Abstract
The Low Energy Charged Particle (LECP) experiment on the Voyager spacecraft is designed to provide comprehensive measurements of energetic particles in the Jovian, Saturnian, Uranian and interplanetary environments. These measurements will be used in establishing the morphology of the magnetospheres of Saturn and Uranus, including bow shock, magnetosheath, magnetotail, trapped radiation, and satellite-energetic particle interactions. The experiment consists of two subsystems, the Low Energy Magnetospheric Particle Analyzer (LEMPA) whose design is optimized for magnetospheric measurements, and the Low Energy Particle Telescope (LEPT) whose design is optimized for measurements in the distant magnetosphere and the interplanetary medium. The LEMPA covers the energy range from ∼10 keV to > 11 MeV for electrons and from ∼15 keV to ≳ 150 MeV for protons and heavier ions. The dynamic range is ∼0.1 to ≳ 1011 cm−2 sec−1 sr−1 overall, and extends to 1013 cm−2 sec−1 sr−1 in a current mode operation for some of the sensors. The LEPT covers the range ∼0.05 ≤ E ≳ 40 MeV/nucleon with good energy and species resolution, including separation of isotopes over a smaller energy range. Multi-dE/dx measurements extend the energy and species coverage to 300–500 MeV/nucleon but with reduced energy and species resolution. The LEPT employs a set of solid state detectors ranging in thickness from 2 to ∼2450 μ, and an arrangement of eight rectangular solid state detectors in an anticoincidence cup. Both subsystems are mounted on a stepping platform which rotates through eight angular sectors with rates ranging from 1 revolution per 48 min to 1 revolution per 48 sec. A ‘dome’ arrangement mounted on LEMPA allows acquisition of angular distribution data in the third dimension at low energies. The data system contains sixty-two 24-bit sealers accepting data from 88 separate channels with near 100% duty cycle, a redundant 256-channel pulse height analyzer (PHA), a priority system for selecting unique LEPT events for PHA analysis, a command and control system, and a fully redundant interface with the spacecraft. Other unique features of the LECP include logarithmic amplifiers, particle identifiers, fast (∼15 ns FWHM) pulse circuitry for some subsystems, inflight electronic and source calibration and several possible data modes.
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References
Alexander, A. F. O'D.: 1965 The Planet Uranus, Faber and Faber, London.
Alfvén, H. and Arrhenius, G.: 1976, Evolution of the Solar System, NASA SP-345, 1976.
Armstrong, T. P. and Krimigis, S. M.: 1973, Proc. 13th International Cosmic Ray Conference 2, 1504–1509.
Axford, W. I.: 1972 in Solar Wind, ed. C. P. Sonnett, P. J. Coleman, Jr. and J. M. Wilcox, NASA-SP-308, 609.
Brown, R. A.: 1973, Proc. Copernicus Symp. IV, IAU Symposium, No. 65, Torum, Poland.
Brown, L. W.: 1975, Astrophys. J. 198, L89, 1975.
Cameron, A. G. W.: 1973, Space Sci. Rev. 14, 383.
Chenette, D. L., Conlon, T. F., and Simpson, J. A.: 1974, J. Geophys. Res. 79, 3551.
Dolginov, Sh. Sh., Erashenko, E. G., and Zhuzgov, L. M.: 1972, Dokl. Akad. Nauk S.S.S.R. 207, 1296.
Duggal, S. P. and Pomerantz, M. A.: 1973, J. Geophys. Res. 78, 7205.
Fillius, R. W. and McIlwain, C. E.: 1974, J. Geophys. Res. 79, 3589.
Fisk, L. A., Kozlovsky, B., and Ramaty, R.: 1974, Astrophys. J. (Lett.), 190, L35.
Innanen, W. G. and Van Allen, J. A.: 1973, J. Geophys. Res. 78, 1019.
Kennel, C. F.: 1973, Space Sci. Rev. 14, 511.
Klecker, B., Hovestadt, D., Gloeckler, G., and Fan, C. Y.: 1975, Proc. 14th International Cosmic Ray Conference, Paper SP 2.2-8, Munich.
Krimigis, S. M., Kohl, J. W., and Armstrong, T. P.: 1975a, Geophys. Res. Lett. 2, 457.
Krimigis, S. M., Sarris, E. T., and Armstrong, T. P.: 1975b, Geophys. Res. Lett. 2, 561.
Mendis, D. A. and Axford, W. I.: 1974, Annual Rev. Earth Planet. Sci. 2, 419.
Ness, N. F., Behannon, K. W., Lepping, R. P., and Whang, Y. C.: 1975, J. Geophys. Res. 80, 2708.
Peletier, D. P., Gary, S. A., and Hogrefe, A. F.: 1977, IEEE Trans. Nucl. Sci., NS-24, 795.
Peletier, D. P.: 1975, IEEE Trans. Nucl. Sci. NS-22, 1.
Roelof, E. C. and Krimigis, S. M.: 1973, J. Geophys. Res. 78, 5375.
Roelof, E. C., Keath, E. P., Bostrom, C. O., and Williams, D. J.: 1976, J. Geophys. Res. 80, 2304.
Rosenbauer, H., Grunwaldt, H., Montgomery, M. D., Paschmann, G., and Sckopke, N.: 1975. J. Geophys. Res. 80, 2723.
Sarris, E. T., Krimigis, S. M., and Armstrong, T. P.: 1976, J. Geophys. Res. 81, 2341.
Siscoe, G. L.: 1975, Icarus, 24, 311.
Smith, E. J., Davis, L., Jr., Jones, D. E., Coleman, P. J., Jr., Colburn, D. S., Dyal, P., Sonett, C. P., and Fandsen, A. M. A.: 1974, J. Geophys. Res. 79, 3501.
Smith, E. J. and Wolfe, J. H.: 1976, Geophys. Res. Lett. 3, 137.
Thomsen, M. F. and Van Allen, J. A.: 1976, Astrophys. J. 206, 599.
Teegarden, B. J., McDonald, F. B., Trainor, J. H., Webber, W. R., and Roelof, E. C.: 1974, J. Geophys. Res. 79, 3615.
Wibberenz, G., Lanzerotti, L. J., and Venkatesan, D.: 1976, J. Geophys. Res. 81, 5807.
Williams, D. J.: 1975 in V. Formisano (ed.), The Magnetospheres of Earth and Jupiter, D. Reidel, Dordrecht, Holland, p. 161.
Williams, D. J. and Lyons, L. R.: 1974, J. Geophys. Res. 79, 4195.
Wolfe, J. H., Mihalov, J. D., Collard, H. R., McKibbin, D. D., Frank, L. A., and Intriligator, D. S.: 1974, J. Geophys. Res. 79, 3489.
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Krimigis, S.M., Armstrong, T.P., Axford, W.I. et al. The Low Energy Charged Particle (LECP) experiment on the Voyager spacecraft. Space Sci Rev 21, 329–354 (1977). https://doi.org/10.1007/BF00211545
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DOI: https://doi.org/10.1007/BF00211545