RAD 202 Chapter 8 Test 4

An outer shell electron drops in to fill the hole left by the initial interaction. This is called ____________________ __________.

characteristic cascade

The incident electron interacts with the force field of the nucleus of a target atom. This is called _________ __________________.

Brems interaction

The incident electron knocks out an inner shell electron of a target atom. This is called ______________________ ____________.

characteristic interactions

____________ ___________ are represented by "straight" lines.

incident electrons

K-shell emissions form a ______________ ________ at their effective energy range of 69KeV.

characteristic peak

True or false: Characteristic photon energies are very predictable.

True

Characteristic photons will not be a part of the useful beam until the kVp is set at _____ kVp or above.

70

When mAs is changed, the result is a change in the _____________ of the emission graph.

amplitude

True or false: The energy of Brems photons is very predictable

False

Over ________ percent of the kinetic energy of the incident electrons is converted to _______.

99.8; heat

True or false: The electrons going from the cathode to the anode are traveling at 1/4 the speed of light.

False

What is the only difference between x-rays and gamma rays?

Where they originate from. X-rays are manmade and gamma rays are from the nucleus

Incident electrons are shown as __________ lines, while x-rays are shown as _______.

straight; waves

What are the 3 types of interactions that can happen from the anode?

1. Heat production

2. Brems interactions

3.Characteristic interactions

______% of incident electrons are converted from ______ energy to heat.

99.8%; kinetic

___% of incident electrons are converted from kinetic energy to x-rays.

1%

What are the 2 materials the anode can be made out of?

Tungsten and rhenium

Why is the target made out of tungsten and rhenium?

Because they have a high atomic number, therefore they can absorb a lot of heat and they have a high melting point because it gets extremely hot in the tube.

Brems interactions are called "________ rays" Why?

braking; because the incident electron slows down when it interacts with the nucleus force field and an x-ray is produce.

When an electron is slowed down it _______ energy and converts it into an _______.

loses; x-ray

An x-ray photons energy is dependent on how_________ the incident electron gets to the nucleus force field.

close

Majority of the x-ray produce in the x-ray tube are _______ interactions

Brems

What charge does the incident electron have?

negative

What charge does the force field of the nucleus have?

positive

If the incident electron is farther away in the force field of the nucleus the energy of the x-ray will be _____.

low

If the incident electron is close to the force field of the nucleus the energy of the x-ray will be _______.

high

A __________________ interaction occurs when the incident electron interact with the k-shell electrons

characteristic

True or false: The kinetic energy must overcome the binding energy. Or be greater than the binding energy for characteristic interactions

True

The technique must be _____ kVp or higher in order for a characteristic interaction to occur.

70

K-shell has the ________________ binding energy. Why?

greatest. Because of how close they are to the nucleus and because the pull the nucleus has.

In the characteristic interactions the incident electron will knock the electron out of the __-shell orbit and then one of the other orbits will rush to fill that hole.

k-shell

Higher energy ______ will be produced more from outer shell electrons because they will give off higher kinetic energy when trying to move into the k-shell orbit.

x-rays

True or false: X-rays made from the L-shell will never get out of the tube because of their low energy.

True

Under ___ kVp you will always have Brems interactions

70

True or false: The shape of the spectrum will always stay the same.

True

True or false: The height (amplitude) of the spectrum will stay the same and not change with different mAs.

False, the height changes with an increase or decrease in mAs. For instance, if you had a 400 mAs the height would be higher because it has double the amount of x-rays.

The average keV is approximately ___-___% of selected kVp

30-40%

Changes in ___ and _____ bring about changes in spectrum amplitude.

mAs; kVp

If there are different changes in kVp, then the __________ and the ____________ will change.

height; energy

High-frequency generators produce a beam with ____________ average energy.

higher

If there are changes in the generator-type (single phase, 3 phase, high efficiency) that will impact the spectrum ____________.

amplitude