Physics Hot Spots

Coherent (Thompson) scattering primarily occurs at energies below ______.

The probability of Compton scattering ________ as x-ray energy ________.

The ________ is total x-ray absorption so there cannot be more than one event per photon.

An x-ray with less than _____ (energy) cannot undergo Pair Production.

The process by which the positron unites with a free electron and the mass of both particles is converted to energy:

Cobalt 60 decays by ______ decay to an excited state of _______.

Large, unstable atoms that have a large amount of excess energy tend to undergo radioactive decay by the emission of ___________.

When a particle identical to an electron is emitted as a result of nuclear decay:

When a positron is ejected from an atomic nucleus, a nuclear proton decays into a neutron and a positron:

When an electron strays too close to the nucleus, it can be captured and combined with a proton, reversing the process for β- decay:

Both _______ and _______ result in the Z of the parent nucleus being decreased by 1 and the ^N/_Z ratio of the atom increases

This type of radiation is a result of when an electron is taken from its shell, leaving a "hole" in the shell, thus placing the atom in an unstable configuration; then an electron from a higher shell to fall/cascade to a lower shell and losing energy in the form of an x-ray to become stable

This represents a daughter product of some other kind of decay that is itself in an excited state, but instead of instantly decaying by gamma ray (γ) emission, it remains in this excited state for a given period of time & then decays.

Name the interaction in which the incident photon is absorbed but lacks sufficient energy to ionize so the atom re-emits a photon of identical energy but in a different direction:

Name the interaction in which the incident photon interacts the inner electron shells of an atom and an Auger electron is ejected:

Which interaction produces characteristic radiation:

What is the photon interaction that is most commonly witnessed in the energy ranges used in radiation therapy (1-5 MeV or 25 keV & higher)?

Which interaction is most commonly witnessed in diagnostic x-ray and CT scans:

Name the interaction in which the incident photon interacts with free (outer) electrons and ejects an electron:

Which interaction produces back-scatter?

Name the interaction in which the incident photon passes close to the nucleus, is absorbed & instantly the energy is re-emitted as an electron-positron pair (β- , β+):

What is the energy of each the electron-positron pair (the result of pair production)

Name the interaction in which the incident photon strikes the nucleus, is absorbed and then the atom emits both neutrons and gamma rays (γ rays) in an attempt to maintain stability:

Which interaction occurs mainly in high Z materials and at higher energies?

Which interaction can result in triplet production?

In which photon interaction(s) does the incident photon lose all of its energy?
(3)

Which photon interactions ionize the atom?
(2)

Which interactions do NOT ionize the atom?
(3)

What is the most important method of x-ray production in therapy machines?

The _________ effect occurs independently of atomic number.

The production of bremsstrahlung x-rays _________ with increasing atomic number.

Penumbra ________ with source size & SSD but is independent of field size.

Percentage depth dose ___________ with field size, energy & SSD but will _________ as the depth increases.

Photon energy is DIRECTLY proportional to __________.

Photon energy is _________ proportional to photon wavelength.

At a given velocity, the wavelength & __________ are inversely proportional.

The equation to find maximum number of electrons in outer shells is ______, however, the outermost shell cannot have more than ____ electrons.

The total number of protons & neutrons is known as the:

The total number of protons is known as the:

Atoms that have different numbers of protons & different numbers of neutron but the same total number of nucleons are known as:

Atoms that have the same atomic number & same atomic mass number but exist at a different energy state due to differences in nucleon arrangement are known as:

Atoms that have the same number of protons (Z) but different atomic mass number (A) are known as:

Atoms that have the same number of neutrons but different number of protons are know as:

The negative side of the x-ray tube;    Contains a filament & a focusing cup:

The positive side of the x-ray tube;  Contains the target;  Conducts electricity & radiates heat:

Due to the Heel effect, the _______ side of the x-ray tube should be positioned over the thick portion of the body.

Both photoelectric () and compton () are seen in the energy range of 50 keV - _____.