Target interactions- Characteristic Radiation

Two interactions that produce x-rays:

1. Bremsstrahlung

2. Characteristic

The center of the atom:

Positively charged nucleus

The charge of electrons:

Negative

The closer the electron is to the nucleus:

The stronger the binding energy (opposites attract )

Characteristic x-ray can be defined as:

Total removal of an electron

Characteristic x-ray production involves:

Incident electron and inner shell electron

What letter describes the innermost shell of an atom?

K-shell

The process of adding or removing electrons from an atom is?

Ionization

The cascade effect describes:

The movement of an electron(s) from an outer-shell into an inner-shell

The binding energy and unit of a tungsten atoms inner-shell:

69keV

The lowest kv setting possible for producing characteristic radiation:

69kVp

Which of the following statements defines electron binding energy?

a. The energy required to remove an electron from orbit

b. The energy released through the process of ionization

c. The energy of attraction between orbital electrons

d. The energy of repulsion between protons in the nucleus

a. The energy required to remove an electron from orbit

Electron binding energy is the energy required to remove an electron from orbit. This describes how tightly bound the electron is to the nucleus. Inner shell electrons have the highest binding energy because they close to the nucleus and experience the strongest attraction. Similar to the behavior of magnets, when magnets are closer together, it takes more energy to pull them apart.

How much energy is required to remove a k-shell electron from a tungsten atom?

a. 0.5 keV

b. 3 keV

c. 12 keV

d. 69.5 keV

e. 100 keV

d. 69.5 keV

The energy of characteristic photons will change when which of the following variables is modified?

a. Tube voltage

b. Tube current

c. Filtration thickness

d. Anode material

d. Anode material

Characteristic radiation is created within the x-ray tube when high-energy electrons interact with:

Inner shell electrons

The energy of a characteristic photon is dependent on which of the following variables?

1. Energy of the incident electron

2. Binding energy of orbital electrons

3. Atomic number of filtration material

1 and 2

Characteristic photon energy is equal to:

a. The kilovoltage peak (kVp) set by the technologist

b. The binding energy of outer shell electrons

c. The difference between the original and final energy of the incident electron

d. The difference between the inner-shell and outer-shell binding energy

d. The difference between the inner-shell and outer-shell binding energy

K-shell characteristic photons will NOT be produced in a Tungsten target when the incident electron energy is:

Less than 69.5 keV

What is the maximum energy of the characteristic x-rays produced if electrons incident on the tungsten target have a maximum energy of 110 keV?

Approximately 69 keV

The maximum energy of characteristic x-rays created within a tungsten target is always 69 keV, which is the difference in binding energy between the k-shell and outer shell electrons. Using an exposure technique greater than 69 keV does not increase the energy of characteristic x-rays.

he majority of x-ray photons in an x-ray beam are classified as:

a. Discrete radiation

b. Characteristic radiation

c. Bremsstrahlung radiation

d. Charged particle radiation

c. Bremsstrahlung radiation

What photon energy is produced by a tungsten anode if an L-shell electron vacancy is filled by an N-shell electron? The approximate electron binding energies for Tungsten are provided below.

K shell = 69.5 keV

L shell = 12.0 keV

M shell = 3.0 keV

N = 0.5 keV

11.5 keV

Characteristic photon energy is equal to the difference between the inner-shell and outer-shell binding energy. In this question, the L-shell binding energy (12 keV) minus the N-shell binding energy (0.5 keV) equals 11.5 keV.

What photon energy is produced by a tungsten anode if a K-shell electron vacancy is filled by an M-shell electron? The approximate electron binding energies for Tungsten are provided below.

K shell = 69.5 keV

L shell = 12.0 keV

M shell = 3.0 keV

N = 0.5 keV

66.5 keV

How does increasing kVp affect the energy of k-shell characteristic x-ray photons?

a. Increase

b. Decrease

c. No change

c. No change

Which of the following exposure settings will NOT create k-shell characteristic x-rays?

a. 10 mAs and 55 kVp

b. 2.5 mAs and 70 kVp

c. 10 mAs and 100 kVp

d. 30 mAs and 130 kVp

a. 10 mAs and 55 kVp

An exposure technique of 10 mAs and 55 kVp will not create k-shell characteristic x-rays. In fact, any technique using less than 69.5 keV will not create k-shell photons. The energy of incoming electrons must exceed the k-shell binding energy (69.5 keV) or no x-rays will be created from that shell.