radiation sources, radiation types, uses and hazard

1. TOPIC 1 : History of
Radiation (PART II)

2. 1.0 History of Radiation
1.1 Radiation Source
1.2 Radiation Types
1.3 Radiation Uses
1.4 Radiation Hazard

3. 1.1 Radiation Source
1.1.1 Natural Radiation
1.1.2 Artificial Radiation

4. 1.1 RADIATION SOURCE
Humans are exposed to radiation all the
time. This radiation is called
background radiation. Most of the
background radiation is from natural
sources (natural background
radiation). A small amount of the
background radiation is from artificial
sources (Artificial background
radiation).

5. 1.1 RADIATION SOURCE
BACKGROUND RADIATION
Natural
Background
Artificial
Radiation

6. 1.1.1 NATURAL RADIATION
1.1.1a Cosmic Ray
1.1.1b Rocks and Soils
1.1.1c Human body/Food

7. Natural sources
1. Cosmic
radiation
2. Earth's crust /
Radioactive rock/
Soil
(Terrestrial
Radiation)
3. Human body/
Food
(Internal sources)
1.1.1 Natural Background

8. 1.1.1a Cosmic Ray
ORIGIN
•Sun and outer space
DOSE LEVEL
•At sea level: Average cosmic radiation dose is 26
mrem /year
•At higher elevations, the dose increases
(amount of atmosphere shielding cosmic rays
decreases)

9. Cosmic Ray
Sun emits radiation
composed of high
energy infrared
radiation, visible light,
and ultraviolet radiation
collectively
shortwave
radiation (SW)
Other energetic
rays such as
gamma rays can
make it through
the atmosphere to
the Earth's
surface.
Absorbed by
atmosphere but
the more
energetic
radiations interact
with the atoms in
the atmosphere
creating energetic
neutrons and
radioactive
nuclides.
1.1.1a Cosmic Ray

10. 1.1.1a Cosmic Ray
Path of
incoming
solar
radiation

11. Some other cosmogenic radionuclides are :
10Be, 26Al, 36Cl, 80Kr, 14C, 32Si, 39Ar, 22Na, 35S, 37Ar, 33P, 32P, 38Mg, 24Na,38S, 31Si, 18F, 39Cl, 38Cl
, 34mCl.
Cosmogenic Nuclides
Nuclide Symbol Half-life Source
Natural
Activity
Carbon 14 14C 5730 yr
Cosmic-ray
interactions, 14N(n,p)14C
6 pCi/g (0.22
Bq/g) in organic
material
Hydrogen 3
(Tritium)
3H 12.3 yr
Cosmic-ray interactions with N
and O, spallation from cosmic-
rays, 6Li(n, alpha)3H
0.032 pCi/kg
(1.2 x 10-
3 Bq/kg)
Beryllium 7 7Be
53.28
days
Cosmic-ray interactions with N
and O
0.27 pCi/kg
(0.01 Bq/kg)

12. 1.1.1b - Rocks and soil
Rocks and soil
ORIGIN
Ground, rocks,
building materials
and drinking water
supplies
CONTRIBUTORS
Natural radium,
uranium and
thorium.
EXAMPLE
During the
radioactive decay
of Uranium, Radon
gas is produced
which seeps
through rocks
underground and
introduced into the
atmosphere

13. Natural Radioactivity by the Square Mile, 1 Foot Deep
Nuclide
Activity used
in calculation
Mass of Nuclide
Activity found in the
volume of soil
Uranium 0.7 pCi/g (25 Bq/kg) 2,200 kg 0.8 curies (31 GBq)
Thorium 1.1 pCi/g (40 Bq/kg) 12,000 kg 1.4 curies (52 GBq)
Potassium 40 11 pCi/g (400 Bq/kg) 2000 kg 13 curies (500 GBq)
Radium 1.3 pCi/g (48 Bq/kg) 1.7 g 1.7 curies (63 GBq)
Radon
0.17 pCi/g (10 kBq/m3)
soil
11 µg 0.2 curies (7.4 GBq)
Total: >17 curies (>653 GBq)

14. Natural Radioactivity by the Ocean
Nuclide
Activity used
in calculation
Activity in Ocean
Pacific Atlantic All Oceans
Uranium
0.9 pCi/L
(33 mBq/L)
6 x 108 Ci
(22 EBq)
3 x 108 Ci
(11 EBq)
1.1 x 109 Ci
(41 EBq)
Potassium 40
300 pCi/L
(11 Bq/L)
2 x 1011 Ci
(7400 EBq)
9 x 1010 Ci
(3300 EBq)
3.8 x 1011 Ci
(14000 EBq)
Tritium
0.016 pCi/L
(0.6 mBq/L)
1 x 107 Ci
(370 PBq)
5 x 106 Ci
(190 PBq)
2 x 107 Ci
(740 PBq)
Carbon 14
0.135 pCi/L
(5 mBq/L)
8 x 107 Ci
(3 EBq)
4 x 107 Ci
(1.5 EBq)
1.8 x 108 Ci
(6.7 EBq)
Rubidium 87
28 pCi/L
(1.1 Bq/L)
1.9 x 1010 Ci
(700 EBq)
9 x 109 Ci
(330 EBq)
3.6 x 1010 Ci
(1300 EBq)

15. 1.1.1c - Human Body/Food
HUMAN BODY/ FOOD
ORIGIN
Our bodies also
contain natural
radionuclides
INTERACTION
Introduced into the body
when Eaten or via the
food chain when meat
or milk from animals
grazing on the crops are
consumed
EXAMPLES
Potassium 40,
carbon-14
(Breathing), Fruits
(soil and carbon-
14)

16. Natural Radioactivity in your body
Nuclide
Total Mass of
Nuclide
Found in the Body
Total Activity of
Nuclide
Found in the Body
Daily Intake of
Nuclides
Uranium 90 µg 30 pCi (1.1 Bq) 1.9 µg
Thorium 30 µg 3 pCi (0.11 Bq) 3 µg
Potassium 40 17 mg 120 nCi (4.4 kBq) 0.39 mg
Radium 31 pg 30 pCi (1.1 Bq) 2.3 pg
Carbon 14 22 ng 0.1 µCi (3.7 kBq) 1.8 ng
Tritium 0.06 pg 0.6 nCi (23 Bq) 0.003 pg
Polonium 0.2 pg 1 nCi (37 Bq) ~0.6 fg

17. Natural Radioactivity in Food
Food
40K
pCi/kg
226Ra
pCi/kg
Banana 3,520 1
Brazil Nuts 5,600 1,000-7,000
Carrot 3,400 0.6-2
White Potatoes 3,400 1-2.5
Beer 390 ---
Red Meat 3,000 0.5
Lima Bean
raw
4,640 2-5
Drinking water --- 0-0.17

18. 1.1.2 ARTIFICIAL SOURCE

19. 1.1.2 Artificial Source (Definition)
This is background radiation
resulting from human activity
through the creation and use
of artificial sources of
radiation.

20. ARTIFICIAL
RADIATION
1. Medical
sources
2. Nuclear
power
stations
3. Nuclear
weapons
4.Consumer
products
1.1.2 Artificial Radiation

21. 1.1.2 Artificial Radiation
Humans are
exposed to
radiations by
medical procedures
such as x-rays and
radiotherapy.
1-Medical sources 2- Nuclear power stations
•Major incidents from
nuclear power stations
have released radiations
into the environment.
•Nuclear waste from
power station also
accounts for a small
proportion of artificial
background radiation

22. 1.1.2 Artificial Radiation
Nuclear weapon testing
in the 1950s and 1960s
resulted in an increase
of radiation in the
environment.
•Examples: TV's,
older luminous dial
watches, some smoke
detectors, and lantern
mantles
•Dose is relatively small
3- Nuclear
weapon
4-Consumer
products

24. Human Produced Nuclides
Nuclide Symbol Half-life Source
Tritium 3H 12.3 yr
Produced from weapons testing and fission
reactors; reprocessing facilities, nuclear weapons
manufacturing
Iodine 131 131I 8.04 days
Fission product produced from weapons testing
and fission reactors, used in medical treatment of
thyroid problems
Iodine 129 129I
1.57 x
107 yr
Fission product produced from weapons testing
and fission reactors
Cesium 137 137Cs 30.17 yr
Fission product produced from weapons testing
and fission reactors
Strontium 90 90Sr 28.78 yr
Fission product produced from weapons testing
and fission reactors
Technetium
99
99Tc
2.11 x
105 yr
Decay product of 99Mo, used in medical diagnosis
Plutonium
239
239Pu
2.41 x
104 yr
Produced by neutron bombardment of 238U
( 238U + n--> 239U--> 239Np +ß--> 239Pu+ß)

25. SUMMARY
•As a whole, these sources of natural and human-made
radiation are referred to as background radiation.
•The pie chart below shows the average contribution from
the various sources to background radiation.

26. NATURAL SOURCE

27. ARTIFICIAL SOURCE

28. VIDEO 1
VIDEO 2

29. 1.2 RADIATION TYPES
1.2.1 Ionizing Radiation
1.2.2 Non-ionizing Radiation

30. Radiation Types
Ionizing
radiation
Non-ionizing
radiation
1.2 RADIATION TYPE

31. Ionizing radiation is produced by unstable atoms.
Unstable atoms differ from stable atoms because they have
an excess of energy or mass or both.
Unstable atoms are said to be radioactive. In order to reach
stability, these atoms give off, or emit, the excess energy or
mass. These emissions are called radiation.
Radioactive decay is the spontaneous decay of atoms by
emitting alpha, beta or gamma particles.
New elements are always formed during alpha and beta
decay
Extra Notes….
Ionization & Radioactive decay

32. 1.2.1 Ionizing Radiation
• Definition:
“ It is a type of radiation that is able to disrupt
atoms and molecules on which they pass
through, giving rise to ions and free radicals”.

33. Ionizing Radiation
Higher energy
electromagnetic
waves (x-ray, gamma)
or
heavy particles (beta
and alpha)
Enough energy to pull
electron from orbit
1.2.1 Ionizing Radiation

34. 


neutron

1.2.1 Ionizing Radiation

35. Photon
X-rays
emitted from
electron orbits
(KeV's)
Gamma
rays
from nucleus(often as
part of radioactive decay)
(Mev's)
PHOTON
1.2.1 Ionizing Radiation

36. Ionizing Radiation
alpha particle
beta particle
Radioactive Atom
X-ray
gamma ray
1.2.1 Ionizing Radiation

37. Type of Radiation Alpha particle Beta particle Gamma ray (EM)
What is it? Helium Nucleus Electron Photon
Symbol
Origin Nucleus Nucleus Nucleus
Mass
(atomic mass units)
4 1/2000 0
Charge +2 -1 0
Speed slow fast speed of light
Ionizing ability high medium indirectly
Penetrating power
low
(paper/10cm in air)
medium
(5mm of aluminum)
high
(30 cm lead)
LET
High (QF=20)
heavy damage
Low (QF=1)
light damage
Low (QF=1)
light damage
Hazard Inhaled
Internal hazard, but
high beta can be
an external
hazard to skin
Internal hazard
Dr. Nik Noor Ashikin Bt Nik Ab Razak
 

38. VIDEO 3
VIDEO 4

39. Alpha Decay
1.2.1 Ionizing Radiation

40. • Beta decay involved the ejection of a beta particle (could either
be an electron or a positron)
• Electrons come from a neutron and change it to a proton!!
eBaCs 0
1
137
56
137
55 
Beta Decay
1.2.1 Ionizing Radiation

41. • The “*” denotes high energy
• Gamma rays are emitted when a particle has too much
energy. No new elements are formed.
Gamma Decay

42. Balancing Nuclear Equations
• Both MASS and CHARGE must be conserved in any
nuclear reaction
• This means that the sum of masses and atomic
numbers on the right and left sides of the equations
must be equal!
eg. The decay of Uranium-238:
ThHeU 234
90
4
2
238
92 
1.2.1 Ionizing Radiation

43. Balancing examples:
 HeRa 4
2
226
88
 eK 0
1
42
19
 nHeK 1
0
4
2
241
95 2
Rn222
86
Ca42
20
Bk243
97
1.2.1 Ionizing Radiation

44. “ They are electromagnetic waves
incapable of producing ions while
passing through matter, due to their
lower energy.”
1.2.2 Non-Ionizing Radiation

45. Non-ionizing
Radiation
Lower energy
electromagnetic
waves
Not enough energy
to pull electron from
orbit, but can excite
the electron
1.2.2 Non-Ionizing Radiation

46. Examples on Non-ionizing Radiation Sources
• Visible light
• Microwaves
• Radios
• Video Display Terminals
• Power lines
• Radiofrequency Diathermy (Physical Therapy)
• Lasers
1.2.2 Non-Ionizing Radiation

47. • Pet Scans – Uses positrons to get moving 3d image by
reacting with radioactive injections
• Cat Scans – 3D X-ray image
• X Rays (do not include Cat Scans)
• Food irradiation
• Tracers, leakage, and wear in industry, density and
thickness measurements
• Cancer Treatment
• Activation analysis, crime solving – composition
determining using spectrometry
• Smoke detectors
• Microwave ovens
• Cell/mobile phones
1.3 Radiation Uses

48. • Both high frequency electromagnetic radiation
and particle radiation can ionize atoms (give them a
charge).
• Ionized atoms can change the DNA leading to the
reproduction of cancerous cells
• Genetic changes
1.4 Radiation Hazard

49. Effects waves /cell phone
 Radiofrequency Ranges (10 kHz to 300 GHz)
– Effects only possible at ten times the permissible
exposure limit
– Heating of the body (thermal effect)
– Cataracts
– Some studies show effects of teratoginicity and
carcinogenicity.
1.4 Radiation Hazard

50. VIDEO 5