Ionizing Radiation

Question 1

Radiological physics

Answer 1

The science of ionizing radiation and its interactions with matter, with special interests in the energy absorbed by matter

Question 2

Radiation dosimetry

Answer 2

Has to do with the quantitative determination of energy

Question 3

Energy needed to cause a valence electron to escape from an atom

Answer 3

4-25 eV

Question 4

Types and sources of ionizing radiation

Answer 4

Gamma rays X Rays Fast electrons Heavy charged particles Neutrons

Question 5

Gamma ray

Answer 5

Electromagnetic radiation emitted from a nucleus or an annihilation reaction between matter and antimatter (electron and positron)

Question 6

Planks constant

Answer 6

h =6.626E-34J.s=4.136E-15keV.s

Question 7

X-ray

Answer 7

Electromagnetic radiation emitted by electrons changing atomic levels (characteristic x Ray) or slowing down in a coulomb field (bremsstrahlung)

Question 8

Energy range of x Ray

Answer 8

0.1-20 kv: low energy or soft x ray 20-120 kv: diagnostic x ray 120-300 kv: orthovoltage 200 kv - 1 Mv: intermediate 1 Mv and up: megavoltage

Question 9

Fast electors and positrons

Answer 9

Photoelectrons Compton electrons Pair production electrons Megavoltage electrons β Rays Auger electrons IC electrons δ Rays

Question 10

Photoelectrons

Answer 10

Electrons generated in a medium by photoelectric effect

Question 11

Compton electrons

Answer 11

Electrons released in a medium by Compton effect

Question 12

Pair production electrons

Answer 12

Electrons or positrons produced in a medium by pair production

Question 13

Megavoltage electrons

Answer 13

Electrons produced by linear accelerator sixth kinetic energy 4 MeV to 30 MeV

Question 14

β Rays

Answer 14

Electrons or positrons emitted from a nuclei

Question 15

Auger electrons

Answer 15

Electrons from Auger effect

Question 16

IC electrons

Answer 16

Electrons from internal conversion effect

Question 17

δ Rays

Answer 17

Electrons resulted from a charged particle collision

Question 18

Heavy charged particles

Answer 18

(Nuclei or ions) are usually obtained from acceleration by a Coulomb force field in a cyclotron or a linear accelerator

Question 19

Types of heavy charged particles

Answer 19

Proton Deuteron Triton Helium Alpha Pions Neutrons Other

Question 20

Types of ionizing radiation

Answer 20

Direct and indirect

Question 21

Directly ionizing radiation

Answer 21

Fast charged particles which deliver their energy to matter directly through Coulomb force interactions along the particles track Single stage process The absorption of energy occurs by the ionization or excitation of atoms in the medium

Question 22

Examples of directly ionizing radiation

Answer 22

Fast electrons and positrons, pions, heavy charged particles

Question 23

Indirectly ionizing radiation

Answer 23

Uncharged particles - photons or neutrons Two step process: Transfer kinetic energy to charged particles in matter Resulting charged particles transfer energy to the medium through ionization and excitation of atoms

Question 24

Examples of indirectly ionizing radiation

Answer 24

Neutrons, bremsstrahlung photons, annihilation photons, gamma ray, characteristic x ray

Question 25

Stochastic quantity

Answer 25

Values occur randomly and cannot be predicted. A particular value is determined by a probability distribution. Defined for finite domains

Question 26

Non stochastic quantity

Answer 26

Value can be predicted by calculation

Question 27

Planar fluence

Answer 27

The number of particles crossing a fixed plane in either direction per unit area of the plane (summed by scalar addition)

Question 28

Planar flux density

Answer 28

The number of particles per unit time passing through unit area of the plane on one side minus those going the other way.

Question 29

Ionizing radiation

Answer 29

Subatomic particles or electromagnetic waves that are energetic enough to detach the electrons from atoms or molecules

Question 30

Types of errors

Answer 30

Systematic Random

Question 31

Systematic Error

Answer 31

comes from the measuring instrument affect accuracy of a measurement

Question 32

Accuracy

Answer 32

Degree of closeness of a measurement of quantity to the quantities true value

Question 33

Random errors

Answer 33

Caused by unknown and unpredictable changes of the experiment associated with precision

Question 34

Precision

Answer 34

Degree to which repeated measurements under unchanged condition show the same results

Question 35

Fluence

Answer 35

Question 36

Fluence density (fluence rate)

Answer 36

Question 37

Energy Fluence

Answer 37

Question 38

Energy Fluence Density (Energy Fluence Rate)

Answer 38

Question 39

Differential fluence density

Answer 39

Question 40

Fluence Density Formula

Answer 40

Question 41

Planar Fluence below the medium planar detector

Answer 41

Question 42

Planar Fluence below the medium Sperical Detector

Answer 42

Question 43

Gamma ray equation

Answer 43

Question 44

gamma rays vs x-rays

Answer 44

gamma rays (nuclear process)

emitted from nuclear decay

annihilation of matter and antimatter

x-rays (atomic process)

when an electron transits from higher energy level to lower energy level

electron in the nuclear field loses kinetic energy

Question 45

Radiant energy (R)

Answer 45

Question 46

isotropic field planar fluence

Answer 46