2. Nuclear Chemistry

3. Do Now What do you think nuclear chemistry is?

4. Nuclear Chemistry- the branch of chemistry involving reactions in which nuclei change.

5. Radioactivity One of the pieces of evidence for the fact that atoms are made of smaller particles came from the work of Marie Curie (1876-1934). She discovered radioactive decay, the spontaneous disintegration of some elements into smaller pieces and the element radium.

6. Her death near Sallanches, Savoy, in 1934 was from aplastic anemia, almost certainly due to exposure to radiation, as the damaging effects of ionising radiation were not yet known, and much of her work had been carried out in a shed with no safety measures. She had carried test tubes containing radioactive isotopes in her pocket and stored them in her desk drawer, remarking on the pretty blue-green light the substances gave off in the dark.SallanchesSavoyaplastic anemiaradiation ionising radiation

7. Nuclear Symbols Element symbol Mass number, A (p + + n o ) Atomic number, Z (number of protons p + ) 235 92 U Nucleons= protons and neutrons Nuclide= name of an atom in nuclear chemistry Remember that the nucleus is comprised of the two nucleons, protons and neutrons. The number of protons is the atomic number. The number of protons and neutrons together is effectively the mass of the atom.

8. Nuclear Reactions vs. Normal Chemical Changes Nuclear reactions involve the nucleus. The nucleus opens, and protons and neutrons are rearranged. The opening of the nucleus releases a tremendous amount of energy that holds the nucleus together – called binding energy. “Normal” Chemical Reactions involve electrons and their bonding, not protons and neutrons

9. Radioactive decay= the spontaneous disintegration of an unstable nucleus into a slightly lighter nucleus, accomplished by the emission of particles, electromagnetic radiation, or both. Transmutation = a change in the identity of a nucleus as a result of a change in the number of protons. Radioactive decay is a Natural transmutation = radioactive decay of unstable elements

10. The stability of a nuclide depends on the ratio of neutrons to protons. Most nuclides are stable. These nuclei tend to decay by alpha emission. Some stable elements have isotopes that are unstable. These are called radioisotopes. In order to achieve stability, radioactive nuclides undergo radioactive decay # protons = # neutrons

11. Nuclear Stability Decay will occur in such a way as to return a nucleus to the band (line) of stability. The most stable nuclide is Iron-56 If atomic number Z > 83, the nuclide is radioactive (unstable)

12. Stable Nuclei Nuclei above this belt have too many neutrons. They tend to decay by emitting beta particles.

13. Stable Nuclei Nuclei below the belt have too many protons. They tend to become more stable by positron emission or electron capture.

14. Radioactive Series Large radioactive nuclei cannot stabilize by undergoing only one nuclear transformation. They undergo a series of decays until they form a stable nuclide (often a nuclide of lead).

15. Isotopes Not all atoms of the same element have the same mass due to different numbers of neutrons in those atoms. There are three naturally occurring isotopes of uranium: –Uranium-234 –Uranium-235 –Uranium-238 Different mass numbers indicate different number of neutrons

16. Do Now What do you think radioactive decay is? What types of particles do you think are involved?

17. Types of Radiation Alpha (ά) – a positively charged helium isotope *we usually ignore the charge because it involves electrons, not protons and neutrons Beta (β - ) – an electron Gamma (γ) – pure energy; called a ray rather than a particle

18. Other Nuclear Particles Neutron Positron – a positive electron Proton – usually referred to as hydrogen-1 Any other elemental isotope

19. Types of Radioactive Decay Alpha Decay Beta Decay Positron Emission Gamma Radiation

20. Radiation is emitted from: microwaves visible light radio waves TV waves ultraviolet light

21. 1. Alpha Decay- Type of Radioactive Decay An alpha particle is a helium nucleus 2 protons and 2 neutrons (+ charge) Result of alpha decay at end of reaction the nuclides’: –Atomic mass decreases by 4. –Atomic number decreases by 2.

23. Practice Problem The nuclide 220 Fr undergoes alpha decay. 87 What is produced? 220 Fr  216 At + 4 He 8785 2

24. Practice Problem What radioactive isotope is produced in the following bombardment of boron? 10B + 4He ? + 1n 5 2 0 13 N 7

25. http://www.ndt- ed.org/EducationResources/HighSchool/R adiography/Graphics/Flash/transmut.swfhttp://www.ndt- ed.org/EducationResources/HighSchool/R adiography/Graphics/Flash/transmut.swf

26. 2. Beta Decay Type of Radioactive Decay Negative charge An electron Result of beta decay at end of reaction the nuclides’: –Mass # remains the same –Atomic number increases by 1

28. Practice Problem The nuclide 32 P undergoes beta (-) decay. 15 What is the result? 32 P  32 S+ 0 e 15 16 -1

29. Practice Problem Write the reactant that produces the daughter nucleus 14 N by beta decay. 7 14 C  14 N + 0 e 6 7 -1

30. http://www.ndt- ed.org/EducationResources/HighSchool/R adiography/Graphics/Flash/transmut.swfhttp://www.ndt- ed.org/EducationResources/HighSchool/R adiography/Graphics/Flash/transmut.swf

31. 3. Positron emission Type of Radioactive Decay + charge Has mass of electron Result of positron emission at end of reaction the nuclides’: –Atomic number decreases by 1 –Mass stays the same Positron emission converts a proton to a neutron 207

32. 4. Gamma Radiation Type of Radioactive Decay High energy waves emitted from a nucleus as it changes from the excited state to the ground state.

34. Gamma rays

35. Deflection of Decay Particles Opposite charges attract each other. Like charges repel each other.

36. Nuclear decay http://www.mhhe.com/physsci/chemistry/e ssentialchemistry/flash/radioa7.swfhttp://www.mhhe.com/physsci/chemistry/e ssentialchemistry/flash/radioa7.swf Simulation: http://phet.colorado.edu/en/simulation/nucl ear-fission http://phet.colorado.edu/en/simulation/nucl ear-fission

38. Summary of the most common forms of radiation ParticleMassChargeSymbolPenetrating power Alpha4 amu+2Low Beta0 amuModerate Positron0 amu+1Moderate Gamma0 amuNonehigh

39. Table O

40. Do Now What are half lives? How do half lives relate to radioactive decay?

41. Half Life= time it takes for ½ the atoms in the radioactive sample to decay.

42. Half-life Concept

43. Half-Life Decay of 20.0 mg of 15O. What remains after 3 half-lives? After 5 half-lives?

45. Graph showing the size and the activity of a sample of oxygen-15 nuclei. The shapes of the two curves are the same. They both halve at regular intervals.

47. Sample Half-Lives

48. Radioisotope Half-Life Hydrogen-3 12.3 years Carbon-14 5730 years Phosphorus-32 14.3 days Phosphorus-33 25.3 days Sulfur-35 87.6 days Iodine-125 60.1days

49. See Table N Selected Radioisotopes –Half life (in seconds, minutes, hours, days or years –Decay mode (use with Table O)

50. To find the amount of a sample remaining after a certain amount of days: 1. Find the half-life on Table N. 2. Make a table with 2 columns: time and mass 3. Begin your table with zero time.

51. How much of a 100 gram sample of iodine- 131 will remain after 24 days? TIMEMASS 0 days100 g 8 days50 g 16 days25 g 24 days12.5 g

52. M&M activity Using a one minute half life, calculate the quantity of M&Ms every five minutes for your sample. Record your data on the back page of your notes. Graph your data too!

53. Calculating Half-lives Number of half-lives = time elapsed (t) half- life (T) Fraction remaining= (1/2) t/T Mass remaining = original mass X fraction remaining

54. Practice Problem Number of half-lives = time elapsed (t) half- life (T) Phosphorous-32 has a half life of 14.3 days. Determine how many half-lives elapse during 57.2 days. How many milligrams remain if you start with 4.0mg? TimeMass

55. Practice Problem The half life of radon-22 is 3.824 days. After what time will one-fourth of a given amount of radon remain? TimeMass

56. Practice Problem A sample contains 16 mg of polonium-218. After 12 minutes, the sample will contain 1.0 mg of polonium-218. What is the half life of polonium-218? # half lives = t T TimeMass

57. Practice Problem The half life of I-123 is 13 hr. How much of a 64 mg sample of I-123 is left after 39 hours?

58. Do Now Describe the changes that occur from alpha, beta (+/-), and neutron decay. –Alpha decay decreases atomic mass by 4 and decreases atomic number by 2 –Beta (-) decay increases atomic number by 1 –Beta (+) or Positron decay decreases atomic number by 1 –Neutron decay does not change atomic number, but mass number decrease atomic mass by 1

59. Table N Review Determine the nuclide formed from the radioactive decay of Plutonium-239. 239 Pu  4 He + 235 U 94 2 92

60. See Table N Selected Radioisotopes –Half life (in seconds, minutes, hours, days or years –Decay mode (use with Table O)

61. Balancing Nuclear Reactions In the reactants (starting materials – on the left side of an equation) and products (final products – on the right side of an equation) –Atomic numbers must balance and –Mass numbers must balance Use a particle or isotope to fill in the missing protons and neutrons

62. Balancing Nuclear Equations  A reactants =  A products  Z reactants =  Z products 235 + 1 = 142 + 91 + 3(1) 92 + 0 = 56 + 36 + 3(0)

63. Balancing Nuclear Equations 226 = 4 + ____ 222 88 = 2 + __ 86 Atomic number 86 is radon, Rn Rn

64. Balancing Nuclear Equations 235 + 1 = 139 + 2(1) + ____ 95 39 92 + 0 = 53 + 2(0) + ____ 39 95 Atomic number 39 is yttrium, Y Y

65. Do Now Recall the definition of a transmutation. –Transmutation = a change in the identity of a nucleus as a result of a change in its number of protons

66. Transmutations a change in the identity of a nucleus as a result of a change in its number of protons. Natural transmutation = radioactive decay of unstable elements –Ex: Artificial transmutation = a change brought about by bombarding the nucleus of a stable atom with high energy particles, such as neutrons, protons, alpha particles.

67. Neutrons can easily penetrate the nucleus of an atom because they have no charge. Alpha particles and protons are repelled by the nucleus but with great quantities of energy they can penetrate the nucleus. They can gain this energy in particle accelerators.

68. How can YOU tell the difference between a natural and artificial transmutation? –The natural transmutation will have ONE reactant (a radioactive nucleus). –The artificial transmutation will have TWO reactants (a fast moving particle and a target nucleus).

69. FISSION REACTIONS A very heavy nucleus splits into more stable nuclei of intermediate mass. ENORMOUS amounts of energy are released! Each neutron produced will bombard another uranium-238. The generation of nuclear power is an example of Artificial transmutation.

70. Nuclear Fission & POWER Currently about 103 nuclear power plants in the U.S. and about 435 worldwide. 17% of the world’s energy comes from nuclear.

71. The Fission Reaction of Uranium-235

72. http://www.visionlearning.com/library/flash_viewer.php?oid=2391&mid=59

73. Chain reaction Chain reaction = one in which the material that starts the reaction is also one of the products and can start a new reaction. Fission reactions produce the energy used in nuclear power plants. These are CONTROLLED fission reactions (the number of neutrons produced is controlled).

74. This fuel lasts longer than fossil fuels and there is no pollution produced. BUT because the fuels and products of fission are radioactive, they pose a health hazard to people who may accidentally be exposed.

75. Nuclear Reactors- fission reactions occur In nuclear reactors the heat generated by the reaction is used to produce steam that turns a turbine connected to a generator.

76. Nuclear Reactors The reaction is kept in check by the use of control rods. These block the paths of some neutrons, keeping the system from reaching a dangerous supercritical mass.

77. Controlled fission reaction

78. http://chimge.unil.ch/En/nuc/1nuc14.htm Uncontrolled chain reaction http://www.visionlearning.com/library/flash _viewer.php?oid=3602&mid=59http://www.visionlearning.com/library/flash _viewer.php?oid=3602&mid=59 Controlled and uncontrolled

80. What is done with the products of fission (nuclear energy)? Solid radioactive wastes (strontonium-90 and cesium-137) are sealed in containers and stored underground in isolated areas. Low-level radioactive wastes are diluted and released into the atmosphere. Gaseous radioactive wastes (radon- 222,krypton-85,nitrogen-16) are stored until they decay to safe levels and released into the atmosphere.

81. Geiger Counter Used to detect radioactive substances

83. Effects of Radiation

84. Deliberate poisoning using radioactive materials On November 23, 2006, Alexander Litvinenko died due to suspected deliberate poisoning with polonium-210.Alexander Litvinenkopoisoningpolonium His is the first case of confirmed death due to such a cause, although it is also known that there have been other cases of attempted assassination such as in the cases of KGB defector Nikolay Khokhlov and journalist Yuri Shchekochikhin where radioactive thallium was used. Nikolay KhokhlovYuri Shchekochikhinthallium Before poisoning After poisoning

85. August 8, 1945: Smoke rises 60,000 feet above the Japanese port of Nagasaki, after the second atomic bomb ended World War II. Long-term studies of atomic-bomb survivors at Hiroshima and Nagasaki are key evidence on the health impact of low-level radiation. Photo: NARANARA

86. The city was unbelievably devastated. Of its 90,000 buildings, over 60,000 were demolished. Another bomb was assembled at Tinian Island on August 6. On August 8, Field Order No.17 issued from the 20th Air Force Headquarters on Guam called for its use the following day on either Kokura, the primary target, or Nagasaki, the secondary target. Three days after Hiroshima, the B-29 bomber, "Bockscar" piloted by Sweeney, reached the sky over Kokura on the morning of August 9 but abandoned the primary target because of smoke cover and changed course for Nagasaki.

87. The Danger of Radiation The radiation caused alterations in the blood, destroyed the bone marrow's ability to produce blood and also seriously damaged the liver and other internal organs. Numerous people sustained fatal injuries as a result. Within about 2 kilometers of the hypocenter, high-levels of residual radioactivity remained on the ground for about 2 weeks after the actual explosion. Therefore, some who came to the area soon afterwards developed symptoms of radiation sickness and died.

88. Lost Hair Hiroko (then 18) and her six-year old brother were on the first floor of their home, only 800 meters from ground zero, when the bomb's blast wrecked the house. They managed to get outside the house. She had thirty-seven injuries, but her little brother was hardly hurt at all. Her brother remained healthy and active until August 21, when suddenly his temperature rose rapidly. Most of his hair came out and sometime later, convulsed with vomiting, her little brother died. Not long afterward, the mother was combing Hiroko's hair, and it too came out easily. At the time people often said that the loss of hair meant death was near. Hiroko resigned herself to the same fate as her brother. But Hiroko made a remarkable recovery. Gradually her hair grew back. Though she still suffered some atomic aftereffects, she was married in 1947. She had to have several surgical operations. But she tries always to live courageously, saying, "I must do my best to make up for my brother's short life."

89. Black Rain From around 9 a.m. black rain covered a wide area from the hypocenter to the north-west. It rained heavily for one hour or more in some areas. Since the rain contained a lot of black soot which was produced by the terrific sea of fire, it was called "black rain", oily and sticky. Furthermore, it contained radioactive elements produced by the fission of uranium. Exposed to the rain, many people developed symptoms of the atomic bomb diseases and died.

90. Keloids on Arms The heat rays of the atomic bomb struck the human body and produced burns. At the same time, radioactivity injured the inner tissues of the skin and formed keloids on the surface of the skin. After seeming to heal, the scars left by the burns swelled up. This type of swelling is called a keloid. Most keloids developed in 1946 and 1947, and most commonly in teenagers. At present, most keloids have flattened out but are still recognizable as scars.

91. The atomic shadow The shadows of the parapets were imprinted on the road surface of the Yorozuyo Bridge, 1/2 a mile south-south-west of the hypocenter. It is one of the important clues for establishing the location of the epicenter. October. Photo: the U.S. Army. WWW MuseumWWW Museum

92. Do Now Describe fission and its uses. What does it mean to fuse something?

93. FUSION Two or more light nuclei combine to form a single nucleus of greater mass. EVEN MORE ENERGY THAN FISSION! The sun’s energy is believed to be the result o four hydrogen nuclei combining at very high temperatures to make a helium nucleus. In order to get the nuclei to fuse, extremely high temperatures and pressures are needed. –Excessive heat cannot be contained –Attempts at “cold” fusion have FAILED. –“Hot” fusion is difficult to contain.

94. Fusion The mass of the products is less than the mass of the reactants, because some mass is converted into energy (Famous equation: E = mc 2 ) http://www.visionlearning.com/library/flash_viewer.php?oid=2747&mid=59

95. Nuclear Fusion Fusion would be a superior method of generating power. –The good news is that the products of the reaction are not radioactive. –The bad news is that in order to achieve fusion, the material must be in the plasma state at several million kelvins. –Tokamak apparati like the one shown at the right show promise for carrying out these reactions. –They use magnetic fields to heat the material.

96. Review: Nuclear Fission and Fusion Fusion: Combining two light nuclei to form a heavier, more stable nucleus. Fission: Splitting a heavy nucleus into two nuclei with smaller mass numbers.

97. There are two big problems that scientists and engineers face when trying to create a fusion reaction. –(1) Fusion can only occur at very high temperatures, such as 100 million degrees. –(2) The fused atoms must be held together long enough for the reaction to complete. Commercial applications of fusion, for both space and everyday power sources will provide us with a safe, clean, inexhaustible energy source.

98. Atomic bomb vs. Hydrogen bomb Atomic bomb = uses a fission reaction –Ex: WWII in Hiroshima and Nagasaki, Japan Hydrogen bomb = uses a fusion reaction –More dangerous and destructive, because almost unlimited energy released!

99. Nuclear Transformations –Nuclear transformations can be induced by accelerating a particle and colliding it with the nuclide. –These particle accelerators are enormous, having circular tracks with radii that are miles long.

100. USES AND DANGERS OF RADIOISOTOPES 1. Radioactive dating 2. Chemical tracers 3. Medical applications

101. 1. Radioactive Dating Radioactive isotopes can be used to date previously living materials or non-living materials. Carbon-14 = used to date fossils Uranium-238 = decays to Pb-206 used to date minerals

102. Radiocarbon Dating Radioactive C-14 is formed in the upper atmosphere by nuclear reactions initiated by neutrons in cosmic radiation 14 N + 1 o n ---> 14 C + 1 H The C-14 is oxidized to CO 2, which circulates through the biosphere. When a plant dies, the C-14 is not replenished. But the C-14 continues to decay with t 1/2 = 5730 years. Activity of a sample can be used to date the sample.

103. The Laetoli Walkway contains 54 hominid footprints pointing north along two parallel tracks. Mary Leakey considered these footprints her most important discovery during six decades of research in East Africa. Radioactive dating places these footprints at 3.59 to 3.75 million years old. At the time of their discovery, the earliest known human footprints were left by Neandertals some 80,000 years ago.

104. 2. Chemical Tracers Tracer = any radioisotope used to follow the path of a material in a system. Radioisotopes behave the same as stable isotopes. Reactions in living systems can be traced using carbon-14.

105. 3. Medical applications Radioisotopes with very short half-lives are administered to patients for diagnostic purposes. Examples: –Technetium-99 is used to determine the location of brain and other cancerous tumors. –Iodine-131 is used to diagnose thyroid problems. –Radium and cobalt-60 are used in cancer therapy. –Intense gamma radiation can be used to kill bacteria on foods (Cobalt-60 and cesium-137 can destroy anthrax)

106. Nuclear Medicine: Imaging Thyroid imaging using Tc-99m

107. Normal PET Scan

108. Positron Emission Tomography- PET Scan

109. Food Irradiation Food can be irradiated with gamma rays from 60 Co or 137 Cs. Irradiated milk has a shelf life of 3 mo. without refrigeration. USDA has approved irradiation of meats and eggs.

110. THE END

114. alpha particle radiation beta particle radiation neutrons gamma rays x-rays

115. Nuclear Reactions Alpha emissionAlpha emission Note that mass number (A) goes down by 4 and atomic number (Z) goes down by 2. Nucleons (nuclear particles… protons and neutrons) are rearranged but conserved

116. Alpha Radiation Limited to VERY large nucleii.

117. Alpha Decay Alpha production (  ): an alpha particle is a helium nucleus Alpha decay is limited to heavy, radioactive nuclei

118. Nuclear Reactions Beta emissionBeta emission Note that mass number (A) is unchanged and atomic number (Z) goes up by 1.

119. Positron Production Positron emission: Positrons are the anti-particle of the electron Positron emission converts a proton to a neutron

120. Other Types of Nuclear Reactions Positron ( 0 +1  ): a positive electron Electron capture: Electron capture: the capture of an electron 207

122. Nuclear Fusion Fusion small nuclei combine 2 H + 3 H 4 He + 1 n + 1 1 2 0 Occurs in the sun and other stars. Energy

123. Figure 19.6: Diagram of a nuclear power plant.

124. Fusion

125. Nagasaki was an industrialized city with a natural harbor in Western Kuushu, Japan. At 11:02 a.m., this bomb, known as the "Fat Man" bomb, exploded over the north factory district at 1,800 feet above the city to achieve maximum blast effect. Buildings collapsed. Electrical systems were shorted. A wave of secondary fires resulted, adding to their holocaust. Flash burns from primary heat waves caused most of the casualties to inhabitants. Others were burned when their homes burst into flame. Flying debris caused many injuries. A fire storm of winds followed the blast at Hiroshima as air was drawn back to the center of the burning area. Trees were uprooted. The bomb took the lives of 42,000 persons and injured 40,000 more. It destroyed 39 percent of all the buildings standing in Nagasaki. According to U.S. estimates, 40,000 people were killed or never found as a result of the second bomb. Highly penetrating radiation from the nuclear explosion had a heavy casualty effect. Energy released by the explosion of this type of atomic bomb used over Nagasaki is roughly equivalent to the power generated by exploding 20,000 tons of TNT or 40 million pounds of TNT. It would fill two good sized cargo ships. In the early stages of the explosion, temperatures of tens of millions of degrees were produced. The light emitted is roughly ten times the brightness of the sun. During the explosion, various types of radiations such as gamma rays and alpha and beta particles eminate from the explosion. These radiative particles give the atomic bomb its greatest deadliness. They may last years or even centuries in dangerous amounts. Gamma radiation and neutrons caused thousands of cases of radiation sickness in Japan. First the blood was affected, and then the blood making organs were impaired including the bone marrow, the spleen and the lymph nodes. When radiation was severe, the organs of the body became necrotic within a few days, marking the victim for certain death within a short period of time. Surveys disclosed that severe radiation injury occurred to all exposed persons within a radius of one kilometer. Serious to moderate radiation injury occurred between one and two kilometers. Persons within two to four kilometers suffered slight radiation effects. What the bomb had produced was concentrated chaos, from which no city or nation could easily or rapidly recover. No significant repair or reconstruction was accomplished until months later. On September 2, the Japanese government, which had seemed ready to fight to the death, surrendered unconditionally. Winston Churchill estimated that the lives of a million Americans and two hundred and fifty British soldiers and sailors had been saved by this sudden shortening of the war.

126. Today, there are over 130 radiocarbon dating laboratories around the world producing radiocarbon assays for the scientific community. The C14 technique has been and continues to be applied and used in many, many different fields including hydrology, atmospheric science, oceanography, geology, palaeoclimatology, archaeology and biomedicine.radiocarbon dating laboratories The 14C Method There are three principal isotopes of carbon which occur naturally - C12, C13 (both stable) and C14 (unstable or radioactive). These isotopes are present in the following amounts C12 - 98.89%, C13 - 1.11% and C14 - 0.00000000010%. Thus, one carbon 14 atom exists in nature for every 1,000,000,000,000 C12 atoms in living material. The radiocarbon method is based on the rate of decay of the radioactive or unstable carbon isotope 14 (14C), which is formed in the upper atmosphere through the effect of cosmic ray neutrons upon nitrogen 14. The reaction is: 14N + n => 14C + p (Where n is a neutron and p is a proton). The 14C formed is rapidly oxidised to 14CO2 and enters the earth's plant and animal lifeways through photosynthesis and the food chain. The rapidity of the dispersal of C14 into the atmosphere has been demonstrated by measurements of radioactive carbon produced from thermonuclear bomb testing. 14C also enters the Earth's oceans in an atmospheric exchange and as dissolved carbonate (the entire 14C inventory is termed the carbon exchange reservoir (Aitken, 1990)). Plants and animals which utilise carbon in biological foodchains take up 14C during their lifetimes. They exist in equilibrium with the C14 concentration of the atmosphere, that is, the numbers of C14 atoms and non-radioactive carbon atoms stays approximately the same over time. As soon as a plant or animal dies, they cease the metabolic function of carbon uptake; there is no replenishment of radioactive carbon, only decay. There is a useful diagrammatic representation of this process given herehere Libby, Anderson and Arnold (1949) were the first to measure the rate of this decay. They found that after 5568 years, half the C14 in the original sample will have decayed and after another 5568 years, half of that remaining material will have decayed, and so on (see figure 1 below). The half-life (t 1/2) is the name given to this value which Libby measured at 5568±30 years. This became known as the Libby half-life. After 10 half-lives, there is a very small amount of radioactive carbon present in a sample. At about 50 - 60 000 years, then, the limit of the technique is reached (beyond this time, other radiometric techniques must be used for dating). By measuring the C14 concentration or residual radioactivity of a sample whose age is not known, it is possible to obtain the countrate or number of decay events per gram of Carbon. By comparing this with modern levels of activity (1890 wood corrected for decay to 1950 AD) and using the measured half-life it becomes possible to calculate a date for the death of the sample. As 14C decays it emits a weak beta particle (b ), or electron, which possesses an average energy of 160keV. The decay can be shown: 14C => 14N + b Thus, the 14C decays back to 14N. There is a quantitative relationship between the decay of 14C and the production of a beta particle. The decay is constant but spontaneous. That is, the probability of decay for an atom of 14C in a discrete sample is constant, thereby requiring the application of statistical methods for the analysis of counting data. It follows from this that any material which is composed of carbon may be dated.Herein lies the true advantage of the radiocarbon method, it is able to be uniformly applied throughout the world. Included below is an impressive list of some of the types of carbonaceous samples that have been commonly radiocarbon dated in the years since the inception of the method:

127. Nuclear Power: Our Misunderstood Source of Electricity by Max W Carbon [Note: This article was copied from "Reactions" a publications of the American Nuclear Society, volume 14 September 1998. I thought it complimented another article I read a few years ago which stated that the amount of radiation released into the environment by fossle fuel powerplants is actually more than that released by nuclear plants. This is because of the trace amounts of natuarlly occuring radioisotopes present in all substances and the volume of gases released. When you think of shere quantity of fossle fuels burned each day, this seems to make sense.] The use of nuclear energy to generate electricity is widely misunderstood, and this presents a problem for our society. For example, that misunderstanding inhibits the growth of nuclear power, but there is little hope that the United States can meet the clean-air goals established at the recent Kyoto conference without increased reliance on it. Much of the carbon dioxide released into the atmosphere today comes from coal-burning power plants, and even a natural gas plant emits over half as much as a coal plant does; the situation will worsen as our use of electricity increases. Nuclear power, of course, emits no CO2 nor sulfur and nitrogen gases to cause acid rain. It is also important for our health as discussed below, for jobs, and for many other reasons. This lack of understanding comes in part because the public receives grossly-misleading information. For example, at the time of the Chernobyl nuclear power plant accident in Ukraine in 1986, one newspaper reported "over 20,000 dead:" although the number of known deaths had reached only 34 by 1995. An antinuclear activist has said that one pound of plutonium could kill eight billion people, although 10,000 pounds have been released into the atmosphere from weapons tests in the last 50 years enough by his estimate to kill everyone on earth several thousand times. Thus, it is important to bring facts about nuclear power to the public's attention, and this article is one effort to do so. Facts about health effects: Nuclear power results from fissioning uranium and plutonium, and radiation is released in the process. Many people believe radiations "new" and do not realize that each of us receives "background radiation" every second of our lives from the sun, the earth, inside our bodies, and elsewhere. Large quantities of radiation such as come from atomic bombs are lethal (although 80% of the deaths at Hiroshima and Nagasaki, Japan in 1945 resulted from fire and blast, not radiation). However, the levels of radiation the public receives from nuclear plants are thousands of times below those associated with bombs. During normal operation, the amount of radiation leaving a plant site is so small it is almost unmeasurable. Releases during accidents are also minimized; it is doubtful that any member of the public will die from radiation released in the Three Mile Island accident in 1979 - the only major accident in the United States in nuclear power's 37-year history. Further, there is a serious argument in scientific circles about whether low levels of radiation are even harmful; scientists on one side believe they are modestly so, while those on the other side believe that low levels are not only not harmful but actually beneficial. It is also worth noting that scientists have found no evidence of genetic effects in 30,000 children born to parents who were exposed to radiation in the atomic-bomb blasts. Incidentally, plutonium is not "the most deadly material in the world' as some times stated. In fact, it is about as dangerous as the radium formerly used on our watch dials. We have considerable knowledge about radium; between 1915 and 1925, about 4,000 women were hired in factories to paint radium solutions on dials, and they did this with tiny paintbrushes. Unfortunately, they sharpened the tips of the tips of the brushes by touching the brushes to their tongues, and relatively large quantities of radium entered their bodies. About 2% of the painters eventually died from bone cancer. After 1925, it was forbidden to touch brushes to tongues, and no further radium caused cancer deaths resulted. We have less evidence about plutonium; however, many people in laboratories and hospitals (around 50 to 75) have gotten plutonium into their bodies, and apparently no deaths have resulted from its presence there. Professor Bernard Cohen of the University of Pittsburgh has offered to eat a gram of plutonium to demonstrate that eating it is no more dangerous than eating a gram of caffeine. Facts about safety: Although not widely realized, the safety record of nuclear power has been phenomenal. There has been only one nuclear plant accident in the world in which radiation affected public health - that at Chemobyl. Here, three children had died by 1995 from thyroid cancer. (28 plant personnel died from radiation and three from explosion and burns.) However, studies by the International 'Atomic Energy Agency in 1991 and by the Organization for Economic Co-Operation and Development in 1995 concluded there had been no other health effects attributable to radiation among the public anywhere. We do not know how many more radiation induced deaths will result from the accident. There will likely be more thyroid-cancer deaths, but beyond that, there is uncertainty. The 800,000 cleanup workers received average radiation exposures of 10 Rem (a unit of exposure), but scientists have no data or experimental evidence showing any health effects of 10-Rem doses. For that and other reasons, many scientists believe the total number of deaths will not exceed a few hundred. In contrast, more-pessimistic scientists theorize that the number could be as high as several hundred per year for a few decades. These numbers should be viewed in the context of producing electricity by other methods. For example, 15,000 people died from a dam failure in India in 1979. In another example, the Natural Resources Defense Council has estimated (based on studies at the Harvard School of Public Health and at the American Cancer Society) that approximately 64,000 people die prematurely every year in 239 American metropolitan areas from tiny particulates released to the atmosphere from the burning of fossil fuels. This number extrapolates to about 100,000 deaths per year for the entire country. Coal-fired power plants are leading offenders, and one-third of these deaths (33,000 per year) are estimated to result from discharges from electricity-generating plants. For the entire world, the number would be much higher. Since nuclear plants emit no particulates, they probably save thousands of lives yearly by replacing coal plants. Incidentally, Chernobyl-type plants have not been and cannot be built in the U.S. Facts about wastes: Nuclear wastes from used (or spent) fuel are intensely radioactive and must be isolated from contact with people for a long time period. Antinuclear groups and some political leaders state repeatedly that the waste disposal problem is unsolved, and the public comes to believe this. However, most of our scientific and engineering societies believe the waste can readily be disposed of by deep underground burial - where it will be harmless. This problem should also be viewed in the context of producing electricity by other methods. The spent fuel from a nuclear plant able to supply electricity for a city of about 550,000 people will amount to about 40 tons per year of solid material with a melting point of about 5,000 degrees F. This volume is the size of a couple of automobiles and is small enough that it can readily be put back into the crust of the earth from which the uranium originally came. In contrast, a coal plant of equivalent size will generate about 7,000,000 tons of carbon dioxide, 5,000 tons of nitrogen oxides, 1,400 tons of particulates, 1,000 tons of sulfur dioxide, and up to 1,000,000 tons of ashes. These quantities are so voluminous that we have no acceptable solution for handling them. We can only discharge the gases to the atmosphere which we breathe and where they contribute to global climate change and acid rain. The particulates, too, go into the atmosphere as discussed earlier. We dispose of the ashes (sometimes containing hundreds of tons of toxic arsenic, cadmium, lead, and mercury) on the surface of the earth. Thus, a strong argument exists that electricity from nuclear plants should be preferred over that from fossil plants because of our ability to handle the wastes. In fact, it seems ironic that some states ban the building of new nuclear plants "until the waste problem is solved", whereas no such limit is placed on fossil plants where no solution to handling the CO2 is even contemplated. Facts about theft and diversion: The public wonders if nuclear fuel could be stolen by terrorist groups and used to make explosives. The practical answer is "No". Fresh fuel normally consists of uranium composed of about 96% U-238 and 4% U-235; such material cannot be made to explode. Spent fuel contains both uranium and plutonium (which is made during power plant operation from the U-238), but it would be almost impossible for a group in the U.S. to steal spent fuel and then design and construct a successful bomb. Such groups in other countries would have great difficulty, also. Of course, nations develop nuclear weapons, but no nation in the world developed its weapons from its commercial nuclear power program (except possibly India); all built weapons before they built power plants. Facts about costs: Many first-generation plants have not been economical for various reasons. However, standardized plants have been designed and are being approved by the U. S. Nuclear Regulatory Commission. They will be built at preapproved sites. These second-generation plants are expected to be competitive with coal plants and to provide electricity at no more than 10% to 15% above the cost of electricity from natural gas plants. The costs of large quantities of electricity from uranium, coal, and natural gas are well below those generated from any other source such as solar or wind energy. France exports electricity from nuclear plants for a profit. Summary: In summary, the public's perceptions about nuclear power are frequently in error. Electricity from nuclear energy offers many benefits to society and warrants serious consideration as the preferred method for generating electricity. Questions? Comments?? Patrick Gormley Patrick Gormley Revised on: 09/15/2003 at 15:44:05

128. Radiation poisoning, also called "radiation sickness" or a "creeping dose", is a form of damage to organ tissue due to excessive exposure to ionizing radiation. The term is generally used to refer to acute problems caused by a large dosage of radiation in a short period, though this also has occurred with long term exposure to low level radiation. Many of the symptoms of radiation poisoning occur as ionizing radiation interferes with cell division. This interference allows for treatment of cancer cells; such cells are among the fastest-dividing in the body, and may be destroyed by a radiation dose that adjacent normal cells are likely to survive. ionizing radiationradiationcancer The clinical name for "radiation sickness" is acute radiation syndrome as described by the CDC.[1][2][3] A chronic radiation syndrome does exist but is very uncommon; this has been observed among workers in early radium source production sites and in the early days of the Soviet nuclear program. A short exposure can result in acute radiation syndrome; chronic radiation syndrome requires a prolonged high level of exposure.acutesyndromeCDC[1][2][3]chronicradiumSoviet The use of radionuclides in science and industry is strictly regulated in most countries (in the U.S. by the Nuclear Regulatory Commission). In the event of an accidental or deliberate release of radioactive material, either evacuation or sheltering in place will be the recommended measures.radionuclidesNuclear Regulatory Commission

129. Nuclear warfare Japanese woman suffering burns from thermal radiation after a nuclear bomb explosion in 1945. Nuclear warfare is more complex because a person can be irradiated by at least three processes. The first (the major cause of burns) is not caused by ionizing radiation. Thermal burns from infrared heat radiation.infrared Beta burns from shallow ionizing radiation (this would be from fallout particles; the largest particles in local fallout would be likely to have very high activities because they would be deposited so soon after detonation and it is likely that one such particle upon the skin would be able to cause a localised burn); however, these particles are very weakly penetrating and have a short range.Betafalloutlocal fallout Gamma burns from highly penetrating radiation. This would likely cause deep gamma penetration within the body, which would result in uniform whole body irradiation rather than only a surface burn. In cases of whole body gamma irradiation (circa 10 Gy) due to accidents involving medical product irradiators, some of the human subjects have developed injuries to their skin between the time of irradiation and death.Gamma In the picture on the right, the normal clothing that the woman was wearing would have been unable to attenuate the gamma radiation and it is likely that any such effect was evenly applied to her entire body. Beta burns would be likely all over the body due to contact with fallout, but thermal burns are often on one side of the body as heat radiation does not penetrate the human body. In addition, the pattern on her clothing has been burnt into the skin. This is because white fabric reflects more infra-red light than dark fabric. As a result, the skin close to dark fabric is burned more than the skin covered by white clothing. There is also the risk of internal radiation poisoning by ingestion of fallout particles. [edit] Nuclear reactor accidentsedit Radiation poisoning was a major concern after the Chernobyl reactor accident. It is important to note that in humans the acute effects were largely confined to the accident site. Thirty-one people died as an immediate result.Chernobyl Of the 100 million curies (4 exabecquerels) of radioactive material, the short lived radioactive isotopes such as 131I Chernobyl released were initially the most dangerous. Due to their short half-lives of 5 and 8 days they have now decayed, leaving the more long-lived 137Cs (with a half-life of 30.07 years) and 90Sr (with a half-life of 28.78 years) as main dangers.curiesexabecquerels131I137Cs90Sr [edit] Other accidentsedit Improper handling of radioactive and nuclear materials lead to radiation release and radiation poisoning. The most serious of these, due to improper disposal of a medical device containing a radioactive source (teletherapy), occurred in Goiânia, Brazil in 1987. It is noteworthy that while the majority of accidents involve smaller industrial radioactive sources (typically used for radiography) a large number of the deaths which have occurred have been due to exposure to the larger sources used for medical purposes. Here is a link to the Therac-25.most seriousteletherapyGoiâniaradiographyTherac-25 [edit] Ingestion and inhalationedit When radioactive compounds enter the human body, the effects are different from those resulting from exposure to an external radiation source. Especially in the case of alpha radiation, which normally does not penetrate the skin, the exposure can be much more damaging after ingestion or inhalation. The radiation exposure is normally expressed as a committed effective dose equivalent (CEDE).committed effective dose equivalent (CEDE) [edit] [edit] Preventionedit The best prevention for radiation sickness is to minimize the dose suffered by

130. Alexander Litvinenko poisoning From Wikipedia, the free encyclopedia Ten things you may not know about Wikipedia Jump to: navigation, searchnavigationsearch Alexander Litvinenko at University College HospitalUniversity College Hospital Part of a series onToxicology and poisonToxicology (Forensic) - Toxinology History of poison (ICD-10 T36-T65, ICD-9 960-989)ConceptsPoison - Venom - Toxicant - Antidote Acceptable daily intake - Acute toxicity Bioaccumulation - Biomagnification Fixed Dose Procedure - LD50 - Lethal dose Toxic capacity - Toxicity ClassToxins and venomsNeurotoxin - Necrotoxin - Hemotoxin Mycotoxin - Aflatoxin - Phototoxin List of fictional toxinsIncidentsBradford - Minamata - Niigata Alexander Litvinenko - Bhopal 2007 pet food recalls List of poisoningsPoisoning typesElements Toxic metal (Lead - Mercury - Cadmium - Antimony - Arsenic - Beryllium - Iron - Thallium) - Fluoride - Oxygen Seafood Shellfish (Paralytic - Diarrheal - Amnesic) - Ciguatera - Scombroid Tetrodotoxin Other substances Pesticide - Organophosphate - Food Nicotine - Theobromine - Carbon monoxide - Vitamin - Medicines Living organisms Mushrooms - Plants - Related topicsHazard symbol - Carcinogen Mutagen - List of Extremely Hazardous Substances - Biological warfareToxicologyForensicToxinology History of poisonT36-T65960-989PoisonVenomToxicantAntidote Acceptable daily intakeAcute toxicity BioaccumulationBiomagnification Fixed Dose ProcedureLD50Lethal dose Toxic capacityToxicity ClassToxinsvenomsNeurotoxinNecrotoxinHemotoxin MycotoxinAflatoxinPhototoxin List of fictional toxinsBradfordMinamataNiigataBhopal 2007 pet food recalls List of poisonings Toxic metalLeadMercuryCadmiumAntimonyArsenicBerylliumIronThalliumFluorideOxygen ShellfishParalyticDiarrheal AmnesicCiguateraScombroid Tetrodotoxin PesticideOrganophosphateFood NicotineTheobromineCarbon monoxideVitaminMedicines MushroomsPlantsHazard symbolCarcinogen MutagenList of Extremely Hazardous SubstancesBiological warfare This box: view editviewedit Alexander Litvinenko was a former officer of Russian Federal Security Service, who escaped prosecution in Russia and received a political asylum in Great Britain. He authored two books, "Blowing up Russia: Terror from within" and "Lubyanka Criminal Group," where he accused Russian secret services of staging Russian apartment bombings and other terrorism acts to bring Vladimir Putin to power.Alexander LitvinenkoRussian Federal Security Servicepolitical asylumGreat BritainBlowing up Russia: Terror from withinLubyanka Criminal GroupRussian secret servicesRussian apartment bombingsother terrorism actsVladimir Putin On November 1, 2006, Litvinenko suddenly fell ill and was hospitalised. He died three weeks later, becoming the first known victim of lethal polonium-210-induced acute radiation syndrome.[1] According to doctors, "Litvinenko’s murder represents an ominous landmark: the beginning of an era of nuclear terrorism."[2][3] [4].November 12006polonium-210acute radiation syndrome[1]nuclear terrorism[2][3][4] Litvinenko's allegations about the misdeeds of the Federal Security Service of Russia (FSB) and his public deathbed accusations that the Russian government was behind his unusual malady resulted in worldwide media coverage.[5]Federal Security Service of RussiaRussian government[5] Subsequent investigations by the British government into the circumstances of Litvinenko's death led to serious diplomatic difficulties between the British and Russian governments. British authorities asserted that "we are 100 percent sure who administered the poison, where and how". However they did not disclose their evidence in the interest of a future trial. The main suspect in the case, a former officer of the Federal Protective Service of Russia Andrei Lugovoy, remains in Russia. As a member of the Duma, he now enjoys immunity from prosecution. Before he was elected, the British government tried to extradite him, but without success, as described below.Federal Protective Service of RussiaAndrei Lugovoy Contents [hide] Background Illness and poisoning – Death and last statement Death and last statement Polonium-210 Investigation – Prospects of prosecution Prospects of prosecution » Possibly related events Possibly related events Theories Suspects Other persons related to the case Chronology » Comparisons to other deaths Comparisons to other deaths References in popular culture See also References External links

131. In addition, an incident occurred in 1990 at Point Lepreau Nuclear Generating Station where several employees acquired small doses of radiation due to the contamination of water in the office watercooler with tritium contaminated heavy water [10] [11]Point Lepreau Nuclear Generating Station tritiumheavy water[10] [11]

132. Terrible effects of poison on Russian spy shown in first pictures Last updated at 09:50am on 21st November 2006 Comments (24) Comments (24) Alexander Litvinenko lies in hospital The Russian spy before the poisoning With dark, sunken eyes, prematurely bald head and a yellowing skin, this is the stark image that shows poisoned former KGB agent Alexander Litvinenko clinging to life in a British hospital. Just three weeks ago, he was a happy, healthy man with a full head of hair who regularly jogged five miles a day. Read more... Poisoned spy accused Putin of being a paedophile Commentary: Putin's agents and a licence to kill The reporter gunned down in Moscow The man who met him in the sushi barPoisoned spy accused Putin of being a paedophileCommentary: Putin's agents and a licence to killThe reporter gunned down in MoscowThe man who met him in the sushi bar Today the extraordinary bodily shutdown provoked by a tiny dose of the rat poison thallium is all too clear. Mr Litvinenko can barely lift his head, so weak are his neck muscles. He has difficulty speaking and can only talk in short, painful bursts. He now faces a bone marrow transplant because his body is producing so few white blood cells which maintain his immune system. Any infection could kill him and he has a "50-50" chance of survival. The graphic pictures of 41-year-old Mr Litvinenko were taken after he was transferred to an intensive care unit when his condition worsened. They show him lying back in his bed, propped up by a large pillow and surrounded by an array of medical apparatus, including at least two intravenous drips. Almost all his hair appears to have fallen out, while his eyebrows have thinned and are barely visible. His eyes are tired and yellowing – a clear sign of jaundice. Mr Litvinenko is being guarded by up to six police officers who were only allowing family and close friends to visit. His wife, Marina, 44, is keeping a bedside vigil while their 12-year-old son is cared for at home. Friends of the stricken former agent said yesterday that are another six Russian political dissidents living in Britain under political asylum who are fearing for their lives. The dramatic pictures emerged that Mr Litvinenko had a "cup of tea" with another former KGB agent on the day of the attack. He met Andrei Lugovoy at a central London hotel shortly before his hastily arranged sushi lunch with an Italian contact Professor Mario Scaramella. Mr Lugovoy lives in Moscow but was visiting the UK and arranged to meet Mr Litvinenko beforehand. He was being urgently sought by Scotland Yard last night but is not thought to still be in the country. The pair met when Mr Lugovoy was working as a security officer for the Russian TV station Ort which billionaire Boris Berezovsky, now exiled in Britain, once owned in Moscow. Mr Litvinenko’s friend, Alex Goldfarb, said: "Anyone who met him on that day is suspicious. The police have told that they are pursuing both the Italian and Mr Lugovoy. I would not describe Mr Lugovoy as his friend." "In the 90s they were part of the same crowd but they were not drinking buddies." Former KGB agent, Oleg Gordievsky, claimed yesterday that: "Sasha (Litvinenko) knew this man very well, he used to be part of Boris Berezovsky’s circle. Berezovsky took his best friends to England when he escaped but some remained in Russia and were put in prison." While the pictures undoubtedly illustrate the extraordinary pain Mr Litvinenko is going through, they will also be used to embarrass the Russian government. The pictures of Mr Litvinenko were released to the media yesterday by one of Britain’s leading public relations firms. Although no one was able to confirm who was footing the £10,000 a day PR bill, friends of billionaire Mr Berezovsky believe he was involved in some way. Scotland Yard now plans to reconstruct the final 24 hours before he was poisoned. Police are seizing CCTV footage from the streets, Tube trains and other public spaces to see if he was followed. They are carrying out further toxicology tests to see if any other poisons were used although thallium is thought to have been sufficient to cause such a dramatic bodily shutdown. Sources believe the plot could be far more complicated that first appears and could even be a complicated scheme to discredit Russian President Vladimir Putin. A chilling possibility remains that he was attacked in the street with a syringe or "poison pen." Experts said yesterday that a tactic was perfectly possible and could be carried in a busy street. If this was the case, it would carry echoes of the assassination in London of Bulgarian dissident Georgi Markov, who was stabbed with a poison-tipped umbrella in 1978. The extraordinary "Cold War" style saga began when Mr Litvinenko fell violently ill on November 1 after the two meetings in central London and was admitted to hospital. His wife told medical staff but he had been poisoned but it was not until November 16 that toxicology tests confirmed that thallium was in his bloodstream. The 15 man police inquiry, originally run by one of the Yard’s murder squads, is now being supervised by counterterrorist investigators, headed by Britain’s anti terror chief, Deputy Assistant Commissioner Peter Clarke. Security sources said that inquires were heavily focusing on exiled Russian tycoon Boris Berezovsky. Mr Beresovsky, who has claimed asylum in Britain, is a sworn enemy of President Vladimir Putin and has bankrolled Mr Litvinenko’s stay in Britain. He has bought his £500,000 house in North London and once co-authored a book with him which claimed to expose wrongdoing within the renamed KGB, now known as the FSB. He is now certain to be quizzed by detectives – particularly since one of the last men to see Mr Litvinenko alive, Mr Lugovoy, was once employed by him. But pro-Putin backers have claimed that the assassination attempt may even have been orchestrated by enemies of the Russian president in an attempt to blacken the president’s name. A Kremlin spokesman described the claims that the Russian security services had sponsored the "hit" as "pure nonsense" while MPs claimed that Mr Litvinenko was no longer of sufficient importance to be worth killing. A KGB source even claimed that the poisoning had been carried out by another foreign intelligence agency to embarrass the Russians. Other sources in Moscow revealed that Mr Litvinenko had once used a Chechen website to publish lurid claims about President Putin, claiming that he was a paedophile. He has also made extraordinary claims about Chelsea football club boss Roman Abramovich. He was transferred to an intensive care ward at University College Hospital in London. The toxicologist who treated him, Professor John Henry, said yesterday: "He’s yellow, jaundiced and thin and his hair has fallen out. He needs to avoid infections and a close watch must be kept on his heart. You can see some yellow in his eyes which indicates jaundice." "His head is also lolling to one side which indicates a weakness in his neck muscles." Mr Goldfarb added: "There has been a steady deterioration and he looks like a cancer patient." "This is a man who just a month ago was fit and healthy. The doctors say there is a danger of sudden heart or organ failure and moved him to intensive care as a precautionary measure." The poison and treatment Thallium is such a deadly poison that treatment has to be given within six hours to be effective. A heavy metal, it used to be commonly found in rat poisons and insecticides but has been subject to strict controls in many countries over the last 30 years because of its highly-toxic qualities. The salts of thallium are colourless, odourless, tasteless and soluble in water. Just a hefty pinch in food is enough to start a cascade of damage throughout the nervous system, lung, heart, stomach, intestines, liver and kidneys. The chemical takes the place of the essential mineral potassium, which keeps cells healthy, so it can attack several different nerve and cell systems simultaneously. Within hours it causes symptoms such as flu-like weakness, diarrhoea and vomiting, which can be confused with many viral illnesses, including food poisoning, which can delay diagnosis. Within three days of being poisoned, victims can suffer headaches, muscle problems, convulsions, coma and delerium, dementia and even psychosis. Within a few more days the victim loses all his hair – the critical clue to the nature of the poison. But it took blood tests to confirm Mr Litvinenko’s devastating diagnosis. Immediately they came back positive 15 days after the poinson was ingested doctors used a potassium antidote known as prussian blue. It is far less effective at this stage because so much damage has been done. But it will have given a small amount of help to the natural process of excretion – which can take months – because potassium binds to the same sites as thallium in the body, and can help to push it out of the body. The poison destroys white blood cells – the body’s first line of defence – which means the immune system is wiped out, leaving the patient at the mercy of infection. If he survives the acute stage of illness – and there may be a need for a bone marrow transplant – over the next couple of weeks, there is a long road to recovery. He will be left with extreme muscle weakness and need intensive physiotherapy.

133. Since 1941, when the Japanese attacked Pearl Harbor, the forces of the United States and her allies had been at war with Japan. The combined land, sea and air forces of the Allies fought back against Japan until only the Japanese homeland remained in Japanese control. On July 26, Truman issued the Potsdam Declaration, which called for Japan's unconditional surrender and listed peace terms. He had already been informed of the successful detonation of the first atomic bomb at Alamogordo, New Mexico, ten days earlier. The Japanese were warned of the consequences of continued resistance by the terms of the Potsdam Declaration, signed by President Truman and by Prime Minister Attlee of the United Kingdom and with the concurrence of Chiang Kai-Shek, President of the National Government of China. When Japan rejected the ultimatum, Truman authorized use of the bomb. Secretary of War Henry L. Stimson felt the choice of using the atomic bomb against Japan would be the "least abhorrent choice." This would be weighed against sacrificing the lives of thousands of soldiers. Military advisers had told Truman that a potential loss of about 500,000 American soldiers was at stake. It was vital to produce the greatest possible blow upon the Japanese, if the war was to be effectively shortened and the lives of the U.S. soldiers were to be saved. The atomic bomb provided such a blow. The cities of Hiroshima and Nagasaki were selected as targets after exhaustive study by military specialists. Hiroshima and Nagasaki had been virtually untouched by the U.S. and Allied bombing runs. On August 6, 1945, at 9:15 AM Tokyo time, a B-29 plane, the "Enola Gay" piloted by Paul W. Tibbets, dropped a uranium atomic bomb, code named "Little Boy" on Hiroshima, Japan's seventh largest city. In minutes, half of the city vanished. According to U.S. estimates, 60,000 to 70,000 people were killed or missing, 140,000 were injuried many more were made homeless as a result of the bomb. Deadly radiation reached over 100,000. In the blast, thousands died instantly.

134. ++In-utero Exposure (microcephaly)++ The A-bomb had serious effects on fetuses. Many were stillborn, and exposed fetuses born alive had higher infant mortality rates than other children. In-utero survivors also suffered an increased incidence of microcephaly, a syndrome characterized by an abnormally small skull, accompanied in severe cases by mental retardation. Patient with microcephaly and patient's mother (now deceased) (1986) / Courtesy of Takaharu Narita

135. Mass Defect Some of the mass can be converted into energySome of the mass can be converted into energy Shown by a very famous equation!Shown by a very famous equation! E=mc 2 EnergyMass Speed of light

136. Penetrating Ability

137. Artificial Nuclear Reactions New elements or new isotopes of known elements are produced by bombarding an atom with a subatomic particle such as a proton or neutron -- or even a much heavier particle such as 4 He and 11 B. Reactions using neutrons are called  reactions because a  ray is usually emitted. Radioisotopes used in medicine are often made by  reactions.

138. Artificial Nuclear Reactions Example of a  reaction is production of radioactive 31 P for use in studies of P uptake in the body. 31 15 P + 1 0 n ---> 32 15 P + 

139. Nuclear Fission

140. Fission is the splitting of atoms These are usually very large, so that they are not as stable Fission chain has three general steps: 1. Initiation. Reaction of a single atom starts the chain (e.g., 235 U + neutron) 2. Propagation. 236 U fission releases neutrons that initiate other fissions 3. ___________.

141. Stability of Nuclei Out of > 300 stable isotopes: Even Odd Odd Even Z N 15752 505 31 15 P 19 9 F 2 1 H, 6 3 Li, 10 5 B, 14 7 N, 180 73 Ta

142. Band of Stability and Radioactive Decay

143. Half-Life HALF-LIFE is the time that it takes for 1/2 a sample to decompose.HALF-LIFE is the time that it takes for 1/2 a sample to decompose. The rate of a nuclear transformation depends only on the “reactant” concentration.The rate of a nuclear transformation depends only on the “reactant” concentration.

144. Kinetics of Radioactive Decay For each duration (half-life), one half of the substance decomposes. For example: Ra-234 has a half-life of 3.6 days If you start with 50 grams of Ra-234 After 3.6 days > 25 grams After 7.2 days > 12.5 grams After 10.8 days > 6.25 grams

145. Types of Radioactive Decay Gamma Emission Loss of a  -ray (high-energy radiation that almost always accompanies the loss of a nuclear particle)  0000

146. The Nucleus

147. Types of Radioactive Decay Electron Capture (K-Capture) Addition of an electron to a proton in the nucleus –As a result, a proton is transformed into a neutron. p 1111 + e 0−10−1  n 1010

148. Types of Radioactive Decay Positron Emission Loss of a positron (a particle that has the same mass as but opposite charge than an electron) e 0101 C 11 6  B 11 5 + e 0101

149. Radioactive Series Large radioactive nuclei cannot stabilize by undergoing only one nuclear transformation. They undergo a series of decays until they form a stable nuclide (often a nuclide of lead).

150. Measuring Radioactivity One can use a device like this Geiger counter to measure the amount of activity present in a radioactive sample. The ionizing radiation creates ions, which conduct a current that is detected by the instrument.

151. Nuclear Fission How does one tap all that energy? Nuclear fission is the type of reaction carried out in nuclear reactors.

152. Nuclear Fission Bombardment of the radioactive nuclide with a neutron starts the process. Neutrons released in the transmutation strike other nuclei, causing their decay and the production of more neutrons. This process continues in what we call a nuclear chain reaction.

153. Nuclear Fission If there are not enough radioactive nuclides in the path of the ejected neutrons, the chain reaction will die out. Therefore, there must be a certain minimum amount of fissionable material present for the chain reaction to be sustained: Critical Mass.

155. http://www.bbc.co.uk/schools/gcsebitesize/ physics/radioactivity/backgroundradiationr ev3.shtmlhttp://www.bbc.co.uk/schools/gcsebitesize/ physics/radioactivity/backgroundradiationr ev3.shtml http://www.bbc.co.uk/schools/gcsebitesize/ physics/radioactivity/backgroundradiationr ev2.shtmlhttp://www.bbc.co.uk/schools/gcsebitesize/ physics/radioactivity/backgroundradiationr ev2.shtml

156. http://www.pbs.org/wg bh/nova/dirtybomb/so urces.htmlhttp://www.pbs.org/wg bh/nova/dirtybomb/so urces.html

157. Some Trends Nuclei with 2, 8, 20, 28, 50, or 82 protons or 2, 8, 20, 28, 50, 82, or 126 neutrons tend to be more stable than nuclides with a different number of nucleons. Nuclei with an even number of protons and neutrons tend to be more stable than nuclides that have odd numbers of these nucleons.

158. http://www.ndt- ed.org/EducationResources/HighSchool/R adiography/Graphics/Flash/transmut.swfhttp://www.ndt- ed.org/EducationResources/HighSchool/R adiography/Graphics/Flash/transmut.swf http://www.ausetute.com.au/images/nucde cay.swfhttp://www.ausetute.com.au/images/nucde cay.swf

159. http://grs.lpl.arizona.edu/curricula/animatio n/101805_Version_FINAL/gammaProject4.swfhttp://grs.lpl.arizona.edu/curricula/animatio n/101805_Version_FINAL/gammaProject4.swf Click radioactive event