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TOPIC 1: HISTORY OF RADIATION (PART 2)
This document discusses different types of radiation sources. It describes natural sources like cosmic rays, terrestrial radiation from rocks and soil, and internal sources in the human body. It also covers artificial sources like medical procedures, nuclear power plants, nuclear weapons, and consumer products. The document defines ionizing radiation as high energy waves or particles that can strip electrons from atoms, and non-ionizing radiation as lower energy waves that can excite but not ionize electrons. It provides examples of different radioactive decays and how to balance nuclear equations.
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TOPIC 1: HISTORY OF RADIATION (PART 2)
- 1. TOPIC 1 :History of Radiation (PART II)
- 2. 1.0 History ofRadiation 1.1 Radiation Source 1.2 Radiation Types 1.3 Radiation Uses 1.4 Radiation Hazard
- 3. 1.1 Radiation Source 1.1.1Natural Radiation 1.1.2 Artificial Radiation
- 4. 1.1 RADIATION SOURCE Humansare exposed to radiation all the time. This radiation is called background radiation. Most of the background radiation is from natural sources (natural background radiation). A small amount of the background radiation is from artificial sources (Artificial background radiation).
- 5. 1.1 RADIATION SOURCE BACKGROUNDRADIATION Natural Background Artificial Radiation
- 6. 1.1.1 NATURAL RADIATION 1.1.1aCosmic Ray 1.1.1b Rocks and Soils 1.1.1c Human body/Food
- 7. Natural sources 1. Cosmic radiation 2.Earth's crust / Radioactive rock/ Soil (Terrestrial Radiation) 3. Human body/ Food (Internal sources) 1.1.1 Natural Background
- 8. 1.1.1a Cosmic Ray ORIGIN •Sunand outer space DOSE LEVEL •At sea level: Average cosmic radiation dose is 26 mrem /year •At higher elevations, the dose increases (amount of atmosphere shielding cosmic rays decreases)
- 9. Cosmic Ray Sun emitsradiation composed of high energy infrared radiation, visible light, and ultraviolet radiation collectively shortwave radiation (SW) Other energetic rays such as gamma rays can make it through the atmosphere to the Earth's surface. Absorbed by atmosphere but the more energetic radiations interact with the atoms in the atmosphere creating energetic neutrons and radioactive nuclides. 1.1.1a Cosmic Ray
- 10. 1.1.1a Cosmic Ray Pathof incoming solar radiation
- 11. Some other cosmogenicradionuclides are : 10Be, 26Al, 36Cl, 80Kr, 14C, 32Si, 39Ar, 22Na, 35S, 37Ar, 33P, 32P, 38Mg, 24Na,38S, 31Si, 18F, 39Cl, 38Cl , 34mCl. Cosmogenic Nuclides Nuclide Symbol Half-life Source Natural Activity Carbon 14 14C 5730 yr Cosmic-ray interactions, 14N(n,p)14C 6 pCi/g (0.22 Bq/g) in organic material Hydrogen 3 (Tritium) 3H 12.3 yr Cosmic-ray interactions with N and O, spallation from cosmic- rays, 6Li(n, alpha)3H 0.032 pCi/kg (1.2 x 10- 3 Bq/kg) Beryllium 7 7Be 53.28 days Cosmic-ray interactions with N and O 0.27 pCi/kg (0.01 Bq/kg)
- 12. 1.1.1b - Rocksand soil Rocks and soil ORIGIN Ground, rocks, building materials and drinking water supplies CONTRIBUTORS Natural radium, uranium and thorium. EXAMPLE During the radioactive decay of Uranium, Radon gas is produced which seeps through rocks underground and introduced into the atmosphere
- 13. Natural Radioactivity bythe Square Mile, 1 Foot Deep Nuclide Activity used in calculation Mass of Nuclide Activity found in the volume of soil Uranium 0.7 pCi/g (25 Bq/kg) 2,200 kg 0.8 curies (31 GBq) Thorium 1.1 pCi/g (40 Bq/kg) 12,000 kg 1.4 curies (52 GBq) Potassium 40 11 pCi/g (400 Bq/kg) 2000 kg 13 curies (500 GBq) Radium 1.3 pCi/g (48 Bq/kg) 1.7 g 1.7 curies (63 GBq) Radon 0.17 pCi/g (10 kBq/m3) soil 11 µg 0.2 curies (7.4 GBq) Total: >17 curies (>653 GBq)
- 14. Natural Radioactivity bythe Ocean Nuclide Activity used in calculation Activity in Ocean Pacific Atlantic All Oceans Uranium 0.9 pCi/L (33 mBq/L) 6 x 108 Ci (22 EBq) 3 x 108 Ci (11 EBq) 1.1 x 109 Ci (41 EBq) Potassium 40 300 pCi/L (11 Bq/L) 2 x 1011 Ci (7400 EBq) 9 x 1010 Ci (3300 EBq) 3.8 x 1011 Ci (14000 EBq) Tritium 0.016 pCi/L (0.6 mBq/L) 1 x 107 Ci (370 PBq) 5 x 106 Ci (190 PBq) 2 x 107 Ci (740 PBq) Carbon 14 0.135 pCi/L (5 mBq/L) 8 x 107 Ci (3 EBq) 4 x 107 Ci (1.5 EBq) 1.8 x 108 Ci (6.7 EBq) Rubidium 87 28 pCi/L (1.1 Bq/L) 1.9 x 1010 Ci (700 EBq) 9 x 109 Ci (330 EBq) 3.6 x 1010 Ci (1300 EBq)
- 15. 1.1.1c - HumanBody/Food HUMAN BODY/ FOOD ORIGIN Our bodies also contain natural radionuclides INTERACTION Introduced into the body when Eaten or via the food chain when meat or milk from animals grazing on the crops are consumed EXAMPLES Potassium 40, carbon-14 (Breathing), Fruits (soil and carbon- 14)
- 16. Natural Radioactivity inyour body Nuclide Total Mass of Nuclide Found in the Body Total Activity of Nuclide Found in the Body Daily Intake of Nuclides Uranium 90 µg 30 pCi (1.1 Bq) 1.9 µg Thorium 30 µg 3 pCi (0.11 Bq) 3 µg Potassium 40 17 mg 120 nCi (4.4 kBq) 0.39 mg Radium 31 pg 30 pCi (1.1 Bq) 2.3 pg Carbon 14 22 ng 0.1 µCi (3.7 kBq) 1.8 ng Tritium 0.06 pg 0.6 nCi (23 Bq) 0.003 pg Polonium 0.2 pg 1 nCi (37 Bq) ~0.6 fg
- 17. Natural Radioactivity inFood Food 40K pCi/kg 226Ra pCi/kg Banana 3,520 1 Brazil Nuts 5,600 1,000-7,000 Carrot 3,400 0.6-2 White Potatoes 3,400 1-2.5 Beer 390 --- Red Meat 3,000 0.5 Lima Bean raw 4,640 2-5 Drinking water --- 0-0.17
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- 19. 1.1.2 Artificial Source(Definition) This is background radiation resulting from human activity through the creation and use of artificial sources of radiation.
- 20. ARTIFICIAL RADIATION 1. Medical sources 2. Nuclear power stations 3.Nuclear weapons 4.Consumer products 1.1.2 Artificial Radiation
- 21. 1.1.2 Artificial Radiation Humansare exposed to radiations by medical procedures such as x-rays and radiotherapy. 1-Medical sources 2- Nuclear power stations •Major incidents from nuclear power stations have released radiations into the environment. •Nuclear waste from power station also accounts for a small proportion of artificial background radiation
- 22. 1.1.2 Artificial Radiation Nuclearweapon testing in the 1950s and 1960s resulted in an increase of radiation in the environment. •Examples: TV's, older luminous dial watches, some smoke detectors, and lantern mantles •Dose is relatively small 3- Nuclear weapon 4-Consumer products
- 24. Human Produced Nuclides NuclideSymbol Half-life Source Tritium 3H 12.3 yr Produced from weapons testing and fission reactors; reprocessing facilities, nuclear weapons manufacturing Iodine 131 131I 8.04 days Fission product produced from weapons testing and fission reactors, used in medical treatment of thyroid problems Iodine 129 129I 1.57 x 107 yr Fission product produced from weapons testing and fission reactors Cesium 137 137Cs 30.17 yr Fission product produced from weapons testing and fission reactors Strontium 90 90Sr 28.78 yr Fission product produced from weapons testing and fission reactors Technetium 99 99Tc 2.11 x 105 yr Decay product of 99Mo, used in medical diagnosis Plutonium 239 239Pu 2.41 x 104 yr Produced by neutron bombardment of 238U ( 238U + n--> 239U--> 239Np +ß--> 239Pu+ß)
- 25. SUMMARY •As a whole,these sources of natural and human-made radiation are referred to as background radiation. •The pie chart below shows the average contribution from the various sources to background radiation.
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- 29. 1.2 RADIATION TYPES 1.2.1Ionizing Radiation 1.2.2 Non-ionizing Radiation
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- 31. Ionizing radiation isproduced by unstable atoms. Unstable atoms differ from stable atoms because they have an excess of energy or mass or both. Unstable atoms are said to be radioactive. In order to reach stability, these atoms give off, or emit, the excess energy or mass. These emissions are called radiation. Radioactive decay is the spontaneous decay of atoms by emitting alpha, beta or gamma particles. New elements are always formed during alpha and beta decay Extra Notes…. Ionization & Radioactive decay
- 32. 1.2.1 Ionizing Radiation •Definition: “ It is a type of radiation that is able to disrupt atoms and molecules on which they pass through, giving rise to ions and free radicals”.
- 33. Ionizing Radiation Higher energy electromagnetic waves(x-ray, gamma) or heavy particles (beta and alpha) Enough energy to pull electron from orbit 1.2.1 Ionizing Radiation
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- 35. Photon X-rays emitted from electron orbits (KeV's) Gamma rays fromnucleus(often as part of radioactive decay) (Mev's) PHOTON 1.2.1 Ionizing Radiation
- 36. Ionizing Radiation alpha particle betaparticle Radioactive Atom X-ray gamma ray 1.2.1 Ionizing Radiation
- 37. Type of RadiationAlpha particle Beta particle Gamma ray (EM) What is it? Helium Nucleus Electron Photon Symbol Origin Nucleus Nucleus Nucleus Mass (atomic mass units) 4 1/2000 0 Charge +2 -1 0 Speed slow fast speed of light Ionizing ability high medium indirectly Penetrating power low (paper/10cm in air) medium (5mm of aluminum) high (30 cm lead) LET High (QF=20) heavy damage Low (QF=1) light damage Low (QF=1) light damage Hazard Inhaled Internal hazard, but high beta can be an external hazard to skin Internal hazard Dr. Nik Noor Ashikin Bt Nik Ab Razak
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- 39. Alpha Decay 1.2.1 IonizingRadiation
- 40. • Beta decayinvolved the ejection of a beta particle (could either be an electron or a positron) • Electrons come from a neutron and change it to a proton!! eBaCs 0 1 137 56 137 55 Beta Decay 1.2.1 Ionizing Radiation
- 41. • The “*”denotes high energy • Gamma rays are emitted when a particle has too much energy. No new elements are formed. Gamma Decay
- 42. Balancing Nuclear Equations •Both MASS and CHARGE must be conserved in any nuclear reaction • This means that the sum of masses and atomic numbers on the right and left sides of the equations must be equal! eg. The decay of Uranium-238: ThHeU 234 90 4 2 238 92 1.2.1 Ionizing Radiation
- 43. Balancing examples: HeRa4 2 226 88 eK 0 1 42 19 nHeK 1 0 4 2 241 95 2 Rn222 86 Ca42 20 Bk243 97 1.2.1 Ionizing Radiation
- 44. “ They areelectromagnetic waves incapable of producing ions while passing through matter, due to their lower energy.” 1.2.2 Non-Ionizing Radiation
- 45. Non-ionizing Radiation Lower energy electromagnetic waves Not enoughenergy to pull electron from orbit, but can excite the electron 1.2.2 Non-Ionizing Radiation
- 46. Examples on Non-ionizingRadiation Sources • Visible light • Microwaves • Radios • Video Display Terminals • Power lines • Radiofrequency Diathermy (Physical Therapy) • Lasers 1.2.2 Non-Ionizing Radiation
- 47. • Pet Scans– Uses positrons to get moving 3d image by reacting with radioactive injections • Cat Scans – 3D X-ray image • X Rays (do not include Cat Scans) • Food irradiation • Tracers, leakage, and wear in industry, density and thickness measurements • Cancer Treatment • Activation analysis, crime solving – composition determining using spectrometry • Smoke detectors • Microwave ovens • Cell/mobile phones 1.3 Radiation Uses
- 48. • Both highfrequency electromagnetic radiation and particle radiation can ionize atoms (give them a charge). • Ionized atoms can change the DNA leading to the reproduction of cancerous cells • Genetic changes 1.4 Radiation Hazard
- 49. Effects waves /cellphone Radiofrequency Ranges (10 kHz to 300 GHz) – Effects only possible at ten times the permissible exposure limit – Heating of the body (thermal effect) – Cataracts – Some studies show effects of teratoginicity and carcinogenicity. 1.4 Radiation Hazard
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