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The ALTEA and ALTEA-Shield experiments onboard the International Space Station

The ALTEA and ALTEA-Shield experiments onboard the International Space Station. L. Di Fino, M. Larosa, L. Narici, V. Zaconte University of Rome Tor Vergata. Scientific goals. ALTEA (Anomalous Long Term Effects on Astronauts) – PI: Prof. L. Narici

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The ALTEA and ALTEA-Shield experiments onboard the International Space Station

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  1. The ALTEA and ALTEA-Shield experiments onboard the International Space Station L. Di Fino, M. Larosa, L. Narici, V. Zaconte University of Rome Tor Vergata

  2. Scientificgoals • ALTEA (Anomalous Long Term Effects on Astronauts) – PI: Prof. L. Narici • Exposure of crew to space radiation poses one of the most significant hazards to space permanence. • A quest for understanding the risks for the Central Nervous System (CNS) during long permanence in space due to cosmic rays exposure. • Rationale: • anomalous Light Flash perceptions suggest that abnormal (though possibly transient) CNS functional states may result • Theoretically predicted by Tobias: Tobias C.A. 1952 J. Aviat. Med. 23 345 • First observed in 1969by Aldrin during Apollo-11 mission • Scientific strategy: • detailed measurement of radiation environment (DOSI) • measurement of transient/long-term functional effects of space environment and cosmic radiation on the CNS (CNSM) • survey of the radiation environment in space habitats (Survey) • test of shielding materials as countermeasures for CNS functional risks (Shield)

  3. ALTEA-Space facility • Particle Detector (Silicon Detector System) • 6 Silicon Detector Units (SDU) • 6 siliconplanes – 8x16 cm2, 380 mm thick • Geometricalfactor • SDU 230 cm2sr • SDS 1180 cm2sr • Detectable LET range: 3 - 800 KeV/mm DOSI – CNSM configurations • EEG, VSU, Pushbutton • DAU Surveyconfiguration

  4. ALTEA facilityonboard ISS Onboard ISS sinceJuly2006 2006-2007 ASI experiment 2009-2010 NASA-SRAG experiment 2010-2011 ESA experiment > 800 days of acquisition time > 1 billiontriggers

  5. ALTEA facilityonboard ISS

  6. ALTEA configurations DOSI (Dosimetry) Realtime measurement of radiation flux Total acquisition time 2006-2007: 224 days 2009-2010: 320 days ALTEA-Shield Survey Same as DOSI Different 3D holder Measurements in 4 different positions Total acquisition time 2006-2007: 281 days CNSM (Central Nervous System Monitoring) During a 90-minute session the astronaut wears EEG cap, slides under the SDS and signals LF perceptions 2006-2007: 7 sessions

  7. Realtime data ALTEA data are downloaded and analyzed in realtimeat the ALTEA User Home Base (UHB) at University of Rome Tor Vergata. A subset of ALTEA realtime data is publicly available through the NASA iNTEGRATED SPACE WEATHER ANALYSIS SYSTEM (iSWA) web application. http://iswa.ccmc.gsfc.nasa.gov

  8. Particle Rate • 6 SDUs, triggeredparticles • pole/equator and orbitprecessionmodulations • incrementduringpassages on the SAA

  9. Particleflux and ionabundances • Filter fast particles(ΔE ~ Z2) • Fit with a sum of Landau functions

  10. December 2006 Solar ParticleEvent

  11. IntegratedParticleFluxes and LET rates

  12. Particlefluxanisotropy Particle Flux LET rate

  13. UsLabsurvey • ALTEA-Shieldintegralfluxes (Preliminary) • Different positions and directions shows similarfluxesexcept for Position1-Y • For LET>50KeV/mm direction X shows a fluxattenuationasexpected any LET LET > 50 keV/um

  14. Conclusions The ALTEA-Space facility onboard ISS is used since 2006 in different experiments supported by all major space agencies. • It delivered a detailed measurement of the radiation environment inside the UsLab, several measurements on astronauts and a survey of the radiation environment in different positions. • A strong anisotropy (up to a factor 3 in LET) was found when considering high LET particles (LET > 50) coming from different directions. • The second step of ALTEA-Shield (Shield) experiment is planned in 2012 to test the effectiveness of different shielding materials and thicknesses • A collaboration with Jaxa is under consideration for further measurements on astronauts At last… we are looking for students!

  15. Thankyou for yourattention!

  16. METHOD: use ALTEA as single detector Particle flux anisotropy in raw angular flux distribution is masked by the SDUs’ angular acceptance. A Montecarlo simulation (PHITS) of an isotropic flux was used to obtain each SDU angular acceptance. To use ALTEA as a single detector we sum all the SDUs to obtain the angular acceptance of the whole ALTEA detector - R(q,j).

  17. Results: Poles Spectra Particle Flux LET rate

  18. Results: Equator Spectra Particle Flux LET rate

  19. Results: SAA Spectra Particle Flux LET rate

  20. ALTEA - CNSM 7 sessionieseguite, 3 Astronauti (1 sess + 2 sess + 4 sess) Numero di LF segnalati nelle sessioni CNSM Rate di particelle passanti per l’occhio (part/min)

  21. ALTEA - CNSM Particella candidata (Z~3) alla generazione di un LF

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