Chapter 7 Xray Tube Production

Almost all of the kinetic energy of the incident electron is converted to?

99% is Heat

What percentage of target interaction results in the production of xray photons?

1 percent

The types of target interaction that occur in the production of xray photons in the diagnostic range depends on?

kinetic energy of the Incident electron

Brem interactions may occur only when the incident electron interacts with?

The force field around the nucleus

Characteristic interactions may occur only when the incident electron interacts with?

An inner shell electron

During a characteristic interaction, the kinetic energy of the incident electron must be _______the electron it knocks from orbit.

Greater than that of

During a characteristic interaction, the dropping from high to lower-energy state results in the emission of?

A photon of electromagnetic energy

At the end of the characterstic cascade, the ______ shell is missing an electron.

Outermost

The K shell can hold a maximum number of ____electrons.

2

If the peak kVp is 110, the average keV energy of that beam would be?

33-44 keV (30-40%)

X rays are characterized both waves of:

Both: electromagnetic waves of short wavelength and electromagnetic waves with high frequencies

Electrons traveling from the cathode filament to the anode are called?

Primary electrons/ projectile electrons

Which have a higher energy xray emission spectra; single or three phase generators?

Three phase beams would have a higher average energy

What is the emission of infrared energy?

Kinetic energy

What is energy exerted on electrons by the nucleus of the atom?

Binding energy

What results from electrons interacting with the nuclear force field?

Brem radiation

What is energy that has ionizing potential and no mass?

Electromagnetic energy

What is the difference between xray and gamma rays?

Xray is man made, gamma is naturally occuring

At what speed do electrons strike the anode?

Half the speed of light

What are the electrons called that strike the anode?

Incident electrons

Kinetic energy of the incident photons is changed into?

Xray photons

What percent of target interactions result in the production of xray?

Less than 1 percent

99% of the incident electrons kinetic energy is converted to?

Heat

What are the two types of target interactions that occur in the diagnostic range/ tube?

Brem and characteristic

What are the determining factors of which interaction will occur?

Electron kinetic energy and binding energy

Why is tungesten used as a target material?

Atomic number, binding energies

What does brem mean in german?

Slowing or breaking

A brem interaction occurs when the incident electron interacts with the?

Force field of the nucleus

The incident electron has enough energy to pass through the?

Orbital shells

The force field of brem interactions causes the incident electron to?

Slow down and change direction

The energy lost in a brem interactions is emitted as an?

Xray photon

What is the range of energies in Brem interactions?

From peak to no energy

Characteristic xrays are emitted when ?

an outershell electron fills an inner shell void.

In a characteristic interaction, the electron from an outer shell to an inner shell causes an _____to be emitted.

Xray photon

A ________interaction is the energy difference between the binding energy of the outer and inner shell of the electrons involved.

Characteristic

Can there be only one or multiple xray photons produced in a characteristic interaction?

Many

How many electons does Tungesten have?

74

What is the binding energy of the k shell electrons?

69.5 keV

Is ionization result only from K shell interactions?

No

Which electron transfer produces a diagnostic xray?

K shell

Which interaction is the most common in the diagnostic xray range?

Brem

When is characteristic radiation kVP produced?

with kVp over 70

K shell emissions for a characteristic peak with the effecetive energy range of?

69 keV

What is the maximum possible energy of any photon?

Maximum kVp

The average photon energy is only about ______% of the kVp

30-40

When mAs is changed, what effect does it have on the emission spectrum?

Changes amplitude

When kVp is changed, what effect does it have on the emission spectrum?

Number of high energy and amplitude

When xray photons pass through a filter, what happens to the low energy xray photons?

Absorbed

What effect does the abosorbtion of xrays through a filter have on the intensity and the average photon energy?

Decreases the intensity and increases energy

What happens to the beam intensity and average photon energy when generator efficiency increases?

Increases both

What is a characteristic cascade?

The reaction of electrons dropping into the vacancy during a characteristic interaction until there is only a vancane in the outer shell

What effect does increasing mAs and kVp have on the total xray emission spectrum?

When mAs is changed, it results a change in amplitude.

When kVp is changed, it changes in the number of higher-energy photons shift right, as well as in the amplitude

What is a Brem interaction?

An incident electron interacts with the force field of a nucleus, causing the electron to slow down, thus diverting the electrons course. The electron loses energy and changes course.

What is a Characteristic interaction?

When the incident electron interacts with an inner-shell electron, knocking out the inner shell electron and continuing in a slightly different direction which creates a hole in the inner shell making the shell unstable.

3 principal parts of an xray imaging system

the operating console, high voltage generator and xray tube

true or false: stationary obj have no kinetic energy

True

kinetic energy

is the energy of motion; obj in motion have kinetic energy proportional to their mass and to the square of their velocity

true or false: Velocity is more important than mass

true; all e- have the same mass therefore electron kinetic energy is increase by raising the kVp

A low energy bremsstrahlung xray results:

when the projectile e- is barely influence by the nucleus

A maximum energy xray occurs when:

the projectile e- loses all its kinetic energy and simply drifts away from the nucleus

In diagnostic ranges most xrays are

bremsstrahlung xrays

Characteristic x-radiation is this way because?

it is characteristic of the target element.

Brem xrays are produced when

A projectile e- is slowed by the nuclear field of a target atom nucleus.

A discrete spectrum contains

only specific values

Spectrum

refers to the range of types of balls or values of any quantity such as xrays.

Characteristic xrays have precisely fixed (discrete) energies and form:

a discrete emission spectrum

Brem xrays haev a ranges of energies and form a ?

continuous emission spectrum

The max energy (in keV) of a brem xrays is:

numerically equal to the kVp of operation

Factors affecting the xray emission spectrum?

-integration:total number of xrays emitted from an xray tube ( under the curve), quantity, intensity, the larger the area under the curve the higher the intensity or quantity.

-Quality: the farther the right a spectrum is.

A change in mA or mAs results in

proportional change in amplitude of the xrays emssion spectrum at all energies

A change of KVP changes the

the amplitude and the position of the xray emission spectrum.

A change in kVp has no effect on the:

position of the discrete xay emission spectrum

Adding filtratin is sometimes called

hardening the xray beam because of he relative increase in avg energy