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Questions and Answers
What is the equation for the energy transferred to pair production?
What is the equation for the energy transferred to pair production?
Which interaction has a Z-dependence proportional to $Z^4$?
Which interaction has a Z-dependence proportional to $Z^4$?
What does the screening correction account for in photon interactions?
What does the screening correction account for in photon interactions?
What is the behavior of $a_{pp}$ when there is complete screening?
What is the behavior of $a_{pp}$ when there is complete screening?
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What effect does increasing photon energy have on pair production's cross-section?
What effect does increasing photon energy have on pair production's cross-section?
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Which interaction exhibits a $Z^2$ dependency alongside a logarithmic energy dependence?
Which interaction exhibits a $Z^2$ dependency alongside a logarithmic energy dependence?
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Which of the following interactions is primarily affected by photon energy, decreasing as $1/hv^3$?
Which of the following interactions is primarily affected by photon energy, decreasing as $1/hv^3$?
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What type of photon interaction is characterized by a dependence of $Z$ and the logarithm of energy?
What type of photon interaction is characterized by a dependence of $Z$ and the logarithm of energy?
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As the atomic number (Z) increases, how does the probability of the photoelectric effect (PE) change?
As the atomic number (Z) increases, how does the probability of the photoelectric effect (PE) change?
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What happens to the probability of the photoelectric effect as photon energy (E) increases?
What happens to the probability of the photoelectric effect as photon energy (E) increases?
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What is indicated by the cliffs observed on graphs of the atomic attenuation coefficient for the photoelectric effect around absorption edges?
What is indicated by the cliffs observed on graphs of the atomic attenuation coefficient for the photoelectric effect around absorption edges?
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Which statement describes how the mass attenuation coefficient behaves in relation to atomic number (Z)?
Which statement describes how the mass attenuation coefficient behaves in relation to atomic number (Z)?
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What type of electron is produced during the photoelectric effect, and how is its emission characterized?
What type of electron is produced during the photoelectric effect, and how is its emission characterized?
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What defines the three distinct regions in the atomic attenuation coefficient for the photoelectric effect?
What defines the three distinct regions in the atomic attenuation coefficient for the photoelectric effect?
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How does the photoelectric atomic cross section relate to photon energy at low energies?
How does the photoelectric atomic cross section relate to photon energy at low energies?
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What general trend is observed in the mass energy transfer coefficient during the Compton scattering process?
What general trend is observed in the mass energy transfer coefficient during the Compton scattering process?
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What is a primary charged particle used in medical physics?
What is a primary charged particle used in medical physics?
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Which of the following interactions results in the release of two 511 keV photons?
Which of the following interactions results in the release of two 511 keV photons?
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What energy level of photon is specified in the context of lead interactions for mass energy absorption coefficient calculation?
What energy level of photon is specified in the context of lead interactions for mass energy absorption coefficient calculation?
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In medical physics, which charged particle interaction is primarily responsible for ionization?
In medical physics, which charged particle interaction is primarily responsible for ionization?
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Which secondary charged particle is produced during Auger effect?
Which secondary charged particle is produced during Auger effect?
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What type of particle therapy uses heavy ions, such as Carbon-6?
What type of particle therapy uses heavy ions, such as Carbon-6?
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What happens when a positron interacts with an electron?
What happens when a positron interacts with an electron?
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Which of the following interactions is associated with the absorption of a 2 MeV photon by lead?
Which of the following interactions is associated with the absorption of a 2 MeV photon by lead?
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What is the primary result of the photoelectric effect?
What is the primary result of the photoelectric effect?
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Which photon interaction involves the production of both a photon and an electron?
Which photon interaction involves the production of both a photon and an electron?
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Which of the following correctly describes the energy dependency of the pair production interaction?
Which of the following correctly describes the energy dependency of the pair production interaction?
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During which interaction does a positron annihilate with a resting electron?
During which interaction does a positron annihilate with a resting electron?
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What happens to the kinetic energy of a Compton recoil electron for photon energies between 10 keV and 3 MeV?
What happens to the kinetic energy of a Compton recoil electron for photon energies between 10 keV and 3 MeV?
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What is the primary effect of energy transfer to the medium in Compton scattering?
What is the primary effect of energy transfer to the medium in Compton scattering?
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Which of the following interactions results in complete energy transfer from the photon to the medium?
Which of the following interactions results in complete energy transfer from the photon to the medium?
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What does the average kinetic energy of a photoelectron depend on?
What does the average kinetic energy of a photoelectron depend on?
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What effect does an incoming photon have on an electron according to Thompson scattering?
What effect does an incoming photon have on an electron according to Thompson scattering?
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In the context of the Compton effect, what happens as photon energy increases?
In the context of the Compton effect, what happens as photon energy increases?
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What is the significance of the Klein Nishina Coefficient in the Compton effect?
What is the significance of the Klein Nishina Coefficient in the Compton effect?
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What is the value of the total Compton cross-section at low energies?
What is the value of the total Compton cross-section at low energies?
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When considering the Compton scattering angles, how does side scattering compare to back and forward scattering at low energies?
When considering the Compton scattering angles, how does side scattering compare to back and forward scattering at low energies?
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What assumption is made regarding electrons in the analysis of the Compton effect?
What assumption is made regarding electrons in the analysis of the Compton effect?
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What is the primary effect of low photon energy on the electron interaction compared to higher energies?
What is the primary effect of low photon energy on the electron interaction compared to higher energies?
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Which factor does the Compton atomic cross-section depend on?
Which factor does the Compton atomic cross-section depend on?
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What is the energy dependence trend in the photoelectric effect at high photon energy (hv)?
What is the energy dependence trend in the photoelectric effect at high photon energy (hv)?
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What happens when only characteristic x-rays are emitted during the photoelectric effect?
What happens when only characteristic x-rays are emitted during the photoelectric effect?
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Which atomic number dependence trend is observed in the photoelectric effect?
Which atomic number dependence trend is observed in the photoelectric effect?
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What occurs if only Auger electrons are emitted hypothetically during the photoelectric effect?
What occurs if only Auger electrons are emitted hypothetically during the photoelectric effect?
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Which of the following represents the energy transferred to charged particles if only Auger electrons are emitted?
Which of the following represents the energy transferred to charged particles if only Auger electrons are emitted?
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How is the total energy transferred during the photoelectric effect determined?
How is the total energy transferred during the photoelectric effect determined?
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What is the outcome if no characteristic x-rays are produced during the photoelectric effect?
What is the outcome if no characteristic x-rays are produced during the photoelectric effect?
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In the photoelectric effect, what does the term 'mass attenuation coefficient' refer to?
In the photoelectric effect, what does the term 'mass attenuation coefficient' refer to?
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Study Notes
Pair Production
- The energy transferred to pair production can be calculated using the equation: E=2m0c2+KEe+KEpE = 2m_0c^2 + KE_e + KE_pE=2m0c2+KEe+KEp, where m0m_0m0 is the rest mass of an electron, ccc is the speed of light, KEeKE_eKEe is the kinetic energy of the electron, and KEpKE_pKEp is the kinetic energy of the positron.
Z-dependence
- The interaction that exhibits a Z4Z^4Z4 dependence is the photoelectric effect.
Screening Correction
- The screening correction in photon interactions accounts for the shielding of the nucleus by the surrounding electrons. This correction is especially relevant for high-energy photons.
Screening and appa_{pp}app
- When there is complete screening, the appa_{pp}app value reaches its maximum, signifying full shielding of the nucleus.
Pair Production Cross-section
- Increasing photon energy, within the range of pair production, increases the cross-section of the interaction.
Logarithmic Energy Dependence
- The interaction that exhibits a Z2Z^2Z2 dependence alongside a logarithmic energy dependence is the Compton scattering.
Photon Energy Dependence
- The interaction that is primarily affected by photon energy, decreasing as 1/hv31/hv^31/hv3 is the photoelectric effect.
Z and Logarithm of Energy
- The photon interaction that exhibits dependence on both ZZZ and the logarithm of energy is pair production.
Photoelectric Effect and Atomic Number
- As atomic number (Z) increases, the probability of the photoelectric effect (PE) also increases.
Photoelectric Effect and Photon Energy
- As photon energy (E) increases, the probability of the photoelectric effect decreases.
Atomic Attenuation Coefficient Cliffs
- The "cliffs" observed on graphs of the atomic attenuation coefficient for the photoelectric effect around absorption edges indicate the binding energy of electrons in a specific shell. When photon energy exceeds the binding energy, the photoelectric effect becomes much more probable.
Mass Attenuation Coefficient and Z
- The mass attenuation coefficient generally increases proportionally to the atomic number (Z), although the exact relationship can be more complex.
Photoelectric Effect and Electron Emission
- The electron produced during the photoelectric effect is a photoelectron, and its emission is characterized by being energetic and its ejection from the atom.
Atomic Attenuation Coefficient Regions
- The three distinct regions in the atomic attenuation coefficient for the photoelectric effect are defined by:
- Low energy region: Photoelectric effect dominates
- Intermediate energy region: Compton scattering dominates
- High energy region: Pair production dominates
Photoelectric Atomic Cross-section and Energy
- At low energies, the photoelectric atomic cross-section is inversely proportional to the fourth power of photon energy.
Compton Scattering Mass Energy Transfer Coefficient
- During the Compton scattering process, the mass energy transfer coefficient generally decreases as photon energy increases.
Primary Charged Particle
- A primary charged particle used in medical physics is an electron.
511 keV Photons
- The interaction that results in the release of two 511 keV photons is positron annihilation.
Lead Interaction Energy Level
- For calculations involving the mass energy absorption coefficient in lead, the relevant photon energy is 1 MeV.
Ionization Responsible Particle
- In medical physics, the charged particle interaction primarily responsible for ionization is the electron interaction.
Auger Effect Secondary Particle
- During the Auger effect, the secondary charged particle produced is the Auger electron.
Heavy Ion Therapy
- Particle therapy using heavy ions, such as Carbon-6, is called hadron therapy.
Positron-Electron Interaction
- When a positron interacts with an electron, annihilation occurs, resulting in the production of two 511 keV photons.
Photon Absorption by Lead
- The absorption of a 2 MeV photon by lead is primarily attributed to pair production.
Photoelectric Effect Outcome
- The primary result of the photoelectric effect is the emission of a photoelectron.
Photon-Electron Interaction
- The photon interaction involving the production of both a photon and an electron is Compton scattering.
Pair Production Energy Dependence
- The energy dependency of the pair production interaction can be described as increasing with photon energy above a threshold (1.022 MeV).
Positron Annihilation
- The interaction where a positron annihilates with a resting electron is specifically called positron annihilation.
Compton Recoil Electron Energy
- For photon energies between 10 keV and 3 MeV, kinetic energy of a Compton recoil electron increases with increasing photon energy.
Energy Transfer in Compton Scattering
- The primary effect of energy transfer to the medium in Compton scattering is the production of heat.
Complete Energy Transfer
- The interaction that results in complete energy transfer from the photon to the medium is the photoelectric effect.
Photoelectron Average Kinetic Energy
- The average kinetic energy of a photoelectron depends on the binding energy of the electron in the atomic shell, which can be influenced by the specific atom.
Photon Effect on Electron (Thompson Scattering)
- According to Thompson scattering, an incoming photon causes an electron to oscillate, which then emits radiation. The photon itself is not absorbed.
Photon Energy Increase in Compton Effect
- As photon energy increases in the Compton effect, the Compton scattering angle decreases, meaning the scattered photon is more likely to be deflected in the forward direction.
Klein-Nishina Coefficient
- The Klein-Nishina Coefficient in the Compton effect quantifies the probability of Compton scattering for a given photon energy and angle.
Compton Total Cross-section at Low Energies
- At low energies, the total Compton cross-section is proportional to the square of the electron's classical radius.
Compton Scattering Angles
- At low energies, side scattering is more prevalent compared to back and forward scattering in the Compton effect.
Compton Effect Electron Assumption
- The analysis of the Compton effect assumes that electrons are free and stationary.
Low Photon Energy Impact
- Compared to higher energies, low photon energy results in a smaller energy transfer to the electron, with a larger scattering angle.
Compton Atomic Cross-section Dependence
- The Compton atomic cross-section depends on the atomic number (Z) and the photon energy.
Photoelectric Effect Energy Dependence at High Energy
- At high photon energy (hv), the energy dependence of the photoelectric effect follows a trend of decreasing with increasing photon energy.
Characteristic X-Ray Emission
- When only characteristic x-rays are emitted during the photoelectric effect, the total energy transferred is the difference between the incident photon energy and the binding energy of the electron.
Photoelectric Atomic Number Dependence
- The photoelectric effect exhibits an atomic number (Z) dependence, characterized by an increase in probability with increasing Z.
Auger Electron Emission
- If only Auger electrons were emitted during the photoelectric effect, hypothetically, the total energy transferred would be equal to the difference between the incident photon energy and the binding energy of the electron, minus the energy associated with the Auger electron.
Energy Transferred with Auger Electrons
- The energy transferred to charged particles if only Auger electrons are emitted is equal to the energy of the Auger electron.
Total Energy Transfer in Photoelectric Effect
- The total energy transferred during the photoelectric effect is determined by adding the energy of the photoelectron and the characteristic x-rays that are emitted.
No Characteristic X-ray Emission
- If no characteristic x-rays are produced during the photoelectric effect, all the energy of the incident photon is transferred to the photoelectron.
Mass Attenuation Coefficient
- In the photoelectric effect, the term 'mass attenuation coefficient' refers to the probability per unit mass that a photon will interact via the photoelectric effect.
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Description
This lecture focuses on various interactions between photons and charged particles. It reviews key concepts such as the photoelectric effect, pair production, and attenuation coefficients, along with important equations and diagrams. Students will deepen their understanding of photon behavior and related phenomena in physics.
