. E.↗
NASA NTRS1973

Space application of SEC vidicons - The OSO 7 coronagraph.

An externally occulted Lyot coronagraph employing a digitized SEC vidicon detection system is a prime experiment aboard the NASA Orbiting Solar Observatory 7 (OSO 7). Continuing daily operation since the 29 September 1971 launch has produced more than 2200 pictures of the solar white light corona covering the region between 3 R and 10 R. Important advantages of the SEC vidicon in this application are its ability to integrate an electron image and store it for long periods prior to readout. Special applications of digital techniques are employed in stepping and pulsing the readout electron beam, thereby realizing the detector's inherent qualities of high resolution and large dynamic range.

Brueckner, G.↗
NASA NTRS1973

Muon capture rates on O-16 leading to bound states of N-16.

A low-energy spectrum of gamma-rays following muon capture in O-16 was obtained with a high-resolution 1 cu cm Ge(Li) detector. The graph of the spectrum shows the separation of contaminant peaks from the 120 keV N-16 line. It is pointed out that there is a large discrepancy between the capture rate obtained in the investigation and results reported by Deutsch et al. (1969).

Kane, F. R.↗
NASA NTRS1985

The gamma-ray telescope Gamma-1

French and Soviet specialists have designed and built the gamma-ray telescope GAMMA-1 to detect cosmic gamma rays above 50 MeV. The sensitive area of the detector is 1400 sq cm, energy resolution is 30% at 300 MeV, and angular resolution 1.2 deg at 300 MeV (and less than 20' arc when a coded aperture mask is used). Results on calibration of the qualification model and Monte-Carlo calculations are presented.

Akimov, V. V.↗
NASA NTRS1983

Airborne Imaging Spectrometer - An advanced concept instrument

The Airborne Imaging Spectrometer (AIS) is a multispectral infrared imaging instrument utilizing a 32- x 32-element mercury-cadmium-telluride detector array to achieve high spatial resolution. A novel optical design provides high spectral resolution, and, in conjunction with the 32-element spatial resolution, makes optimal use of the capabilities of the area array. The experiment requirements and the details of instrument design, implementation, and calibration are presented. The superior resolution, accuracy, and data acquisition rate of this sensor/instrument concept for reconnaissance and geophysical survey is detailed and plans for upgrading/improving the instrument and future applications of this design concept are discussed.

Labaw, C.↗
NASA NTRS1985

Large-scale mapping of the Galaxy by IRAS

The Infrared Astronomical Satellite (IRAS), launched Jan. 25, 1983, has conducted a high-sensitivity, high-resolution all-sky photometric survey at wavelengths of 12, 25, 60, and 100 microns in the infrared. One of the data products to be developed from the survey is a map of the entire Milky Way within latitude limits of 10 degrees at a resolution of 4 arcmin. The dc-coupled, extremely stable detector system permits mapping with reliable information at all spatial scales larger than the map resolution. The extremely high sensitivity of the IRAS instrument for the detection of interstellar material in the survey mode is illustrated in terms of visual extinction and dust and gas column densities.

Gautier, T. N., III↗
NASA NTRS1986

Cosmic X-ray physics

The analysis of the beryllium-filtered data from Flight 17.020 was completed. The data base provided by the Wisconsin diffuse X-ray sky survey is being analyzed by correlating the B and C band emission with individual velocity components of neutral hydrogen. Work on a solid state detector to be used in high resolution spectroscopy of diffuse or extend X-ray sources is continuing. A series of 21 cm observations was completed. A paper on the effects of process parameter variation on the reflectivity of sputter-deposited tungsten-carvon multilayers was published.

Mccammon, D.↗
NASA NTRS1986

Search for volatiles in the surface of icy satellites

It is proposed to measure the reflectance spectra of the icy satellites of Jupiter, Saturn and Uranus in the spectral region 1.8 to 2.4 micrometers. These observations use the new Cooled Grating Array Spectrometer using a 32-element InSb photodiode array detector and produce spectra of higher resolution and precision than any data yet obtained; the ultimate scientific objective is to search for the signatures of methane clathrate, ammonium hydroxide or carbon monoxide clathrate (compounds predicted to exist on icy surfaces in the outer solar system by several theories of formation of these bodies) in the region of the spectrum where water ice has a relative maximum in reflectance. At the very least, these data will allow upper limits to be placed on the amount of these chemical species that can be present. The specific targets is Europa, Ganymede, Enceladus, Ariel and Titania, bodies that have the highest probability of having some or all of these volatiles on their surface according to current formation models.

Brown, R. H.↗
NASA NTRS1987

'Marginal' BY Draconis stars

Spectroscopic observations of 52 dK-dM stars, obtained at 640-665 nm (with spectral resolution 70-90 pm) using CCD detectors on the coude-feed telescope at KPNO since 1982, are reported. Data for four stars found to have diluted absorption or weak emission above continuum at H-alpha are presented in tables and spectra and discussed in detail. These objects (Gliese numbers 256, 425A, 900, and 907.1) are shown to be 'marginal' BY Dra stars, single objects of age 2.5-3 Gyr with activity and rotational velocity (3-5 km/s) between those of normal dM stars and those of true BY Dra stars. An explanation based on evolution from the BY Dra stage through marginal BY Dra to inactive dM is proposed.

Bopp, Bernard W.↗
NASA NTRS1991

A ubiquitous absorption feature in the X-ray spectra of BL Lacertae objects

The paper presents the broadband (0.5-20-keV) X-ray spectra of five X-ray bright BL Lac objects observed with the Einstein Observatory Solid State Spectrometer (SSS) and Monitor Proportional Counter (MPC) detectors. The combination of moderate energy resolution and broad spectral coverage makes it possible to confirm the presence of an absorption feature at an energy of 650 eV in the BL Lac object PKS 2155-304, originally reported by Canizares and Kruper (1984) based on higher resolution Einstein Objective Grating Spectrometer (OGS) data.

Madejski, Greg M.↗
NASA NTRS1990

IRAS observations of extended dust envelopes around evolved stars

Deconvolved IRAS profiles, with resolution 2-3 time better than detector sizes 1.5 and 3 arcmin at 60 and 100 microns, are presented for a number of evolved stars with extended emission. These include VY UMa, Mu Cep, S Sct, U Hya, Y CVn, U Ant, alpha Ori, Y Pav, UU aur, IRC + 10216, RZ Sgr, and R Lyr. Simple models suggest that extended IRAS emission results from stars which greater mass loss rates in the past, rather than from stars with large current mass loss rates.

Hawkins, George↗
NASA NTRS1992

Intensity distribution of the x ray source for the AXAF VETA-I mirror test

The X-ray generator for the AXAF VETA-I mirror test is an electron impact X-ray source with various anode materials. The source sizes of different anodes and their intensity distributions were measured with a pinhole camera before the VETA-I test. The pinhole camera consists of a 30 micrometers diameter pinhole for imaging the source and a Microchannel Plate Imaging Detector with 25 micrometers FWHM spatial resolution for detecting and recording the image. The camera has a magnification factor of 8.79, which enables measuring the detailed spatial structure of the source. The spot size, the intensity distribution, and the flux level of each source were measured with different operating parameters. During the VETA-I test, microscope pictures were taken for each used anode immediately after it was brought out of the source chamber. The source sizes and the intensity distribution structures are clearly shown in the pictures. They are compared and agree with the results from the pinhole camera measurements. This paper presents the results of the above measurements. The results show that under operating conditions characteristic of the VETA-I test, all the source sizes have a FWHM of less than 0.45 mm. For a source of this size at 528 meters away, the angular size to VETA is less than 0.17 arcsec which is small compared to the on ground VETA angular resolution (0.5 arcsec, required and 0.22 arcsec, measured). Even so, the results show the intensity distributions of the sources have complicated structures. These results were crucial for the VETA data analysis and for obtaining the on ground and predicted in orbit VETA Point Response Function.

Zhao, Ping↗