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textbook:nrctextbook:chapter7 [2025-04-16 12:48]
Merja Herzig 		textbook:nrctextbook:chapter7 [2025-08-28 21:35] (current)
Merja Herzig
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   * [[textbook:nrctextbook:chapter5#excited_state|excitation]] of nuclei or atoms   * [[textbook:nrctextbook:chapter5#excited_state|excitation]] of nuclei or atoms
   * formation of electromagnetic radiation ([[textbook:nrctextbook:chapter7#bremsstrahlung|bremsstrahlung]], [[textbook:nrctextbook:chapter7#cherenkov_radiation|Cherenkov radiation]])   * formation of electromagnetic radiation ([[textbook:nrctextbook:chapter7#bremsstrahlung|bremsstrahlung]], [[textbook:nrctextbook:chapter7#cherenkov_radiation|Cherenkov radiation]])
-  * absorption into the nucleus – nuclear reaction+  * absorption into the nucleus – [[textbook:nrctextbook:chapter15|nuclear reaction]]
  
 {{anchor:ionization}} {{anchor:ionization}}
 +{{anchor:secondary_ionization}}
 +
 ### ###
-Radiation other than the neutron radiation has a much greater possibility of interacting with the [[textbook:nrctextbook:chapter2#electron|electron cloud]] than with the [[textbook:nrctextbook:chapter2#nucleus|nucleus]] due to the much larger size of the electron cloud compared to nucleus. The removal of electrons from the electron shells of the medium atoms by ionization is the central pattern by which all radiation except neutrons loses their energy when moving in the medium. While the [[textbook:nrctextbook:chapter15#cross_section|cross section]] of the ionization by [[textbook:nrctextbook:chapter2#proton|protons]] or [[textbook:nrctextbook:chapter5#alpha_particle|alpha particles]] can be several hundreds of thousands of barns (for definition, see [[textbook:nrctextbook:chapter15#cross_section|Chapter XV]]) it is only under ten for nuclear scattering and still considerably less for nuclear transformations. //Radiation, which causes ionization, is called ionizing radiation//. The primary result in ionization is the formation of ion pair, electron and positive ion. In most cases, the emitting electrons are so high in energy that they can cause further ionization, //secondary ionization//, which can be an even a larger portion of the overall ionization than the //primary ionization//. The radiation energies generated by [[textbook:nrctextbook:chapter6|radioactive decay]] are typically at least in the keV range. These are high energies compared to energies of atom ionization, which are usually less than 15 eV and those of chemical bonding, which are even lower at 1-5 eV. It is therefore understandable that electrons arising from primary ionization have such a high kinetic energy to cause secondary ionization. Similarly, it is understandable that the primary high energy of a particle or [[textbook:nrctextbook:chapter5#gamma|gamma]] ray does not lose its energy in only one collision with an electron, but several.+Radiation other than the neutron radiation has a much greater possibility of interacting with the [[textbook:nrctextbook:chapter2#electron|electron cloud]] than with the [[textbook:nrctextbook:chapter2#nucleus|nucleus]] due to the much larger size of the electron cloud compared to nucleus. The removal of electrons from the electron shells of the medium atoms by //ionization// is the central pattern by which all radiation except neutrons loses their energy when moving in the medium. While the [[textbook:nrctextbook:chapter15#cross_section|cross section]] of the ionization by [[textbook:nrctextbook:chapter2#proton|protons]] or [[textbook:nrctextbook:chapter5#alpha_particle|alpha particles]] can be several hundreds of thousands of barns (for definition, see [[textbook:nrctextbook:chapter15#cross_section|Chapter XV]]) it is only under ten for nuclear scattering and still considerably less for nuclear transformations. //Radiation, which causes ionization, is called ionizing radiation//. The primary result in ionization is the formation of ion pair, electron and positive ion. In most cases, the emitting electrons are so high in energy that they can cause further ionization, //secondary ionization//, which can be an even a larger portion of the overall ionization than the //primary ionization//. The radiation energies generated by [[textbook:nrctextbook:chapter6|radioactive decay]] are typically at least in the keV range. These are high energies compared to energies of atom ionization, which are usually less than 15 eV and those of chemical bonding, which are even lower at 1-5 eV. It is therefore understandable that electrons arising from primary ionization have such a high kinetic energy to cause secondary ionization. Similarly, it is understandable that the primary high energy of a particle or [[textbook:nrctextbook:chapter5#gamma|gamma]] ray does not lose its energy in only one collision with an electron, but several.
  
 ### ###
 {{anchor:absorption_curve}} {{anchor:absorption_curve}}
 +{{anchor:absorption_range}}
 ===== 7.1. Absorption curve and range ===== ===== 7.1. Absorption curve and range =====
  
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-{{:textbook:nrctextbook:radiation_absorption_curve_determination_system_fig_7_1.png?400|}}+{{:textbook:nrctextbook:radiation_absorption_curve_determination_system.png?400|}}
  
 Figure VII.1 Radiation absorption curve determination system (modified from  Figure VII.1 Radiation absorption curve determination system (modified from 
 https://tap.iop.org/atoms/radioactivity/511/page_47096.html). https://tap.iop.org/atoms/radioactivity/511/page_47096.html).
 {{anchor:figure_72}} {{anchor:figure_72}}
-{{:textbook:nrctextbook:adsorption_curves_of_alpha_veta_and_gamma_neutron_radiation_fig_7_2.png|}}+ 
 +{{:textbook:nrctextbook:absorption_curves_alpha_beta_gamma_l.png?400|}}
  
 Figure VII.2. Absorption curves of [[textbook:nrctextbook:chapter5#alpha|alpha]] (blue), [[textbook:nrctextbook:chapter5#beta|beta]] (grey) and [[textbook:nrctextbook:chapter5#gamma|gamma]]/neutron radiation (orange). Figure VII.2. Absorption curves of [[textbook:nrctextbook:chapter5#alpha|alpha]] (blue), [[textbook:nrctextbook:chapter5#beta|beta]] (grey) and [[textbook:nrctextbook:chapter5#gamma|gamma]]/neutron radiation (orange).
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 {{anchor:absorption_of_alpha_radiation}} {{anchor:absorption_of_alpha_radiation}}
 {{anchor:ionization_alpha_radiation}} {{anchor:ionization_alpha_radiation}}
 +{{anchor:specific_ionization}}
 ===== 7.2. Absorption of alpha radiation ===== ===== 7.2. Absorption of alpha radiation =====
  
 ### ###
 +{{anchor:cloud_chamber}}
 +{{anchor:figure_73}}{{:textbook:nrctextbook:alpha_radiation_tracks_of_226ra_source_in_a_cloud_chamber_fig_7_3.png?400 |}}
 +Figure VII.3. Alpha radiation tracks of a <sup>226</sup>Ra source imaged in a cloud chamber. (https://simple.wikipedia.org/wiki/Cloud_chamber).
 +
 In comparison to other radiation types from radioactive decay, [[textbook:nrctextbook:chapter5#alpha|alpha radiation]] is characterized by the fact that the [[textbook:nrctextbook:chapter5#alpha_particle|alpha particles]] are large and their energies are always high, usually between 4-9 MeV. Due to this, alpha particles do not readily scatter from medium atoms, rather their range is short and path is direct ([[textbook:nrctextbook:chapter7#figure_73|Figure VII.3]]). For example, the 4.8 MeV alpha particles of <sup>226</sup>Ra have a maximum range of 3.3 cm in air and only 0.0033 cm in water. Alpha radiation causes very intense ionization, for example, when traveling in air a 7.7 MeV alpha particle causes 3200 ion pairs/cm. The ion pairs generated in unit length is called specific ionization. [[textbook:nrctextbook:chapter7#figure_74|Figure VII.4]] shows specific ionization of alpha radiation (and of [[textbook:nrctextbook:chapter2#proton|protons]] and electrons) as a function of particle energy. First specific ionization somewhat increases, but at energies higher than 1 MeV specific ionization decreases systematically. The specific ionization of alpha particles is clearly higher than that of protons, let alone electrons. This is due to their larger size and higher electric charge. Most of the electrons produced in primary ionization have a high energy, on average 100 eV, but some even higher than 3 keV and thus they cause strong secondary ionization. In comparison to other radiation types from radioactive decay, [[textbook:nrctextbook:chapter5#alpha|alpha radiation]] is characterized by the fact that the [[textbook:nrctextbook:chapter5#alpha_particle|alpha particles]] are large and their energies are always high, usually between 4-9 MeV. Due to this, alpha particles do not readily scatter from medium atoms, rather their range is short and path is direct ([[textbook:nrctextbook:chapter7#figure_73|Figure VII.3]]). For example, the 4.8 MeV alpha particles of <sup>226</sup>Ra have a maximum range of 3.3 cm in air and only 0.0033 cm in water. Alpha radiation causes very intense ionization, for example, when traveling in air a 7.7 MeV alpha particle causes 3200 ion pairs/cm. The ion pairs generated in unit length is called specific ionization. [[textbook:nrctextbook:chapter7#figure_74|Figure VII.4]] shows specific ionization of alpha radiation (and of [[textbook:nrctextbook:chapter2#proton|protons]] and electrons) as a function of particle energy. First specific ionization somewhat increases, but at energies higher than 1 MeV specific ionization decreases systematically. The specific ionization of alpha particles is clearly higher than that of protons, let alone electrons. This is due to their larger size and higher electric charge. Most of the electrons produced in primary ionization have a high energy, on average 100 eV, but some even higher than 3 keV and thus they cause strong secondary ionization.
 ### ###
-{{anchor:cloud_chamber}} 
-{{anchor:figure_73}} 
  
-{{:textbook:nrctextbook:alpha_radiation_tracks_of_226ra_source_in_a_cloud_chamber_fig_7_3.png|}} 
- 
-Figure VII.3. Alpha radiation tracks of a <sup>226</sup>Ra source imaged in a cloud chamber. (https://simple.wikipedia.org/wiki/Cloud_chamber). 
 {{anchor:figure_74}} {{anchor:figure_74}}
-{{:textbook:nrctextbook:specific_ionization_of_alpha_particles_protons_and_elelctrons_fig_7_4.png|}} 
  
 +{{:textbook:nrctextbook:the_specific_ionization_of_alpha_particles_protons_electrons_l.png?400 |}}
 Figure VII.4. The specific ionization of alpha particles, protons, and electrons (ion pair/mm) in the air as a function of particle energy. Figure VII.4. The specific ionization of alpha particles, protons, and electrons (ion pair/mm) in the air as a function of particle energy.
  
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 ### ###
  
- +{{:textbook:nrctextbook:specific_ionization_of_alpha_proton_as_a_function_of_residual_range_l.png|}}
-{{:textbook:nrctextbook:specific_ionization_of_alpha_particles_and_protons_as_a_function_of_residual_range_fig_7_5.png|}} +
 Figure VII.5. Specific ionization of alpha particles and protons as a function of their residual range. Figure VII.5. Specific ionization of alpha particles and protons as a function of their residual range.
  
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 ### ###
 {{anchor:figure_76}} {{anchor:figure_76}}
-{{:textbook:nrctextbook:beta_radiation_absorption_curve_background_radiation_and_bremsstrahlung_subtraction_fig_7_6.png|}}+ 
 +{{:textbook:nrctextbook:beta_radiation_absorption_curve.png?400 |}}
 VII.6. [[textbook:nrctextbook:chapter5#beta|Beta radiation]] absorption curve, background radiation and bremsstrahlung subtraction, as well as maximum range determination. VII.6. [[textbook:nrctextbook:chapter5#beta|Beta radiation]] absorption curve, background radiation and bremsstrahlung subtraction, as well as maximum range determination.
  
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 ### ###
  
 +{{anchor:absorption_of_gamma_radiation}}
 ===== 7.4. Absorption of gamma radiation ===== ===== 7.4. Absorption of gamma radiation =====
  
textbook/nrctextbook/chapter7.1744800518.txt.gz · Last modified: 2025-04-16 12:48 by Merja Herzig

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