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Learn about the various forms of radiation, including ionizing and electromagnetic radiation, and their interactions with matter and living organisms. Explore the basics of atomic structure, nuclear reactions, and energy production. Discover the mechanisms of radioactive decay and the characteristics of different radiation types.
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PRACTICAL RADIATION PHYSICSFOR EMERGENCY MEDICAL PERSONNEL Module III
What is radiation? Module III
Ionizing radiation Module III
Electromagnetic radiation IONIZING RADIATON VISIBLE X-RAYS COSMIC MICROVAVES INFRARED ULTRAVIOLET GAMMA TV, RADIO Decreasing wave length Increasing frequency Increasingphoton energy Module III
Forms of ionizing radiation Directly ionizing Particulate radiation • consisting of atomic or subatomic particles (electrons, protons, etc.) which carry energy in the form ofkinetic energy of mass in motion Indirectly ionizing Electromagnetic radiation • in which energy is carried by • oscillating electrical and magneticfields travelling through space atspeed of light Module III
Origin of radiation What is the relationship between atom structure and radiation production? Module III
Atom anatomy Proton Neutron Electron Nucleons Module III
Isotopes Module III
Why are some nuclides radioactive?Neutron to proton ratio Module III
Half-life Module III
Activity • The number of decaying nuclei per unit of time • The Systéme International (SI) unit of radioactivity is theBecquerel (Bq) • One Bq = 1 disintegration per second • Non-SI unit of radioactivity is theCurie (Ci) • One Ci = 3,7 x 1010 transformations per second • One milicurie (mCi) = 3,7 x 107 s-1 • One microcurie (μCi) = 3.7 x 104 s-1 • 1 Bq = 2.7 x 10-11 Ci Module III
Atomic symbols MASS NUMBER (the number of protons and neutrons) A XN SYMBOL OF ELEMENT Z The number of neutrons ATOMIC NUMBER (the number of protons) Example: 131 53I78 131I or I-131 Module III
Mass-energy relationship Measured Mass Calculated Mass E= mc2 Module III
Fission Module III
Nuclear reaction and energy production Module III
Mechanisms of radioactive decay Module III
Alpha (α++) decay AZX A-4Z-2Y + 42He e.g. 23892U 23490Th + 42He Module III
Beta (-) decay n p + e- + υ AZXAZ+1 Y +e- + e.g. 13153I13154Xe+e-+ Module III
Positron (+) decay p n + e+ + υ AZXAZ-1 Y+e++ e.g. 189F188O+e++ Module III
Electron capture p+ + e-n + AZXAZ-1 Y + 12553 I 12552 Te+ Module III
Gamma () emission Module III
Nuclear energy levels:gamma radiation SIMPLIFIED NUCLEAR MODEL Gammaray Module III
How does radiation interact with matter? Module III
Excitation Module III
Ionization Electron removal by ionization Module III
Alpha particle interaction Module III
Interaction of alpha radiation with living matter: external deposition • Alpha radiation is not external hazard. • The maximum range in tissue is <0.1 mm • All alpha radiation is absorbed in stratum corneum Module III
Interaction of alpha radiation with living matter: internal deposition Prime danger is inhalation and ingestion of alpha emitter Module III
Beta interaction with matter Module III
Interaction of beta radiation with living matter Cell nucleus Cell diameter 100 cell diameter alpha 1.7 MeV beta 0.15 MeV beta beta 5.3 MeV alpha Auger I I I I I ı 0.001 0.01 0.1 1 10 100 mm Module III
Positron interaction:annihilation reaction Module III
Neutron interaction Module III
Neutron activation Module III
Interaction of gamma radiation with matter • In terms of ionization, gamma radiation interacts with matter in three main ways 1. Photoelectric effect 2. Compton scattering 3. Pair production Module III
Gamma interaction by photoelectric effect Module III
Gamma interaction by Compton scattering Module III
Pair production Module III
Extranuclear energy release • Bremsstrahlung radiation • Characteristic X rays • Auger electrons Module III
Bremsstrahlung radiation Module III
Importance of bremsstrahlung Xrays in radiation safety practice Module III
Characteristic X rays Module III
Differencebetween X rays and gamma rays Module III
Internal conversion:Auger electrons Module III
Specific ionization andlinear energy transfer (LET) Module III
Penetrating power of radiation Module III
Review points • Characteristics of representative types of ionizing radiation • particulate, charged, and directly ionizing radiation of alpha and beta particles • particulate, uncharged, and indirectly ionizing radiation of neutrons • electromagnetic, uncharged, and indirectly ionizing radiation of gamma rays and X rays. • Radiation interacts with matter via two main processes: ionization and excitation • Energy, which comes in many forms, can be converted from one form to another • Nuclear potential energy is converted into kinetic energy through nuclear fission • Conversion of mass to energy was predicted by Albert Einstein in his mass-energy equation, E = mc2 • Penetrating power of ionizing radiation is relative to radiation type and energy Module III