X-ray production

Question 1

What are the 4 interactions

Answer 1

Excitation of target atom
Ionisation of outer shells
Ionisation of inner shells
Interaction with nucleus of target atom

Question 2

What is excitation?

Answer 2

The incident electron passes close to an outer shell electron
The electron is raised to a higher energy level and then returns to its former position
The excess energy is given out as heat

Question 3

What is outer shell ionization?

Answer 3

Incident electron removes orbiting electron by colliding with it, the electron needs more energy than the binding energy of orbiting electron to do this.
Removed electron gives out energy as heat.

Question 4

What is inner shell ionization?

Answer 4

Incident electron removes an electron from K/L shell. This leads to a “hole” in the inner shell.
An electron from a shell further out moves into the ‘hole’ and gives out energy as a photon. (the difference in binding energies of the shells)

Question 5

What is characteristic radiation caused by?

Answer 5

Inner shell ionization

As it will always have the same energy given off in the target material.

Question 6

What are the TWO interactions that can occur with each shell:- K, L

Answer 6

Kα (alpha) radiation if “hole” is filled by L shell electron

Kβ (beta) radiation if “hole” is filled by M shell electron

Lα (alpha) radiation if “hole” is filled by M shell electron

Lβ (beta) radiation if “hole” is filled by N shell electron

Question 7

What is INTERACTION WITH THE NUCLEUS?

Answer 7

The incident electron passes through the electron cloud to interact with the nucleus

The incident electron gets slowed down and changes direction and gives off loss energy as a photon.

Question 8

What is INTERACTION WITH THE NUCLEUS also known as?

Answer 8

Continuous radiation or bremsstrahlung radiation

Question 9

What are the factors involved with INTERACTION WITH THE NUCLEUS?

Answer 9

The closer the electron gets, the more braking effect meaning more energy is released

The highest energy (shortest wavelength) photon produced is when the electron comes to a stop. Known as wavelength minimum.

Question 10

State the name of the process that results in the emission of electrons from a
heated cathode.

Answer 10

Thermionic emission