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When X-ray radiation passes through a patient, three types of interactions can occur, including coherent scattering (coherent scatter), photoelectric absorption and Compton scattering . Of these three events, the great majority of scattered X-rays in diagnostic X-ray imaging arise from Compton scattering.
In coherent scattering, the energy of the primary X-ray photon is first completely absorbed and then re-emitted by the electrons of a single atom. Because no net energy is absorbed by the atom, the re-emitted X-ray has the same energy as the original X-ray, however the direction of re-emission is totally arbitrary.
In photoelectric absorption, the energy of the X-ray photon is completely absorbed as it ejects a tightly bound electron from one of the atom's inner shells. The excess energy of the photon over that of the binding energy of the electron is carried off as kinetic energy by the ejected electron. Low energy characteristic radiation is generated as an electron from an outer shell falls into the vacated lower shell.
Finally, in Compton scattering, the interaction can be considered as a collision between a high energy X-ray photon and one of the outer shell electrons of an atom. This outer shell electron is bound with very little energy to the atom and essentially all of the energy lost by the X-ray photon in the collision is transferred as kinetic energy to the electron, and the electron is ejected from the atom. Because energy and momentum are both conserved in this collision, the energy and direction of the scattered X-ray photon depend on the energy transferred to the electron. When the initial X-ray energy is high, the relative amount of energy lost is small, and the scattering angle is small relative to the initial direction. When the initial X-ray energy is small, the scattering is more isotropic in all directions. At X-ray energies on the order of 1 MeV (the energy range used in radiation therapy), the scattering is mostly in the forward direction. At X-ray energies of 100 keV (the diagnostic imaging range), the scattering is more isotropic.
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What are the differences between the photoelectric effect and the Compton effect in terms of their interactions with matter and the behavior of photons?
The photoelectric effect involves the ejection of electrons from a material when photons of sufficient energy are absorbed, while the Compton effect involves the scattering of photons by free electrons in a material, resulting in a change in the photon's wavelength. In the photoelectric effect, photons interact with electrons in the material, leading to the ejection of electrons, while in the Compton effect, photons collide with free electrons, causing them to scatter and change direction.
How is xray radiation produced?
X-ray radiation is produced when high-energy electrons collide with a target material, which causes the electrons to release energy in the form of X-ray photons. This process, known as Bremsstrahlung radiation, occurs in X-ray machines and other devices designed to generate X-rays for medical imaging or other applications.
What are the differences between the photoelectric effect and Compton scattering in terms of their interactions with photons and electrons?
The photoelectric effect involves the ejection of electrons from a material when it absorbs photons, while Compton scattering is the process where photons collide with electrons, causing them to change direction and lose energy. The key difference is that in the photoelectric effect, electrons are ejected from the material, while in Compton scattering, electrons remain within the material but change their direction and energy.
What happens when photons collide?
when two photons collide:- 1.a new photon gets formed 2.its direction will be different from that of the two photons. 3.the energy of the photon will remain the same
Do photons conduct electricity?
No. Electricity is the movement of electrons, and photons have no electrons to move. Photons are the gauge particles for the electromagnetic force, but that's a different concept.
Are photons smaller than electrons?
Yes, photons are smaller than electrons. Photons are elementary particles that have no mass and are considered to be point-like particles, while electrons have mass and are considered to be fundamental particles with a measurable size.
Which subatomic particle of the atom in a molecule interacts with photons?
Electrons are the subatomic particles in an atom that interact with photons. When photons interact with electrons, they can be absorbed, emitted, or scattered, leading to various chemical and physical processes in a molecule.
How do electrons gain in energy in photosystem 1?
they absorb photons from sunlight
What happens when a particle and its antiparticle collide?
When a particle and its antiparticle collide, they annihilate each other and release energy in the form of photons or other particles.
What happens when two photons collide with each other?
When two photons collide with each other, they can either scatter off in different directions or combine to create new particles, such as an electron and a positron. This process is known as pair production.
Which three subatomic particles are the lightest?
The three lightest subatomic particles are electrons, neutrinos, and photons. Electrons and neutrinos have very small masses, while photons are massless.
What is produced when electrons flow through the filament if a light bulb?
When electrons flow through the filament of a light bulb, they collide with the atoms of the filament material, causing them to heat up and emit light in the form of photons. This process is known as incandescence and is what generates the light produced by the bulb.
