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Flashcards in Interaction With matter Deck (39):
1

Interaction of radiation with matter

Particle interaction
Photons and gamma ray interaction

2

Charged particle lose energy by interacting with orbital electrons

Excitation and ionization

3

Transfer of energy to electrons

Excitation

4

Also known as de- excitation process

Auger effect

5

The electron makes a transition to vacancy

Auger electron

6

Ejection of an electronresulting to ion pair

Ionization

7

Electrons posses sufficient energy to produce further ionizations

Secondary ionization / delta rays

8

_____ of energy deposits on soft tissue in soft tissue occurs via ionization

70%

9

As electron energy ______ , the energy loss via excitation ______

Decreases
Increases

10

Average number of primary and secondary ion pairs

Specific ionization

11

Specific ionization is expressed in

Ion pairs per millimeter (IP /mm)

12

Spcific ionization increases with

Square of the electrical charge ( Q) of the particle

13

As coulombic field ______ , the incident particle velocity _____

Increases
Decreases

14

Kinetic energy of alpha particles by natural occuring radionuclides extend from

4.05 MeV /in 2.49 air ( Th -232) - 10.53 MeV/ 11.6 cm ( Po -212)

15

Specific ionization on air

7000 lp/mm

16

Specific ionization on soft tissue

10 million lp/mm

17

Alpha particle slows down , specific ionization increases to the maximum

Maximum alpha ray

Bragg peak

18

Paths of heavy charged particles in matter

Charged particle tracks

19

Distance travelled by a particle

Path length

20

Depth of penetration of the particle in matter

Range

21

Electrons follow a _________ as a result in multiple scattering caused by coulmbic deflection

Tortuous path

22

Coulombic deflection

Repulsion/ attraction

23

Heavy charged particle results in dense and

Linear ionization track

24

Measure of the average amount of energy deposited locally

Linear Energy Transfer

25

LET is often expreesed in units

keV /mm
eV /mm

26

LET of a charged particle is proportional to

Square of the charge

27

LET of a charged particle is inversely proportional to

Particle's kinetic energy

28

Produces shorter range and more damaging to the cells

High LET radiation

29

Higsr range in matter and less damaging

Low LET radiation

30

Interaction that deflects a particle or photon from its trajectory

Scattering

31

Total kinetic energy of the colliding particle is unchanged

Elastic scattering

32

Occurs wit a loss of kinetic energy or change in energy

Inelastic

33

Electrons undergoing inelastic interaction emits electromagnetic radiation

Radiative interaction

34

RadiTion emission accompanying electron deceleration

Bremsstrahlung radiation

35

Bresstrahlung is a german word meaning

Breaking radiation

36

When a positron reaches the end of its range

Positron annihilation

37

Positron annihilation forms 2 opposite directed _______ photons

0.511 MeV

38

It cannot cause excitation or ionization but interacts with the nuclei

Neutron Interaction

39

Neutron interaction is like ________ producing recoil niclei that lose energy

"Billiard ball scatter