1. Radiation hazard to astronauts on Low-Earth Orbit Monika Puchalska (on behalf of the Polish MATROSHKA group) Department of Radiation Physics and Dosimetry Institute of Nuclear Physics Polish Academy of Sciences

2. Previous experiments inside ISS, 2001 effective dose quantity Radiation hazard The problem What does the personal dosemeter measure? ? MTR-2a MTR-1

3. Outline 1.Space project MATROSHKA 2.Methods 3.Results 4.Conclusions

4. International Contribution: 20 Institutes for MATROSHKA Science and Project Leader: G. Reitz, DLR ESA Project MATROSHKA project Project on the International Space Station (ISS)

5. The main goal: evaluation of the radiation hazard outside and inside ISS Effective dose [Sv] where:w T - tissue weighting factor D T - average dose in organ/tissue Q T - Quality factor Hiroshima & Nagasaki MATROSHKA project

6. 1.Phantom RANDO: tissue-equivalent material human skeleton embedded inside 2.Container simulating spacesuit MATROSHKA project

7. TLDs Total: 1631 measurement points 5373 TLDs (3140 TLDs from IFJ Kraków) 2.5 cm 3.Thermoluminescent detectors (TLDs) MATROSHKA project

8. Methods  Thermoluminescent (TL) method TL light emission Dose

9. Methods  Numerical phantom – developed at IFJ

10. MATROSHKA - Results  3D dose distribution MTR-1 – outside ISS MTR-2a – inside ISS

11.  Dose distribution  60% dose fall  30% dose fall from the most outer into the most inner measurement point MATROSHKA - Results MTR-1 – outside ISSMTR-2a – inside ISS

12. from the skin into the most outer measurement point  80% dose fall  10% dose fall MATROSHKA - Results  Dose distribution MTR-1 – outside ISSMTR-2a – inside ISS

13. + MATROSHKA - Results  Evaluation of the organ doses Spatial dose distributionNumerical phantom

14. MATROSHKA - Results Organ dose decreases for the inner structures  70% for outside exposure  20% for inside exposure Inside comparing to outside exposure: 5 times lower skin dose value  30% lower organ doses in the inner part of the body  Evaluation of the organ doses

15. MTR-1MTR-2a MATROSHKA - Results  Evaluation of the effective dose factor 1.3 MTR-1 – outside ISSMTR-2a – inside ISS

16. Personal dosemeter readout: 1.30 mSv/day Evaluated effective dose: 0.60 mSv/day Reason: low energy particles depositing their energy in the first few millimetres in the body whereas the important organs are located deeper and the personal dosemeter is located in front of the body MATROSHKA - Results  Effective dose versus the personal dosemeter readout MTR-1 - outside ISS Personal dosemeter readout: 0.58 mSv/day Evaluated effective dose: 0.45 mSv/day MTR-2a - inside ISS

17. Conclusions oFor the first time the radiation hazard to astronauts outside ISS was evaluated. oRadiation hazard to astronauts on Low-Earth Orbit outside ISS is higher by a factor 1.3 than inside ISS. oThe personal dosimeter more than two times overestimates the real radiation hazard outside ISS and by  30% inside ISS.

18. Thank you for your attention