Presentation on theme: "RADIOPROTEZIONE DEGLI ASTRONAUTI DA RADIAZIONE COSMICA"— Presentation transcript:
1 RADIOPROTEZIONE DEGLI ASTRONAUTI DA RADIAZIONE COSMICA Gianfranco GrossiDipartimento di Scienze FisicheUniversità di Napoli Federico IIINFN - Sezione di Napoli
2 The places we will go if radiation doesn’t hold us back Earth and LEOThe Earth’s NeighborhoodAccessible Planetary SurfacesOuter PlanetsEarth-Moon L1TheMoonSun-Earth L2MarsAsteroids or Other Targets...Up to 180 daysL1Risk of cancer lethality(4 8) x 10-2 per SvL2Up to 100 days500 to 1000 days> 2000 daysDose - rate: 1 mSv/d2 mSv/d3 mSv/d
3 The problemLong-term interplanetary missions are planned in the XXI centuryCrews will be exposed to significant doses delivered by high-energy charged particles, in extreme conditions (stress, microgravity,..)Uncertainties on radiation risk estimates in deep space are between 400% and 1500%Uncertainty must be reduced for safehuman colonization of the solar system
4 “Best” shielding materials Projectile interactions per unit target mass:Ionization ~ Z/AFragmentation ~ A-1/3
5 HZE shieldingShielding of heavy ions is complicated by nuclear fragmentationProjectile fragmentation produces swift light ions and neutronsTarget fragmentation produces slow, densely ionizing ionsFragments have different Q than primary ions
7 The SHIELD experimentSHIELD started in 1999: 4 Italian research Institutes, NASA JSC, BNL, and NIRS (Japan)Goal: study of biological effects of heavy ions with shieldingResults of experimental studies can be used to benchmark the codesDifferent biological endpoints (CA, SV, DNA DSB) shield materials (LDPE, PMMA, C, Al, Pb) and thickness ( g/cm2), ion (H, C, Fe, Si, Ti) charge and energy ( GeV/n)Results presented here are relative to the induction of chromosomal aberrations in human lymphocytes exposed to 56Fe projectiles with different shields
8 Chromosomal aberrations measured by FISH in PCC from human lymphocytes Translocations involving chromosome 4 (left) and 2 (right). In light green chromosome 1, in red chromosome and in dark green chromosome 4
9 Nuclear fragmentation of AGS-BNL 56Fe beams 5 GeV/n 56Fe5 GeV/n 56Fe + 25 cm PMMACR39 nuclear plastic detector
10 CA / 1 GeV/n 56Fe-particle vs. shield thickness Effectiveness per Fe-particle incident on the shield is dependent on beam fragmentation, and is determined by combination of dose/particle and RBE-LET relationship
11 In-flight shielding test Best candidate shielding materials from accelerator-based research should eventually be tested onboard against the whole spectrum of trapped and galactic radiationESA has recently approved two experiments to study shielding in orbit using the detectors ALTEINO and MATROSHKA on International Space StationTwo experiments (ESCHILO and RADIS) will flight in to test the shielding effectiveness of new composite materials and, for comparison, polyethylene.
12 Shielding on ISS Sleep station outfitted with polyethylene and water Thin, flat panels are polyethylene shieldsStowage water packaging above the sleep station
13 ESCHILO (Esperimento di Schermatura in Low Orbit) Measurements of shielding on ISS (INFN, University Tor Vergata, Alenia Spazio, University Federico II)PI: Marco CasolinoDetector: ALTEINO on ISSShield: two multimaterial tiles divided into 4 sections
14 RADIS (Radiation Distribution) Large (23 Institutes, led by DLR, Germany) scientific collaboration to use MATROSHKA inside the ISS (from May 2005)University Federico II is supposed to provide shielding materials to cover MATROSHKA and measure the changes in dose, flux, radiation quality, etc. at various depths in the phantom.
15 Marco DuranteGiancarlo GialanellaGianfranco GrossiLorenzo MantiMariagabriella PugliesePaola Scampoli