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New space and solar weather results obtained by R3DE instrument on EuTEF platform of ISS in 2008

New space and solar weather results obtained by R3DE instrument on EuTEF platform of ISS in 2008 Ts. Dachev 1 , B. Tomov 1 , Pl. Dimitrov 1 , Yu. Matviichuk 1 D . -P. Häder 2 , G. Horneck 3 and G. Reitz 3 1 Solar-Terrestrial Influences Laboratory, Sofia, Bulgaria, tdachev@bas.bg

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New space and solar weather results obtained by R3DE instrument on EuTEF platform of ISS in 2008

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  1. New space and solar weather results obtained by R3DE instrument on EuTEF platform of ISS in 2008 Ts. Dachev 1, B. Tomov1, Pl. Dimitrov1, Yu. Matviichuk1 D.-P. Häder2 ,G. Horneck3 and G. Reitz3 1Solar-Terrestrial Influences Laboratory, Sofia, Bulgaria, tdachev@bas.bg 2Friedrich-Alexander-Universität, Institut für Botanik und Pharmazeutische Biologie, Erlangen, Germany dphaeder@biologie.uni-erlangen.de DLR, Institute of Aerospace Medicine, Koln, Germany gerda.horneck@dlr.de, Guenther.Reitz@dlr.de

  2. Outlook • Instrumentation • Long-term GCR variations • First observation of Relativistic Electrons Precipitation at ISS • Characterization of the radiation environment by the shape and slope of the spectra • Asymmetries in SAA dose distribution • Conclusions ESWW5, Brussels, Belgium, 20 Nov. 2008

  3. InstrumentationThe EXPOSE facility supports long term in situ studies of microbes in artificial meteorites as well as of microbial communities from special ecological niches, such as endolithic and endoevaporitic ecosystems. EXPOSE is mounted on the European Technology Exposure Facility (EuTEF) located on the external plate of Columbus laboratory of International Space Station (ISS). The Radiation Risks Radiometer-Dosimeter (for European EXPOSE facility) (R3DE) inside the EXPOSE facility is an active, low mass and small dimensions device, which measure solar radiation in 4 channels and space ionizing radiation. The four-channel: UV-A (315-400 nm), UV-B (280-315 nm), UV-C (<280 nm) and Photosynthetic Active Radiation (PAR) (400-700 nm) filter dosimeter measure the solar UV irradiance in W/m2. The deposited energy spectra of the space ionizing radiation are measured by a Liulin type 256-channel spectrometer. The analysis of the spectra gives the total dose in Gy.hour-1 and the particle flux in cm2.s-1. Measurements of the UV and ionizing radiation parameters have 10 second time resolution and are transmitted by the ISS telemetry system to the ground since 20th of February 2008. ESWW5, Brussels, Belgium, 20 Nov. 2008

  4. R3DE instrument, which is apart of the EXPOSE facility is working continuously on the EuTEF platform of Columbus module on International space station since February 20th 2008 A close-up view of the Columbus laboratory Credits: ESA/NASA R3DE EuTEF EXPOSE The detector of R3DE instrument is shielded by less than 0.4 g/cm2material including: 1 mm aluminum + 0.1 mm cuprum +0.2 mm plastic. This allows direct hits on the detector by electrons with energies higher than 0.78, MeV and protons with energies higher than 15.8 MeV +Z ESWW5, Brussels, Belgium, 20 Nov. 2008

  5. The R3DE is an active, low mass (120 g) and small consumption (150 mW) device, which measure solar radiation in 4 channels and space ionizing radiation in 256 channels. Measurements have 10 s. time resolution and are transmitted by the ISS telemetry system to the ground since 20th of February 2008 ESWW5, Brussels, Belgium, 20 Nov. 2008

  6. R3D-B2/B3 instruments for ESA Biopan 5/6 facilities were successfully flown outside of Foton M2/M3 satellites in June 2005 and September 2007. The spectrometers are mutually developed with Prof. D.-P. Haeder, University of Erlangen, Germany Detector of 256 Channels LET spectrometer 4 Channels UV spectrometer UV-C channel UV-B channel UV-A channel PAR channel Size: 82x57x25 mm Weight: 129 g Consumption: 84mW Flash memory: 2 MB ESWW5, Brussels, Belgium, 20 Nov. 2008

  7. 12 mGy/h 29.4 mSv/h 10.3 mGy/h 27.2 mSv/h 7.38 mGy/h 16 mSv/h 6.14 mGy/h 14.6 mSv/h Long-term GCR variations obtained by comparison of doses obtained on different satellites Oulu neutron monitor data Solar minimum GCR doses in low earth orbit rise twice during the solar maximum, while neutron component on Earth surface rise up only with 10% ESWW5, Brussels, Belgium, 20 Nov. 2008

  8. Ulysses reveals global solar wind plasma http://www.nasa.gov/topics/solarsystem/features/ulyssesr-20080923.html ESWW5, Brussels, Belgium, 20 Nov. 2008

  9. GCR spectra observed at L values greater than 5 The doses created by GCR particles depends by the phase of the solar cycle and by the thickness of shielding before the detector. The neutron component is higher than 70% and well coincide with Phantom TORSO NASA TEPC 71% and DOSTEL 78% ESWW5, Brussels, Belgium, 20 Nov. 2008

  10. Sequence of Foton M3 60 seconds data with observations of other radiation belt relativistic electrons and SAA region On the energy-time 3D diagram the relativistic (>1 MeV) electron bursts are seen with red color bars in the upper panel and with black bars above 500 counts per minute in the lower panel. In this case the R3D-B3 spectra in Northern “N” and Sothern “S” hemisphere are relatively short and reach up to 50th channel; The 3 cases of crossing of inner radiation belt in the region of SAA are shown with labels “SAA”. The spectra in SAA are much wider reaching even the 256th channel. SAA SAA SAA S N S N S N S N S N S ESWW5, Brussels, Belgium, 20 Nov. 2008

  11. Example of observation of relativistic electrons with R3DE instrument on ISS on 28 February 2008 Relativistic (>1 MeV) electron bursts with maximum duration few minutes was observed by us first at the Foton M2 satellite behind 1.75 g/cm2 shielding. The maximmum dose observed is 304 mGy/h at 280 km altitude. At Foton M3 satellite behind 0.71 g/cm2 shielding the maximmum dose observed is 2314 mGy/h at 295 km altitude. At the EuTEF platform of Columbus module at ISS with R3DE instrument behind less than 0.4 g/cm2 shielding the maximmum dose is 19195 mGy/h at 361 km altitude. The flux of electrons reach 8363 cm-2 s-1. ESWW5, Brussels, Belgium, 20 Nov. 2008

  12. REP observed on ISS on 5th of March 2008 between 14:27and 14:46 hour ESWW5, Brussels, Belgium, 20 Nov. 2008

  13. Geographic positions of radiation sources selecting criteria ESWW5, Brussels, Belgium, 20 Nov. 2008

  14. Different radiation sources seen in Foton M3 data with lid open/closed When the lid of Biopan 6 is closed (~5.8 g/cm2) only protons from the region of SAA and GCR penetrate down to the detector of R3D-B3 ORB electrons When the lid is open (0.81 g/cm2) , because of lower shielding relativistic electrons with energy above 1 MeV start to penetrate to the detector also ORB SAA The GCR dose and flux for L>10 are higher (11.12 mGy/h) when lid is closed (11.04 mGy/h), because the secondary's and neutrons produced in the shield GCR ESWW5, Brussels, Belgium, 20 Nov. 2008

  15. Comparison of data obtained at Foton M3 by R3D-B3 instrument outside and Liulin-Photo instrument inside the capsule ESWW5, Brussels, Belgium, 20 Nov. 2008

  16. Main characteristics of the measurements by R3DE in geographic coordinates, in which the dose is more than 100 mGy/h in period 20 February- 20 March 2008 Descending data are clustered around evening UT, while ascending around morning UT. Small difference in the averaged altitude of SAA data in descending (353 km) and ascending (351 km) orbits can’t describe the large (with 56 mGy/h) averaged descending doses. Places of observations of relativistic electrons are separated in narrow latitudinal range equatorialward from magnetic poles. The calculated values of the incident proton energies in SAA region fall down from about 60 MeV at the west edge of the anomaly to 10 MeV at the east edge. Very high doses (Up to 19 mGy/h) in the regions equatorialward from magnetic poles are generated by relativistic (>1 MeV) electrons, which seems to be the first observation of them at ISS. ESWW5, Brussels, Belgium, 20 Nov. 2008

  17. + Foton M3, R3D-B3; Sept. 2007; D>50 mGy/h 0.81 g/cm2 + Foton M2, R3D-B2; June 2005; D>50 mGy/h 1.75 g/cm2 Geographic positions of radiation sources + ISS, R3DE; EuTEF, Feb.-Mar. 2008; D>100 mGy/h 0.4 g/cm2 ESWW5, Brussels, Belgium, 20 Nov. 2008

  18. ISS and Foton M3 global distributions of the averaged dose in pixels Long=10°, Lat=5° ESWW5, Brussels, Belgium, 20 Nov. 2008

  19. Comparison of the observed doses at 3 satellites High doses are regularly observed on Foton M2/M3 satellites in the Southern hemisphere at latitudes above the inclination oof ISS The REP on ISS are rare and very sporadic. Till the whole operation period of the R3DE instrument on ISS between February and July 2008 we have only 8 events when the doses are above 2000 μGy.h-1 ESWW5, Brussels, Belgium, 20 Nov. 2008

  20. Conclusions for REP If we will consider that the danger for the astronauts being on EVA relativistic electrons events are with dose above 500 μGy.h-1 than for the period 22 February 18 March 2008 we collect totally 132 10 seconds intervals, which is only 22 minutes. From other hand this observations are made in very low solar activity. The long period observations with SAMPEX satellite and others show increase of the REP observations when the solar activity is larger. This confirm another time the necessity of permanent active monitoring of the ISS radiation environment ESWW5, Brussels, Belgium, 20 Nov. 2008

  21. ORB SAA GCR Characterization by spectrumshape and slope Examples of the averaged spectra shapes and slopes for almost all available data. From below to up spectra are ordered in dependence of the absorbed dose. Lowest is from ground natural radiation = 0.12 while the highest = 9000 mGy/h is from relativistic electron measurements at ISS. ESWW5, Brussels, Belgium, 20 Nov. 2008

  22. Characterization of the type of radiation source by the shape and slope of the spectra Sky blue and light brown lines presents 2 different dose level spectra of the other belt relativistic electrons, which are observed till 2.5 MeV depsited energy. Further the spectrum coincide with the GCR spectrum. Blue (NW edge), black (Mean) and red (SE edge) lines presents 3 different positions spectra in the region of SAA. Green(L>3.5) and magenta (1.5<L) lines presents 2 different positions GCR spectra with respective doses of 11.4 and 1.59 mGy/h The change of slope at 6 MeV deposited energy is at the place where protons with energy 6 MeV are stopped in the detector ESWW5, Brussels, Belgium, 20 Nov. 2008

  23. Characterization of the type of incident ions by the shape of the spectra in the region of SAA Explanation of the shape of the spectrum with 2 maximums created by protons and helium ions. About 3% of all counts in SAA are created by Helium ions and protons falling at large angle toward the detector 536.6 Protons Hydrogen Ions for 10 s 16.6=3% Helium Ions for 10 s ESWW5, Brussels, Belgium, 20 Nov. 2008

  24. Comparison of dose asymmetries with theglobal distribution of the upper atmosphere neutral density ESWW5, Brussels, Belgium, 20 Nov. 2008

  25. Geometry of the R3DE detector against the predominateSAA proton drift from West to East ESWW5, Brussels, Belgium, 20 Nov. 2008

  26. Conclusions • Long term increase of the GCR flux and dose in the declining phase of the solar cycle was experimentally observed; • Relativistic electrons and doses produced by them was first observed on ISS; • The comprehensive analysis of the Liulin type instruments data and spectra gives opportunity to by characterized: - different radiation sources in space, in atmosphere and on ground; - the incident energy of the incoming to the detector protons; - the type of incoming to the detector ions; ESWW5, Brussels, Belgium, 20 Nov. 2008

  27. Thank you ESWW5, Brussels, Belgium, 20 Nov. 2008

  28. Zheng, Y., A. T. Y. Lui, X. Li, and M.-C. Fok Characteristics of 2–6 MeV electrons in the slot region and inner radiation belt, J. Geophys. Res., 111, A10204, doi:10.1029/2006JA011748, 2006. ESWW5, Brussels, Belgium, 20 Nov. 2008

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