Questions. 1. What kind of radiation dominates the first phase of radiation emission from a nuclear fireball?

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1 Questions 1. What kind of radiation dominates the first phase of radiation emission from a nuclear fireball? 2. What is the ignition temperature of wood? 3. What fuels a firestorm?

2 Natural Radioactivity Most of it was generated in neutron driven nucleosynthesis processes in previous star generations and implemented on earth during the early phasesoftheformationofthe solar system (Hadean phase).

Nuclear decay of the accumulated actinides, e.g.

3 Earth s internal heat source Heavy elements accumulate in the core of earth and to a lesser extend in the earth s crust. Nuclear decay of the accumulated actinides, e.g. Uranium U and Thorium Th isotopes release energy and serve as internal heat source keeping the outer core of earth in a hot and liquid state.

4 Temperature conditions Temperature within Earth increases with depth. Highly viscous or molten rock at temperatures between 650 to 1,200 C (1,202 to 2,192 F) is expected at depths of 50 to 60 miles. The temperature at the Earth's inner core/outer core boundary, around 2,200 miles deep, is estimated to be 5650 ± 600 K. The heat content of the earth is J. Isotope Heat release [W/kg isotope] Half life [years] Mean mantle concentration [kg isotope/kg] Heat release [W/kg] 238 U U Th K In the continental crust, the decay of natural radioactive isotopes is the main source of geothermal heat. The crust is abundant in lower density minerals but also contains large concentrations of heavier minerals such as uranium. Because of this, it holds the largest global reservoir of radioactive elements found in the Earth. Especially in layers closer to Earth's surface, naturally occurring isotopes are enriched in the granite and basaltic rocks.

5 First Signatures Geo Neutrinos Kamioka Mine 1000 m Neutrino production associated with decay of radioactive _ elements _ e.g. 234 Th 234 Pa U+ + Neutrinos/anti neutrinos are measured in underground detector arrays such as Kamland (Kamioka, Japan and Borexino (Gran Sasso, Italy)

6 Natural decay chains Sequence of alpha decay and beta decay from 232 Th and 238 U to 208 Pb and 206 Pb Enrichment of Uranium and Thorium in specific geological stone or mineral configurations, such as granite or shale.

$fraction of$ has 92

7 Uranium distribution Primarily 238 U (99.27%) but with a certain fraction of 235 U (0.72%). Uranium has 92 protons, 238 U has 146 neutrons, 235 U has 133 neutrons!

8 Radioactivities in rocks

9 Radon Exposure Radon is noble gas, its radioactive components 220, 222 Rn are produced as part of the natural decay chain. Radon gas cannot be chemically bound, it diffuses into soil or bedrock and into basements of buildings where it accumulates and can be inhaled, causing lung cancer by subsequent alpha emission, breaking DNA bonds

10 Cosmogenic Radioactivity Bombardment of the atmosphere by intense high energetic particle radiation (electrons, protons, and heavy elements) produced and accelerated by the magnetic field of the sun (solar activity cycle) and by distant cataclysmic events such as supernovae.

11 Origin and nature of cosmic rays Cosmic rays cover a wide energy range, depending on the source (sun to distant supernova). Rays cause spallation effects in the atmosphere generating a secondary radiation flux.

Tritium is produced by fast neutron s (>4 MeV) e.g.

N(n,p) 14 Ccauses a specific 14 C activity level in the

12 Tritium is produced by fast neutron s (>4 MeV) e.g. by the 14 N(n,t) 12 C process (plus other reactions). It forms superheavy water HTO or T 2 O. The global inventory prior to nuclear bomb tests was estimated to 26 MCi or TBq. Slow neutron capture on the natural nitrogen 14 N isotope, 14 N(n,p) 14 Ccauses a specific 14 C activity level in the atmosphere of 38kCi/y or 1400 TBq/y. This 14 C is distributed to living organisms by the biological carbon cycle (human 0.1 Ci or 3.7 kbq).

13 Cosmogenic radioactive isotopes

14 Cosmic ray induced mutation? Cosmic ray triggers mutation processes by affecting the molecular structure or sequence of DNA sections, causing the mutations which drive evolution of life.

High Altitude Maximum exposure is near stratospheric altitude because of interaction probability of incoming ray with atmospheric particles.

15 High Altitude Maximum exposure is near stratospheric altitude because of interaction probability of incoming ray with atmospheric particles. At lower altitudes sea level to mountain level you experience an increase in cosmic ray exposure roughly doubling with every 1500 m. High exposure to mountain populations, air personnel, and frequent flyers.

16 Anthropogenic radioactivity Mining Traffic and exhaust Nuclear energy Nuclear bomb tests Nuclear medicine

17 Uranium Mining Underground mining in Namibia Surface mining in Utah

18 Coal mines

19 Building materials

20 Oil drilling waste

21 Agriculture & Fertilizers Primarily from fertilizers based on phosphate rock (mostly from Florida) with high uranium content. Distribution by subsequent plant up take and absorption into animal and human food chain. Annually ~30 million tons of phosphate used for fertilizer production containing about 1000 Ci or 37 TBq of radioactivity ( 226 Ra).

22 Nuclear Energy According to the Energy Information Administration of the U.S. Department of Energy, from 2006 to 2030, world net energy consumption is projected to increase by 44 percent.

24 After Chernobyl Reactor core Accumulated activity Daily release

25 Nuclear Medicine Imaging techniques PET: 18 F SPECT: 99 Tc Radiation Treatment External Beam Therapy Brachytherapy

26 Nuclear Imaging Blood flow with radiopharmaceuticals Imaging software and analysis Gamma Camera SPECT & PET Isotopes & Isomers Pharmaceuticals Tumor mapping & visualization by radioactive isotope accumulation. Imaging system development

PET with Fludeoxyglucose (18F) for 3d whole-body scans Exposure of 16mCi or 5.

27 PET with Fludeoxyglucose (18F) for 3d whole-body scans Exposure of 16mCi or Bq = 590 MBq Chernobyl level 3.7 MBq/m2 Problem is subsequent water contamination with radioactive pharmaceuticals

28 Radiation Treatment Brachytherapy Gamma therapy Neutron therapy Heavy ion therapy

29 Developments

Radioactivity. Lecture 11 The radioactive Earth

Radioactivity. Lecture 11 The radioactive Earth Radioactivity Lecture 11 The radioactive Earth The Violent Beginning Most of the planet s radioactivity was generated in neutron driven nucleosynthesis processes in previous star generations and implemented