9. Interaction of Electron with Matter

Question 1

is the removal of an electron from an atom

Answer 1

Ionization

Question 2

occurs when an x-ray passes close to an orbital electron of an atom and transfers sufficient energy to the electron to remove it from the atom.

Answer 2

Ionization

Question 3

In radiologic technologies, we use the definition of the removal of an electron form an atom because once the projectile electrons hit an atom you cannot expect that the atom will gain additional electron

Answer 3

Ionization

Question 4

The orbital electron and the atom from which it was separated are called an

Answer 4

Ion pair

Question 5

The ______ is a negative ion and the remaining atom is a _____ ion

Answer 5

electron,

positive

Question 6

Outer shell electrons are simply raised to an excited, or higher, energy level then immediately drop back to their normal energy level with the emission of infrared radiation.

Answer 6

Excitation

Question 7

is the number of ion pairs produced per unit track length

Answer 7

Specific Ionization

Question 8

An exposure of 1 roentgen produces ______
ion pairs per cm^3
of air at standard temperature and pressure
(STP)

Answer 8

2.08 x 10^9

Question 9

1 cm^3 of air at STP has a mass of

Answer 9

0.001293 g

Question 10

is the amount of

exposure that will produce 2.58 x 10^-4 C (of ionization) per kg of air.

Answer 10

The official definition of the Roentgen

Question 11

is a unit of electrical charge

Answer 11

coulomb

Question 12

Since ionization produces charged particles (ions), the amount of ionization produced can be expressed in

Answer 12

coulombs

Question 13

One coulomb of charge is produced by

Answer 13

6.24 x 10^18 ionizations

Question 14

1 R = __ C/kg

Answer 14

2.58 x 10^-4 C/kg

Question 15

1 C/kg = ____ R

Answer 15

3876 R

Question 16

1 roentgen produces ______ per cm^3 of air at standard

Answer 16

2.08 x 10^9 ion pairs

Question 17

It is a measure of the rate at which energy is transferred from ionizing radiation to soft tissue.

Answer 17

Linear Energy Transfer

Question 18

It is the amount of energy released by a radioactive particle or wave over the length of its decay track.

Answer 18

Linear Energy Transfer

Question 19

Linear Energy Transfer expressed in units of _______ of track length in soft tissue

Answer 19

kiloelectron volt per micrometer (keV/μm)

Question 20

diagnostic x-rays has ___ keV/μm

Answer 20

3

Question 21

ionizes water into H and OH radicals over a very short track.

Answer 21

High LET radiation (like alpha & beta particles)

Question 22

LET

Answer 22

Linear Energy Transfer

Question 23

also ionizes water molecules, but over a much longer track

Answer 23

Low LET radiation (like X- or gamma rays)

Question 24

electrons travelling from cathode to anode

Answer 24

Projectile Electrons

Question 25

is just a measure of the total number of electrons that travel from cathode to anode

Answer 25

mAs

Question 26

mAs =

Answer 26

mC

Question 27

1 C = _____ electrons

Answer 27

6.25 x 10^18 electrons

Question 28

Unit of Energy

Answer 28

Kinetic Energy

Question 29

1 Joule = _____ eV

Answer 29

6.24 x10^18

Question 30

1 keV = ____ J

Answer 30

1.6 x10^-16

Question 31

are emitted when an outer-shell electron fills an inner-shell void

Answer 31

Characteristic x-rays

Question 32

Characteristic of the target material

Answer 32

Characteristic x-rays

Question 33

Are produced when a projectile electron is slowed by the electric field of a target atom nucleus

Answer 33

Bremsstrahlung Radiation

Question 34

“Slowed down radiation”

Answer 34

Bremsstrahlung Radiation

Question 35

Bremsstrahlung Radiation is a ____ word

Answer 35

German

Question 36

to brake

Answer 36

bremsen

Question 37

radiation

Answer 37

Strahlung

Question 38

braking radiation

Answer 38

Bremsstrahlung Radiation

Question 39

deceleration radiation

Answer 39

Bremsstrahlung Radiation

Question 40

Define as the pair of positive and negative particles produced during ionization

Answer 40

Ion pair

Question 41

In a neutral atom, the number of electrons and protons are

Answer 41

equal

Question 42

Electron binding energy decreases, as the electrons moves ______ from the nucleus

Answer 42

farther away

Question 43

During electron interaction that produces ionization there’s great chance that the _______ electrons are the one being removed (they have lesser electron binding energy)

Answer 43

outer shell

Question 44

Used in radiation therapy to burn cancer cells

Answer 44

High Linear Energy Transfer radiation

Question 45

Radiation Therapy

Answer 45

High LET radiation

Question 46

Used in general radiography (Diagnostic X-rays)

Answer 46

Low LET radiation

Question 47

produce free radicals which are elements in the body that can produce cancers (carcinogenic)

Answer 47

High LET radiation

Question 48

radiation breaks down water

Answer 48

Capable of radiolysis

Question 49

Occur in accidental leakage of power plant

Answer 49

High LET radiation

Question 50

not capable of radiolysis

Answer 50

Low LET radiation

Question 51

strike the atom in the | target and ionize to produce x-rays

Answer 51

Projectile electrons

Question 52

Velocity is speed of light, expressed in

Answer 52

m/s

Question 53

Kinetic energy is expressed in

Answer 53

Joules

Question 54

Mass is expressed in

Answer 54

Kg