Henriett Darczi Doctoral School of Environmental Sciences PhD - - PowerPoint PPT Presentation

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Henriett Darczi Doctoral School of Environmental Sciences PhD - - PowerPoint PPT Presentation

Sep 02, 2022 118 likes •702 views

Henriett Darczi Doctoral School of Environmental Sciences PhD student Northern Building 0.123A daroczi.henriett@gmail.com History 1895. Wilhelm Conrad Rntgen discovers a type of electromagnetic radiation which he calls X-rays

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Henriett Daróczi

Doctoral School of Environmental Sciences PhD student Northern Building 0.123A daroczi.henriett@gmail.com

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History

  • 1895. Wilhelm Conrad Röntgen discovers a type
  • f electromagnetic radiation which he calls X-rays
  • 1896. Henri Becquerel discovers the principle
  • f radioactive decay when he

exposes photographic plates to uranium

  • 1897. Sir Joseph John Thomson first describes his

discovery of the electron

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History

  • 1898. Marie and Pierre Curie announce

discovery of two substances they call polonium and radium.

  • 1899. Ernest Rutherford classifies two types
  • f radiation, alpha rays and beta rays.
  • Henri Becquerel discovers that radiation

from uranium consists of charged particles and can be deflected by magnetic fields.

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Marie Curie coined the term radioactivity Radiation Activity

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Marie Curie coined the term radioactivity Radiation

  • Ionizing radiation
  • Non-ionizing radiation

Activity

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Marie Curie coined the term radioactivity Radiation

  • Electromagnetic radiation
  • Particle radiation
  • Acoustic radiation
  • Gravitational radiation

Activity

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Types of decays:

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Types of decays:

  • Alpha decay
  • Beta decay
  • Gamma decay
  • Neutron emission
  • Electron capture
  • Proton emission
  • Spontaneous fission
  • Cluster decay
  • Internal conversion
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Negative Beta Decay Positive Beta Decay Electron Capture

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Negative Beta Decay Positive Beta Decay Electron Capture

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Negative Beta Decay Positive Beta Decay Electron Capture

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Negative Beta Decay

Nucleus level Nucleon level Quark level

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Negative Beta Decay

Nucleus level Nucleon level Quark level

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Negative Beta Decay Positive Beta Decay Electron Capture

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Marie Curie coined the term radioactivity Radiation Activity

  • decay/

desintergration per second

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In a simple decay, if the number of decaying nucleus is N(t)

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In a simple decay, if the number of decaying nucleus is N(t) In a general case, the activity is proportional to the number of decaying atoms

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In a simple decay, if the number of decaying nucleus is N(t) In a general case, the activity is proportional to the number of decaying atoms

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In a simple decay, if the number of decaying nucleus is N(t) In a general case, the activity is proportional to the number of decaying atoms the solution of this differential equation

Exponential Decay Law

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Exponential Decay Law Decay constant λ

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Exponential Decay Law Decay constant λ Half-life time T1/2

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Exponential Decay Law Decay constant λ Half-life time T1/2

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Exponential Decay Law Decay constant λ Half-life time T1/2

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Half-life time

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Half-life time

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Decay chain if λ1<<λ2<<λ3 … <<λi

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Decay chain if λ1<<λ2<<λ3 … <<λi

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Decay chain if λ1<<λ2<<λ3 … <<λi

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Decay chain if λ1<<λ2<<λ3 … <<λi

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Decay chain if λ1<<λ2<<λ3 … <<λi Secular equilibrium

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sheet of paper very thick layer of lead Al shielding light elements (hydrogen)

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Stochastic vs Deterministic effects Justification Limitation ALARA Time Distance Shielding

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 Stochastic vs Deterministic effects  Justification: no unnecessary use of radiation is

permitted, which means that the advantages must

  • utweigh the disadvantages

 Limitation: each individual must be protected

against risks that are too great, through the application of individual radiation dose limits

 ALARA - "As Low As Reasonably Achievable"  Time: Reducing the time of an exposure reduces

the effective dose proportionally

 Distance: Increasing distance reduces dose due

to the inverse square law

 Shielding: absorbing the energy of the radiation

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 Primordial Radionuclides  Secondary Radionuclides Cosmogenic Radionuclides Artifical Radionuclides

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 Primordial Radionuclides are produced

in stellar nucleosynthesis and supernova explosions, their half-lives are so long (>100 million years)

 Secondary Radionuclides derived from the

decay of primordial radionuclides

Cosmogenic Radionuclides are continually

being formed in the atmosphere due to cosmic rays.

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IAEA (2013)

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IAEA (2013)

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IAEA (2013)

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  • J. Porstendörfer (1994)
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Isotope sign Name First member of decay series Mother element Half-life time

222Rn

Radon

238U 226Ra

3.8 d

220Rn

Toron

232Th 224Ra

55 s

219Rn

Aktinon

235U 223Ra

4 s

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IAEA (2013)

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IAEA (2013)

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IAEA (2013)

Recoil ranges depending on media:

  • solid 20-70 nm
  • air ~60m
  • liquid100 nm
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  • J. Porstendörfer (1994)
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  • J. Porstendörfer (1994)
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 International Atomic Energy Agency (2013):

Measurement and calculation of radon releases from NORM residues. ISBN 978–92–0–142610–9

 Horváth, Á. et al. (2012): Environmental Physics Methods

Laboratory Pracitces

 Encyclopædia Britannica

https://www.britannica.com/science/neptunium-series

 J. Porstendörfer (1994): Properties and behaviour of

radon and thoron and their decay products in the air. Journal of Aerosol Science, Vol. 25, p 219-263.

 Khan et al., J Phys Chem Biophys 2017, 7:3 DOI:

10.4172/2161-0398.1000254

 nuclear-power.net  wikipedia.org