Flashcards on Radiobiology: Radiation Physics and Biological Effects
Radiobiology: Radiation Physics and Biological Effects Explained
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Radiation interactions
32 cards
Card 1
Question: What is the definition of ionization in the context of radiation interactions?
Answer: Ionization is the separation of charges, specifically the ejection of one or more orbital electrons from an atom or molecule.
Card 2
Question: What is excitation in an atom or molecule due to radiation?
Answer: Excitation is the raising of an orbital electron to a higher energy level within an atom or molecule.
Card 3
Question: What energy (approx.) is dissipated per ionizing event in tissue and what wavelength does that correspond to?
Answer: About 33 eV per ionizing event, corresponding to a photon wavelength of roughly 40 nm.
Card 4
Question: Give examples of ionizing radiation types.
Answer: X-rays, γ-radiation, α- and β-radiation, protons, neutrons, and accelerated ions.
Card 5
Question: Give examples of non-ionizing radiation types.
Answer: Ultraviolet (lower energy band), visible light (including lasers), infrared, microwaves, and radiowaves.
Card 6
Question: What distinguishes ionizing from non-ionizing radiation?
Answer: Ionizing radiation has sufficient energy to cause ionization (eject electrons); non-ionizing radiation has insufficient energy for ionization and caus
Card 7
Question: Describe the photoelectric effect in photon–matter interactions.
Answer: A photon is completely absorbed by a tightly bound orbital electron, which is ejected with kinetic energy equal to the photon energy minus the electro
Card 8
Question: In the photoelectric effect, what determines the kinetic energy of the ejected electron?
Answer: Kinetic energy = incident photon energy − binding energy of the orbital electron.
Card 9
Question: How does the Compton effect (incoherent scattering) differ from the photoelectric effect?
Answer: In Compton scattering the photon interacts with a loosely bound electron, transfers part of its energy to the electron (which is ejected) and is defle
Card 10
Question: What is pair creation and what happens immediately after an electron-positron pair forms?
Answer: Pair creation is when a sufficiently energetic photon interacting near a nucleus converts into an electron-positron pair; the positron soon annihilate