1. 3/2003 Rev 1 I.4.2 – slide 1 of 20 Part I Review of Fundamentals Module 4Sources of Radiation Session 2Cosmic Radiation Module I.4.2 IAEA Post Graduate Educational Course Radiation Protection and Safe Use of Radiation Sources

2. 3/2003 Rev 1 I.4.2 – slide 2 of 20 Introduction  Cosmic radiation from space will be discussed  Students will learn about cosmic radiation, cosmogenic radionuclides, variance of cosmic radiation with latitude and altitude, and exposure from cosmic radiation

3. 3/2003 Rev 1 I.4.2 – slide 3 of 20 Content  Cosmic radiation  Cosmogenic radionuclides  Radiation variance with latitude and altitude  Dose rates from cosmic radiation

4. 3/2003 Rev 1 I.4.2 – slide 4 of 20 Overview  Cosmic radiation and its health significance will be discussed  Cosmogenic radionuclides will be listed and described

5. 3/2003 Rev 1 I.4.2 – slide 5 of 20 Types of Cosmic Radiation  Primary cosmic radiation  Secondary cosmic radiation

6. 3/2003 Rev 1 I.4.2 – slide 6 of 20 Primary Cosmic Radiation  Made up of extremely high energy particles (up to 10 18 eV)  Composed mostly of protons or sometimes larger particles  Large percentage comes from outside solar system  Some comes from sun in form of solar flares

7. 3/2003 Rev 1 I.4.2 – slide 7 of 20 Secondary Cosmic Radiation  Produced by interaction of primary cosmic radiation with the atmosphere  Is what we actually receive here on Earth  Lower energy radiations in the form of photons, electrons, neutrons,and muons

8. 3/2003 Rev 1 I.4.2 – slide 8 of 20 Background Radiation Galactic radiation is a component of the background radiation on earth.

9. 3/2003 Rev 1 I.4.2 – slide 9 of 20 Background Radiation Cosmic radiation contributes to the background radiation on earth. The earth’s atmosphere provides shielding from most of the cosmic radiation.

10. 3/2003 Rev 1 I.4.2 – slide 10 of 20 Background Radiation The dose from cosmic radiation is reduced at lower altitude due to the additional shielding by the earth’s atmosphere.

11. 3/2003 Rev 1 I.4.2 – slide 11 of 20 Cosmogenic Radionuclides NuclideHalf-lifeSource Natural Activity 14 C 5730 yr Cosmic-ray interactions, 14 N(n,p) 14 C 0.22 Bq/g 3H3H3H3H 12.3 yr Cosmic-rayInteractions with N and O 1.2 x 10 -3 Bq/kg 7 Be 53.3 days Cosmic-rayInteractions with N and O 0.01 Bq/kg

12. 3/2003 Rev 1 I.4.2 – slide 12 of 20 Cosmic Ray Doses Subsonic Flight at 11 km Route Flight Duration (hrs) Dose per round trip (  Gy) Los Angeles – Paris 11.148 Chicago – Paris 8.336 New York - Paris 7.431 New York - London 7.029 Los Angeles - New York 5.219 Sydney - Acapulco 17.444

13. 3/2003 Rev 1 I.4.2 – slide 13 of 20 Cosmic Ray Doses Supersonic Flight at 19 km Route Flight Duration (hrs) Dose per round trip (  Gy) Los Angeles – Paris 3.837 Chicago – Paris 2.826 New York – Paris 2.624 New York – London 2.422 Los Angeles - New York 1.913 Sydney - Acapulco 6.221

14. 3/2003 Rev 1 I.4.2 – slide 14 of 20 Typical Cosmic Ray Dose Rates  4 x 10 -8 Sv/hr at ground level in Northeastern US  2 x 10 -7 Sv/hr at 4.6 km altitude  3 x 10 -6 Sv/hr at 16.8 km altitude

15. 3/2003 Rev 1 I.4.2 – slide 15 of 20 Natural Radiation Exposure Around the World

16. 3/2003 Rev 1 I.4.2 – slide 16 of 20 Cosmic Dose Rate Map of Switzerland

17. 3/2003 Rev 1 I.4.2 – slide 17 of 20 Effective Dose Equivalent to a Member of the Population of the United States Source Average Annual Effective Dose Equivalent  Sv mrem  Sv mrem Inhaled (radon and decay products) 2000200 Other Internbally Deposited Radionuclides 39039 Terrestrial Radiation 28028 Cosmic Radiation 2727 Cosmogenic Radioactivity 101 Rounded Total from Natural Sources 3000300 Rounded Total from Artificial Sources 60060 Total3600360

18. 3/2003 Rev 1 I.4.2 – slide 18 of 20 Sources of Radiation Exposure In the United States

19. 3/2003 Rev 1 I.4.2 – slide 19 of 20 Summary  Cosmic radiation was discussed  Cosmogenic radiouclides were listed and discussed  Radiation variance with latitude and altitude was described  Dose rates from cosmic radiation were discussed.

20. 3/2003 Rev 1 I.4.2 – slide 20 of 20 Where to Get More Information  Cember, H., Introduction to Health Physics, 3 rd Edition, McGraw-Hill, New York (2000)  Firestone, R.B., Baglin, C.M., Frank-Chu, S.Y., Eds., Table of Isotopes (8 th Edition, 1999 update), Wiley, New York (1999)  International Atomic Energy Agency, The Safe Use of Radiation Sources, Training Course Series No. 6, IAEA, Vienna (1995)