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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 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

A liquid xenon imaging telescope for 1-30 MeV gamma-ray astrophysics

A study of the primary scintillation light in liquid xenon excited by 241 Am alpha particles and 207 Bi internal conversion electrons are discussed. The time dependence and the intensity of the light at different field strengths have been measured with a specifically designed chamber, equipped with a CaF sub 2 light transmitting window coupled to a UV sensitive PMT. The time correlation between the fast light signal and the charge signal shows that the scintillation signals produced in liquid xenon by ionizing particles provides an ideal trigger in a Time Projection type LXe detector aiming at full imaging of complex gamma-ray events. Researchers also started Monte Carlo calculations to establish the performance of a LXe imaging telescope for high energy gamma-rays.

Aprile, Elena↗
NASA NTRS1989

A liquid xenon imaging telescope for 1-30 MeV gamma-ray astrophysics

A study of the primary scintillation light in liquid xenon excited by 241 Am alpha particles and 207 Bi internal conversion electrons are discussed. The time dependence and the intensity of the light at different field strengths have been measured with a specifically designed chamber, equipped with a CaF sub 2 light transmitting window coupled to a UV sensitive PMT. The time correlation between the fast light signal and the charge signal shows that the scintillation signals produced in liquid xenon by ionizing particles provides an ideal trigger in a Time Projection type LXe detector aiming at full imaging of complex gamma-ray events. Researchers also started Monte Carlo calculations to establish the performance of a LXe imaging telescope for high energy gamma-rays.

Aprile, Elena↗
NASA NTRS1999

In-Situ Spectrometry of Neutrons

High energy charged particles of extra-galactic, galactic and solar origin collide with spacecraft structures in Earth orbit outside the atmosphere and in interplanetary travel beyond the Earth's magnetosphere. These primaries create a number of secondary particles inside the structures that can produce a significant ionizing radiation environment. This radiation is a threat to long term inhabitants or travelers for space missions and produces an increased risk of cancer and DNA damage. The primary high energy cosmic rays and trapped protons collide with common spacecraft materials such as aluminum and silicon and create secondary particles inside structures that are mostly protons and neutrons. Charged protons are readily detected and instruments are already in existence for this task. Neutrons are electrically neutral and therefore much more difficult to measure and detect. These neutrons are reported to contribute 30-60% of the dose inside space structures and cannot be ignored. Currently there is no compact, portable and real time neutron detector instrumentation available for use inside spacecraft or on planetary surfaces where astronauts will live and work. We propose to design and build a portable, low power and robust neutron spectrometer that will measure the neutron spectrum from 10 KeV to 500 MeV with at least 10% energy resolution in the various energy intervals. This instrument will monitor the existing neutron environment both inside spacecraft structures and on planetary surfaces to determine the safest living areas, warn of high fluxes associated with solar storms and assist the NSBRI Radiation Effects Team in making an accurate assessment of increased cancer risk and DNA damage to astronauts. The instrument uses a highly efficient proportional counter Helium 3 tube at the lowest energy intervals where .equivalent damage factors for tissue are the highest (10 KeV-2 MeV). The Helium 3 tube may be shielded with a cadmium absorber to eliminate the much less damaging, but more prevalent, thermal and epithermal neutrons and to make the structure of the spectrum more accurate in the 20 KeV-2 MeV range; or a pair of tubes, one shielded and one unshielded, can be combined so that the difference in their counts yields the thermal neutron contribution. The spectrometer also uses a 5mm lithium drifted bulk silicon solid state detector in the medium energy range of 2-20 Mev and two standard silicon surface barrier detectors separated by tens of millimeters behind a I cm thick polyethylene moderator in a stack or telescope arrangement for the high energy neutrons (>20 MeV). In the medium and high energy regions equivalent damage factors are lower but hits from one or a small number of neutrons may prove to be important. The silicon detector systems for medium and high energy neutrons will discriminate against charged particles by using a plastic cesium iodide scintillator of an appropriate geometry monitored by a silicon PIN photodiode.

Maurer, Richard H.↗
NASA NTRS2001

ATIC Flight Data Processing

The first flight of the Advanced Thin Ionization Calorimeter (ATIC) experiment from McMurdo, Antarctica lasted for 16 days, starting on December 28, 2000. The ATIC instrument consists of a fully active 320-crystal, 960-channel Bismuth Germanate (BGO) calorimeter, 202 scintillator strips (808 channels) in 3 hodoscopes, interleaved with graphite target layers, and a 4480-pixel silicon matrix charge detector. We have developed an object-oriented data processing package based on ROOT. In this paper, we describe the data processing scheme used in handling the accumulated 45 GB of flight data. We discuss calibration issues, particularly the time-dependence of housekeeping information.

Ahn, H. S.↗
NASA NTRS1983

Nuclear Science Symposium, 29th, and Symposium on Nuclear Power, 14th, Washington, DC, October 20-22, 1982, Proceedings

High-energy radiation detectors suitable for balloon-borne or space-based radiation event studies are described. The employment of NaI(Tl) scintillator bars for gamma ray detection is outlined, and the development of a fluorescent gated gas-filled scintillation proportional counter is reported. A high throughput nondispersive hard X ray spectrograph with angular resolution for cosmic bursts, transients, and sources has been constructed. Features of a sealed high pressure xenon filled imaging proportional counter with a 30 sq cm sensitive area are explored. Finally, the various radiation effects on electronic circuitry in a space environment are defined, and an MOS dosimeter for assaying the cumulative radiation flux in a spacecraft due to ambient conditions is characterized.

Davis, W. D.↗
NASA NTRS1985

Modular detector for deep underwater registration of muons and muon groups

Registration and identification of muons and muon groups penetrating into the ocean depth, can be performed using a modular multilayer detector with high resolution bidimensional readout - deep underwater calorimeter (project NADIR). Laboratory testing of a prototype sensor cell with liquid scintillator in light-tight casing, testifies to the practicability of the full-scale experiment within reasonable expences.

Demianov, A. I.↗
NASA NTRS1985

Average features of the muon component of EAS or = 10(17) eV

Three 10 sq m liquid scintillators were situated at approximately 0 m, 150 m and 250 m from the center of the Haverah Park array. The detectors were shielded by lead/barytes giving muon detection thresholds of 317 MeV, 431 MeV and 488 MeV respectively. During part of the operational period the 431 MeV threshold was lowered to 313 MeV for comparison purposes. For risetime measurement fast phototubes were used and the 10% to 70% amplitude time interval was parameterized by T sub 70. A muon lateral density distribution of the form rho mu (R theta) = krho(500)0.94 1/R(1 + R/490)-eta has been fitted to the data for 120 m R 600 m and 0.27 (500) 2.55. The shower size parameter (500) is the water Cerenkov response at 500 m from the core of the extensive air showers (EAS) and is relatable to the primary energy. The results show general consistency.

Blake, P. R.↗
NASA NTRS1991

The Gamma Ray Observatory

The Gamma Ray Observatory (GRO), scheduled for launch by the Space Shuttle in April 1991, weighs 35,000 lbs and will offer 10 to 20 times better sensitivity than any previous gamma ray mission. The four instruments aboard GRO are described. The Burst and Transient Source Experiment (BATSE) will continuously monitor the entire sky for transient gamma-ray events using eight identical, wide-field detectors capable of measuring brightness variations lasting only milliseconds at energies from about 50,000 to 600,000 eV. The Oriented Scintillation Spectrometer Experiment (OSSE) will make comprehensive observations of discrete sources at energies from 100,000 to 10 million eV, where many radioactive elements have emission lines. The observatory's Imaging Compton Telescope will conduct a deep survey of the entire sky at gamma-ray energies between 1 and 30 MeV. The Energetic Gamma Ray Experiment Telescope will cover a broad high-energy spectral range, from about 20 million to 30 billion eV and conduct a sensitive all-sky survey with a wide field of view and good angular resolution.

Kniffen, Donald A.↗
NASA NTRS1993

The Oriented Scintillation Spectrometer Experiment - Instrument description

The Oriented Scintillation Spectrometer Experiment on the Arthur Holly Compton Gamma Ray Observatory satellite uses four actively shielded NaI (Tl)-CsI(Na) phoswich detectors to provide gamma-ray line and continuum detection capability in the 0.05-10 MeV energy range. The instrument includes secondary capabilities for gamma-ray and neutron detection between 10 and 250 MeV. The detectors have 3.8 deg x 11.04 deg (FWHM) fields of view defined by tungsten collimators. Each detector has an independent, single-axis orientation system which permits offset pointing from the spacecraft Z-axis for background measurements and multitarget observations. The instrument, and its calibration and performance, are described.

Johnson, W. N.↗
NASA NTRS2015

Calibration and Readiness of the ISS-RAD Charged Particle Detector

The International Space Station (ISS) Radiation Assessment Detector (RAD) is an intravehicular energetic particle detector designed to measure a broad spectrum of charged particle and neutron radiation unique to the ISS radiation environment. In this presentation, a summary of calibration and readiness of the RAD Sensor Head (RSH) - also referred to as the Charged Particle Detector (CPD) - for ISS will be presented. Calibration for the RSH consists of p, He, C, O, Si, and Fe ion data collected at the NASA Space Radiation Laboratory (NSRL) and Indiana University Cyclotron Facility (IUCF). The RSH consists of four detectors used in measuring the spectroscopy of charged particles - A, B, C, and D; high-energy neutral particles and charged particles are measured in E; and the last detector - F - is an anti-coincidence detector. A, B, and C are made from Si; D is made from BGO; E and F are made from EJ260XL plastic scintillator.

Rios, R.↗
NASA NTRS2004

The Energy Spectra of Heavy Nuclei Measured by the ATIC Experiment

ATIC (Advanced Thin Ionization Calorimeter) is a balloon-borne experiment to measure the spectra and composition of primary cosmic rays in the region of total energy from 100 GeV to near 100 TeV for Z from 1 to 26. ATIC consists of a pixelated silicon matrix detector to measure charge plus a fully active BGO calorimeter, to measure energy, located below a carbon target interleaved with three layers of scintillator hodoscope. The ATIC instrument had a second (scientific) flight from McMurdo, Antarctica from 12/29/02 to 1/18/03, yielding 20 days of good data. The GEANT 3.21 Monte Carlo code with the QGSM event generator and the FLUKA code with the DPMJET-II event generator were used to convert energy deposition measurements to primary energy. We present the preliminary energy spectra for the abundant elements C, O, Ne, Mg, Si and Fe and compare them with the results of the first (test) flight of ATIC in 2000-01 and with results from the HEAO-3 and CRN experiments.

Panov, A. D.↗
NASA NTRS1985

Air fluorescence detection of large air showers below the horizon

In the interest of exploring the cosmic ray spectrum at energies greater than 10 to the 18th power eV, where flux rates at the Earth's surface drop below 100 yr(-1) km(-2) sr(-1), cosmic ray physicists have been forced to construct ever larger detectors in order to collect useful amounts of data in reasonable lengths of time. At present, the ultimate example of this trend is the Fly's Eye system in Utah, which uses the atmosphere around an array of skyward-looking photomultiplier tubes. The air acts as a scintillator to give detecting areas as large as 5000 square kilometers sr (for highest energy events). This experiment has revealed structure (and a possible cutoff) in the ultra-high energy region above 10 o the 19th power eV. The success of the Fly's Eye experiment provides impetus for continuing the development of larger detectors to make accessible even higher energies. However, due to the rapidly falling flux, a tenfold increase in observable energy would call for a hundredfold increase in the detecting area. But, the cost of expanding the Fly's Eye detecting area will approximately scale linearly with area. It is for these reasons that the authors have proposed a new approach to using the atmosphere as a scintillator; one which will require fewer photomultipliers, less hardware (thus being less extensive), yet will provide position and shower size information.

Halverson, P.↗
NASA NTRS2003

Gas Scintillation Proportional Counters for High-Energy X-ray Astronomy

A focal plane array of high-pressure gas scintillation proportional counters (GSPC) for a balloon-borne hard-x-ray telescope is under development at the Marshall Space Flight Center. These detectors have an active area of approx. 20 sq cm, and are filled with a high pressure (10(exp 6) Pa) xenon-helium mixture. Imaging is via crossed-grid position-sensitive phototubes sensitive in the UV region. The performance of the GSPC is well matched to that of the telescopes x-ray optics which have response to 75 keV and a focal spot size of approx. 500 microns. The detector s energy resolution, 4% FWHM at 60 keV, is adequate for resolving the broad spectral lines of astrophysical importance and for accurate continuum measurements. Full details of the instrument and its performance will be provided.

Gubarev, Mikhail↗
NASA NTRS1992

A payload to evaluate photodiodes for the detection of soft and hard x rays in a space environment using a Get Away Special

We propose to use the Get Away Special (GAS) facility to evaluate P-intrinsic-N (PIN) detectors and avalanche photodiodes (APD's) for the detection of both solar and nonsolar soft and hard x rays. We would like to fly both types of silicon detectors for the direct detection of the x ray photons in the energy range from 1 to 30 keV with an energy resolution of about 1 keV. We would also like to use both types of photodiodes viewing CsI(Tl) scintillators to extend the energy range up to 1 MeV with -6 percent resolution at 660 keV. Solar flares would be detected with this instrumentation during periods of solar pointing providing high energy resolution spectra with high time resolution. Similar data would be obtained in the scanning mode on nonsolar transient and steady x ray sources with the same instrumentation. A commandable door over the detectors would be required to allow measurements to be made as low as 1 keV.

Desai, Upendra D.↗
NASA NTRS1985

Study of the energy spectrum of primary cosmic rays: EAS size fluctuations at a fixed primary energy

During the initial period of the Samarkand EAS array operations the showers were selected on the basis of charged-particle flux density, and during the subsequent periods the showers were selected on the basis of Cerenkov light flux density. This procedure made it possible to measure the shower energy, to estimate the EAS size fluctuations at a fixed primary energy, and to experimentally obtain the scaling factor K(Ne, Eo) from the EAS size spectrum to the primary energy spectrum. Six scintillators of area S = 2 sq m each were added to the array. The fluctuations of EAS sizes in the showers of fixed primary energies and the scaling factors K(Ne, Eo) were inferred from the data obtained. The showers with zenith angles 30 deg were selected. The EAS axis positions were inferred from the amplitude data of the scintillators. The primary energy Eo was determined by the method of least squares for the known EAS axis position using the data of the Cerenkov detector located at 80 to 150 m EAS axis. It is shown that the Cerenkov light flux fluctuations at 100 m from EAS axis, q sub 100, do not exceed 10% at a fixed EAS energy, so the parameter q sub 100 may be used to estimate the EAS-generating primary particle-energy.

Allev, N.↗
NASA NTRS1988

Spectral estimation of received phase in the presence of amplitude scintillation

A technique is demonstrated for obtaining the spectral parameters of the received carrier phase in the presence of carrier amplitude scintillation, by means of a digital phased locked loop. Since the random amplitude fluctuations generate time-varying loop characteristics, straightforward processing of the phase detector output does not provide accurate results. The method developed here performs a time-varying inverse filtering operation on the corrupted observables, thus recovering the original phase process and enabling accurate estimation of its underlying parameters.

Vilnrotter, V. A.↗
NASA NTRS1975

Certain problems in the development and design of scintillation and Cerenkov counters

The feasibility is examined of increasing the effectiveness of the scintillation and Cerenkov counters through improving light collection of the recorded radiation on the photoelectric cathode of the photomultiplier. An example of how to select a detector of the directional plexiglas Cerenkov counter is given. Also presented are experimentally obtained amplitude distributions during the recording of cosmic ray muons. The necessity to obtain agreement between the characteristic spectrum of the photocathode of the photomultiplier and the spectrum of the recorded radiation is stressed.

Chukin, V. S.↗