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  • INSTRUMENTATION AND PHOTOGRAPHY  (3)
  • ATOMIC AND MOLECULAR PHYSICS  (1)
  • High Resolution Spectroscopy  (1)
  • SPACECRAFT INSTRUMENTATION  (1)
Collection
Keywords
Publisher
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  • 1
    Electronic Resource
    Electronic Resource
    Status of the Transient Gamma-Ray Spectrometer (1995)
    Springer
    Astrophysics and space science 231 (1995), S. 475-478 
    Details
    ISSN: 1572-946X
    Keywords: GRBs ; High Resolution Spectroscopy ; Solid State Detectors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The Transient Gamma-Ray Spectrometer (TGRS) was launched aboard the GGS/WIND spacecraft on November 1, 1994. After several deep space orbits (∼2 yrs) WIND will eventually be injected into a halo orbit around the Sun-EarthL 1 point. TGRS consists of a 215 cm3 high purityn-type Ge crystal which is kept at cryogenic temperatures by a passive radiative cooler. The energy range covered by the instrument is ∼25–8000 keV with an energy resolution of ∼2–3 keV. The primary task of TGRS is to perform high resolution spectroscopy of gamma-ray bursts and solar flares. Additional objectives are the study of transient x-ray pulsars and, using an on-board passive occulter, the long-term monitoring of sources such as the Crab and the Galactic Center. Since launch, TGRS has been performing exceedingly well, and all the important experiment parameters such as background levels, gain, and resolution have proven to be very stable. To date, TGRS has detected 27 GRBs and three solar flares. Preliminary analysis of our data also indicates that TGRS is indeed sensitive to sources such as the Crab and the Galactic Center.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00658674
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    Paper (German National Licenses)
    Fulltext
  • 2
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    Segmented Ge detector rejection of internal beta activity produced by neutron irradiation (1991)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Future Ge spectrometers flown in space to observe cosmic gamma-ray sources will incorporate segmented detectors to reduce the background from radioactivity produced by energetic particle reactions. To demonstrate the effectiveness of a segmented Ge detector in rejecting background events due to the beta decay of internal radioactivity, a laboratory experiment has been carried out in which radioactivity was produced in the detector by neutron irradiation. A Cf-252 source of neutrons was used to produce, by neutron capture on Ge-74 (36.5 percent of natural Ge) in the detector itself, Ge-75 (t sub 1/2 = 82.78 min), which decays by beta emission with a maximum electron kinetic energy of 1188 keV. By requiring that an ionizing event deposit energy in two or more of the five segments of the detector, each about 1-cm thick, the beta particles, which have a range of about 1-mm, are rejected, while most external gamma rays incident on the detector are counted. Analysis of this experiment indicates that over 85 percent of the beta events from the decay of Ge-75 are rejected, which is in good agreement with Monte Carlo calculations.
    Keywords: SPACECRAFT INSTRUMENTATION
    Type: IEEE Transactions on Nuclear Science (ISSN 0018-9499); 38; 218-220
    Format: text
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    NASA TECHNICAL REPORTS
  • 3
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    A position-sensitive germanium detector for gamma-ray astronomy (1984)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The critical problem in high-resolution cosmic gamma-ray spectroscopy in the energy range from 0.02 to 10 MeV is the limited spectral sensitivity of the detectors used. This results from the small effective area of the detectors and the high background noise due to induced radioactivity and scattering in the detectors' high-energy particle environment. The effective area can be increased by increasing the number of detectors, but this becomes prohibitive because of the size and expense of the resulting instrument. We have taken a new approach: a segmented large-volume germanium gamma-ray detector which can effectively discriminate against internal background yet maintain the high spectral resolution and efficiency of conventional coaxial Ge detectors. To verify this concept, a planar detector divided into two segments has been fabricated and laboratory measurements agree well with Monte Carlo calculations. A large coaxial detector which will be divided into five segments is being built using the techniques developed for the planar detector. Monte Carlo calculations show that the sensitivity (minimum detectable flux) of the segmented coaxial detector is a factor of 2-3 better than conventional detectors because of the reduction in the internal background.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: IEEE Transactions on Nuclear Science (ISSN 0018-9499); NS-31; 300-306
    Format: text
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  • 4
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    Radiation damage of germanium detectors (1978)
    In:  Other Sources
    Details
    Publication Date: 2019-06-27
    Description: Energetic particles can produce interstitial-vacancy pairs in a crystal by knocking the atoms from their normal positions. Detectors are unique among semiconductor devices in depending on very low concentrations of electrically active impurities, and also on efficient transport of holes and electrons over relatively large distances. Because the dense regions of damage produced by energetic particles may result in donors and/or acceptors, and also provide trapping sites for holes and electrons, detectors are very sensitive to radiation damage. In addition to these effects occurring within the detector, radiation may also change the characteristics of the exposed surfaces causing unpredictable effects on the detector leakage current. Radiation-induced surface degradation has rarely, if ever, been observed for germanium detectors. The possibility of minimizing hole trapping in charge collection by the use of a high-purity germanium coaxial detector configured with the p (+) contact on the coaxial periphery is discussed.
    Keywords: ATOMIC AND MOLECULAR PHYSICS
    Type: NASA. Goddard Space Flight Center Gamma Ray Spectry. in Astrophys.; p 473-478
    Format: text
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  • 5
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    Small area silicon diffused junction X-ray detectors (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The low-temperature performance of silicon diffused junction detectors in the measurement of low energy X-rays is reported. The detectors have an area of 0.04 sq cm and a thickness of 100 microns. The spectral resolutions of these detectors were found to be in close agreement with expected values, indicating that the defects introduced by the high-temperature processing required in the device fabrication were not deleteriously affecting the detection of low-energy X-rays. Device performance over a temperature range of 77 K to 150 K is given. These detectors were designed to detect low-energy X-rays in the presence of minimum ionizing electrons. The successful application of silicon-diffused junction technology to X-ray detector fabrication may facilitate the development of other novel silicon X-ray detector designs.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
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  • 6
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    Electronic considerations for externally segmented germanium detectors (1991)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: The dominant background source for germanium gamma ray detector spectrometers used for some astrophysics observations is internal beta decay. Externally segmented germanium gamma ray coaxial detectors can identify beta decay by localizing the event. Energetic gamma rays interact in the germanium detector by multiple Compton interactions while beta decay is a local process. In order to recognize the difference between gamma rays and beta decay events, the external electrode (outside of detector) is electrically partitioned. The instrumentation of these external segments and the consequence with respect to the spectrometer energy signal is examined.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: International Symposium on Gamma-Ray Line Astrophysics; Dec 10, 1990 - Dec 13, 1990; Paris; France
    Format: text
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