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  • 1
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    Differential neutron energy spectra measured on spacecraft low Earth orbit (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Two methods for measuring neutrons in the range from thermal energies to dozens of MeV were used. In the first method, alpha-particles emitted from the (sup 6) Li(n.x)T reaction are detected with the help of plastic nuclear track detectors, yielding results on thermal and resonance neutrons. Also, fission foils are used to detect fast neutrons. In the second method, fast neutrons are recorded by nuclear photographic emulsions (NPE). The results of measurements on board various satellites are presented. The neutron flux density does not appear to correlate clearly with orbital parameters. Up to 50% of neutrons are due to albedo neutrons from the atmosphere while the fluxes inside the satellites are 15-20% higher than those on the outside. Estimates show that the neutron contribution to the total equivalent radiation dose reaches 20-30%.
    Keywords: ATOMIC AND MOLECULAR PHYSICS
    Type: High LET, Passive Space Radiation Dosimetry and Spectrometry; 6 p
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  • 2
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    A study of the radiation environment on board the space shuttle flight STS-57 (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: A joint NASA-Russian study of the radiation environment inside a SPACEHAB 2 locker on space shuttle flight STS-57 was conducted. The shuttle flew in a nearly circular orbit of 28.5 deg inclination and 462 km altitude. The locker carried a charged particle spectrometer, a tissue equivalent proportional counter (TEPC), and two area passive detectors consisting of combined NASA plastic nuclear track detectors (PNTD's) and thermoluminescent detectors (TLD's), and Russian nuclear emulsions, PNTD's, and TLD's. All the detector systems were shielded by the same shuttle mass distribution. This makes possible a direct comparison of the various dose measurement techniques. In addition, measurements of the neutron energy spectrum were made using the proton recoil technique. The results show good agreement between the integral LET spectrum of the combined galactic and trapped particles using the tissue equivalent proportional counter and track detectors between about 15 keV/micron and 200 keV/micron. The LET spectrum determined from nuclear emulsions was systematically lower by about 50%, possibly due to emulsion fading. The results show that the TEPC measured an absorbed dose 20% higher than TLD's, due primarily to an increased TEPC response to neutrons and a low sensitivity of TLD's to high LET particles under normal processing techniques. There is a significant flux of high energy neutrons that is currently not taken into consideration in dose equivalent calculations. The results of the analysis of the spectrometer data will be reported separately.
    Keywords: ATOMIC AND MOLECULAR PHYSICS
    Type: San Francisco Univ., High LET, Passive Space Radiation Dosimetry and Spectrometry; 24 p
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  • 3
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    Experimental and calculated LET distributions in the Cosmos-2044 biosatellite orbit (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: During the flight of the Cosmos-2044 biosatellite, joint U.S.S.R.-U.S.A. investigations of different characteristics of cosmic radiation (CR) in the near-Earth environment were carried out. The U.S. dielectric track detectors CR-39 and Soviet BYa- and BR-type nuclear photo-emulsions were used as detectors. The present work shows some results of experimental measurements of linear energy transfer (LET) spectra of CR particles obtained with the use of these detectors, which were placed both inside and outside the satellite. The LET spectra measurements with plastic detectors is composed of two parts: the measurement of galactic cosmos rays (GCR) particles, and of short-range particles. The contributions of these components to the total LET distribution at various thicknesses of the shielding were analyzed and the results of these studies are presented. Calculated LET spectra in the Cosmos-2044 orbit were compared with experimental data. On the basis of experimental and calculated values of the LET spectra, absorbed and equivalent CR doses were calculated. In the shielding range of 1-1.5 g cm(exp -2), outside the spacecraft, the photo-emulsions yielded 10.3 mrad d(exp -1) and 13.4 mrem d(exp -1) (LET greater than or equal to 40 MeV cm(exp -1)). Inside the spacecraft (greater than or equal to 10 g cm(exp -2) the photo-emulsions yielded 8.9 mrad d(exp -1) and 14.5 mrem d(exp -1).
    Keywords: ATOMIC AND MOLECULAR PHYSICS
    Type: San Francisco Univ., High LET, Passive Space Radiation Dosimetry and Spectrometry; 6 p
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  • 4
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    Neutron influences and energy spectra in the Cosmos-2044 biosatellite orbit (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Joint Soviet-American measurements of the neutron component of space radiation (SR) were carried out during the flight of the Soviet biosatellite Cosmos-2044. Neutron flux densities and differential energy spectra were measured inside and on the external surface of the spacecraft. Three energy intervals were employed: thermal (E(sub n) less than or equal to 0.2 eV), resonance (0.2 eV less than E(sub n) less than 1.0 MeV) and fast (E(sub n) greater than or equal to 1.0 MeV) neutrons. The first two groups were measured with U.S. (6)LiF detectors, while fast neutrons were recorded both by U.S. fission foils and Soviet nuclear emulsions. Estimations were made of the contributions to absorbed and equivalent doses from each neutron energy interval and a correlation was presented between fast neutron fluxes, measured outside the satellite, and the phase of solar activity (SA). Average dose equivalent rates of 0.018 and 0.14 mrem d(exp -1) were measured for thermal and resonance neutrons, respectively, outside the spacecraft. The corresponding values for fast neutrons were 3.3 (U.S.) and 1.8 (U.S.S.R.) mrem d(exp -1). Inside the spacecraft, a value of 3.5 mrem d(exp -1) was found.
    Keywords: ATOMIC AND MOLECULAR PHYSICS
    Type: High LET, Passive Space Radiation Dosimetry and Spectrometry; 4 p
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  • 5
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    Linear Energy Transfer (LET) spectra of cosmic radiation in low Earth orbit (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Integral linear energy transfer (LET) spectra of cosmic radiation (CR) particles were measured on five Cosmos series spacecraft in low Earth orbit (LEO). Particular emphasis is placed on results of the Cosmos 1887 biosatellite which carried a set of joint U.S.S.R.-U.S.A. radiation experiments involving passive detectors that included thermoluminescent detectors (TLD's), plastic nuclear track detectors (PNTD's), fission foils, nuclear photo-emulsions, etc. which were located both inside and outside the spacecraft. Measured LET spectra are compared with those theoretically calculated. Results show that there is some dependence of LET spectra on orbital parameters. The results are used to estimate the CR quality factor (QF) for the COSMOS 1887 mission.
    Keywords: SPACE RADIATION
    Type: San Francisco Univ., High LET, Passive Space Radiation Dosimetry and Spectrometry; 6 p
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  • 6
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    Linear energy transfer (LET) spectra of cosmic radiation in low Earth orbit (1990)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: Integral linear energy transfer (LET) spectra of cosmic radiation (CR) particles were measured on five Cosmos series spacecraft in low Earth orbit (LEO). Particular emphasis is placed on results of the Cosmos 1887 biosatellite which carried a set of joint U.S.S.R.-U.S.A. radiation experiments involving passive detectors that included thermoluminescent detectors (TLDs), plastic nuclear track detectors (PNTDs), fission foils, nuclear photo-emulsions, etc. which were located both inside and outside the spacecraft. Measured LET spectra are compared with those theoretically calculated. Results show that there is some dependence of LET spectra on orbital parameters. The results are used to estimate the CR quality factor (QF) for the Cosmos 1887 mission.
    Keywords: Aerospace Medicine
    Type: International Journal Of Radiation Applications And Instrumentation. Part D, Nuclear Tracks And Radiation Measurements (ISSN 0735-245X); 17; 2; 93-7
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  • 7
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    Differential neutron energy spectra measured on spacecraft in low Earth orbit (1990)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: Two methods for measuring neutrons in the range from thermal energies to dozens of MeV were used. In the first method, alpha-particles emitted from the 6Li(n,alpha)T reaction are detected with the help of plastic nuclear track detectors, yielding results on thermal and resonance neutrons. Also, fission foils are used to detect fast neutrons. In the second method, fast neutrons are recorded by nuclear photographic emulsions (NPE). The results of measurements on board various satellites are presented. The neutron flux density does not appear to correlate clearly with orbital parameters. Up to 50% of neutrons are due to albedo neutrons from the atmosphere while the fluxes inside the satellites are 15-20% higher than those on the outside. Estimates show that the neutron contribution to the total equivalent radiation dose reaches 20-30%.
    Keywords: Aerospace Medicine
    Type: International Journal Of Radiation Applications And Instrumentation. Part D, Nuclear Tracks And Radiation Measurements (ISSN 0735-245X); 17; 2; 87-91
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  • 8
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    Experimental and calculated LET distributions in the Cosmos-2044 biosatellite orbit (1992)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: During the flight of the Cosmos-2044 biosatellite, joint U.S.S.R.-U.S.A. investigations of different characteristics of cosmic radiation (CR) in the near-Earth environment were carried out. The U.S. dielectric track detectors CR-39 and Soviet BYa- and BR-type nuclear photo-emulsions were used as detectors. The present work shows some results of experimental measurements of linear energy transfer (LET) spectra of CR particles obtained with the use of these detectors, which were placed both inside and outside the satellite. The LET spectra measurement with plastic detectors is composed of two parts: the measurement of galactic cosmic rays (GCR) particles, and of short-range particles. The contributions of these components to the total LET distribution at various thicknesses of the shielding were analyzed and the results of these studies are presented. Calculated LET spectra in the Cosmos-2044 orbit were compared with experimental data. On the basis of experimental and calculated values of the LET spectra, absorbed and equivalent CR doses were calculated. In the shielding range of 1-1.5 g cm-2, outside the spacecraft, the photo-emulsions yielded 10.3 mrad d-1 and 27.5 mrem d-1 (LET 〉 or = 2 MeV cm-1) while the CR-39 yielded averages of 1.43 mrad d-1 and 13.4 mrem d-1 (LET 〉 or = 40 MeV cm-1). Inside the spacecraft (〉 or = 10 g cm-2) the photo-emulsions yielded 8.9 mrad d-1 and 14.5 mrem d-1.
    Keywords: Aerospace Medicine
    Type: International Journal Of Radiation Applications And Instrumentation. Part D, Nuclear Tracks And Radiation Measurements (ISSN 0735-245X); 20; 1; 143-7
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  • 9
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    Neutron fluences and energy spectra in the Cosmos-2044 biosatellite orbit (1992)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: Joint Soviet-American measurements of the neutron component of space radiation (SR) were carried out during the flight of the Soviet biosatellite Cosmos-2044. Neutron flux densities and differential energy spectra were measured inside and on the external surface of the spacecraft. Three energy intervals were employed: thermal (En 〈 or = 0.2 eV), resonance (0.2 eV 〈 En 〈 1.0 MeV) and fast (En 〉 or = 1.0 MeV) neutrons. The first two groups were measured with U.S. 6LiF detectors, while fast neutrons were recorded both by U.S. fission foils and Soviet nuclear emulsions. Estimations were made of the contributions to absorbed and equivalent doses from each neutron energy interval and a correlation was presented between fast neutron fluxes, measured outside the satellite, and the phase of solar activity (SA). Average dose equivalent rates of 0.018 and 0.14 mrem d-1 were measured for thermal and resonance neutrons, respectively, outside the spacecraft. The corresponding values for fast neutrons were 3.3 (U.S.) and 1.8 (U.S.S.R.) mrem d-1. Inside the spacecraft, a value of 3.5 mrem d-1 was found.
    Keywords: Life Sciences (General)
    Type: International Journal Of Radiation Applications And Instrumentation. Part D, Nuclear Tracks And Radiation Measurements (ISSN 0735-245X); 20; 1; 139-41
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