Toàn tập -NUCLEAR PHYSICS

INTERACTIONS OF IONIZING RADIATION WITH MATTERS
DR. CHAU VAN TAO
DEPARTMENT OF NUCLEAR PHYSICS
NATURALSCIENCES UNIVERSITY
Questions
What is radiation?
What is ‘ionizing’ radiation?
How do we measure radiation?
Where does radiation come from?
What are the effects of radiation?
Is radiation good for anything?
nucleus
proton
neutron
electron
Atomic Structure and Radioactive Decay
Atomic Structure
Röntgen
1895
Discovery of X-ray
Pierre & Marie Curie
1898

Discovery of Ra, Po
Becquerel
1896
Spontaneous radioactivity
　Hahn
1938

Discovery of fission
Discovery of Radiation
Discovery of Radiation
Ernest Rutherford(1871-1935) Albert Einstein(1879- 1955)

Types of Radiation and Nuclear Energy
Atomic Structure and Radioactive Decay
Atoms and Isotopes
XN
A
Z
X: Chemical Symbol
A: Atomic mass number
Z: Atomic number
N: Neutron number
or
X-A
He
4
2
He-4
A=Z+N
4 2 2
electron
Atomic Structure and Radioactive Decay
Co-60
Proton : 27
Neutron: 33
Ni-60*
Proton : 28
Neutron: 32
b
b-decay and g-ray emission
Ni-60
Proton : 28
Neutron: 32
g
electromagnetic
radiation
More Radioactivity
60Co
Beta ray
(electron)
226Ra
Alpha ray
(helium nucleus)
7Be
Gamma ray
7Be  7Li + 
11C  11B + +
60Co  60Ni + –
226Ra  222Rn + 
11C
Positron
Antoine Henri Becquerel
(1852—1908)
Discovered radioactivity of uranium
proton
neutron
Atomic Structure and Radioactive Decay
a-decay
U-238
Proton : 92
Neutron: 146
Th-234
Proton : 90
Neutron: 144
a
nucleus
a, b, g-ray
Lead block
Radioactive substance
b-ray
g-ray
a-ray
(+)
(-)
Electrically charged plates
Photographic plate
Types of Radiation
Types of Radiation
Types of Radiation
Types of Radiation
Half-life Time of Radionuclide
Characteristics of Radiation
A = A0e-lt
l: Probability of disintegration per unit time
Half Life,Ｔ1/2 = log2 / l
Half-life Time of Radionuclide
Characteristics of Radiation
Characteristics of Radiation
Penetrating Distances
a
b
g and X
neutron
Paper Plastic Lead Concrete
Skin Aluminum Iron Water
Electromagnetic Radiation
f = c/
‘Ionizing’ Radiation
-
-
Radiation that is energetic enough to remove a tightly bound electron from a neutral atom
Radiation
Electron
Ion
‘Ionizing’ Radiation
Different kinds of radiation produce different patterns of ionization
Electromagnetic Spectrum
Ionizing
Non ionizing
Measuring Radiation (Ion Chamber)
Measuring Radiation (Geiger Counter)
Geiger–Müller Tube
Measuring Radiation (Scintillator)
1024…
4096…
410
= 1,048,576
Scintillator
Light guide
Photomultiplier tube
Dynodes
Electrical pulse
Photocathode
The Gamma Spectrometer
Lesson 1 - Inverse Square Law of Gamma Radiation
I0
x1
I1
I0
x2
I1
I2
I0
mm
mm
logk-2logx
Io
Lesson 2 –The Decrease Of Gamma Intensity
Interaction of Radiation with Matter
Interaction of Electromagnetic Radiation
with Matter
Photoelectric Effect
photoelectron
g-ray
e-
E:  energy of the incident photon
Es:  energy of the scattered photon
q :  the scattering angle
m:  electron mass
Interaction of Radiation with Matter
Interaction of Electromagnetic Radiation
with Matter
Compton Scattering
g-ray
g1’-ray
electron
e-
Pair Production
Interaction of Radiation with Matter
E  =  2mc2 + E+ + E-
m:  electron rest mass
c:  the speed of light
E+:  kinetic energies of the positron
E-:  kinetic energy of the electron
Interaction of Electromagnetic Radiation
with Matter
positron
electron
g-ray
e-
e+
Interaction of Radiation with Matter
Photoelectric Effect
Pair Production
Compton Scattering
µ
mm
mm
-x
electron
Co-60
Proton : 27
Neutron: 33
Ni-60*
Proton : 28
Neutron: 32
b

Lesson 3 - The Gamma Spectrum

Ni-60
Proton : 28
Neutron: 32
g
electromagnetic
radiation

Lesson 3 - The Gamma Spectrum


Cobalt Spectrum

THANK YOU FOR ATTENTION