Introduction to
Nuclear Technology
复旦大学核科学与技术系
沈皓 haoshen@fudan.edu.cn
What
Chapter 1. Introduction and Basic concepts
Chapter 2. Radiation
Chapter 3. Basic Instrumentation for Nuclear Technology
Chapter 4. Power From Fission
Chapter 5. Thermonuclear Fusion
Chapter 6. Nuclear Weapons
Chapter 7. Nuclear Waste
Chapter 8. Radioactive isotopes and Their Applications
Chapter 9. Nuclear Analysis Methods
Chapter 10. Nuclear Technology in Industry and
Agriculture
Chapter 11. Medical Applications of Nuclear Technology
Chapter 12. Impact, Issues and Future of Nuclear
Technology
References
1) Fundamentals of Nuclear Science and Engineering,
J.Kenneth Shultis and Richard E.Faw (Marcel Dekker)
2) Nuclear Physics - Principles and Applications, J.S.Lilley,
(John Wiley & Sons, Ltd )
3) Nuclear Technology, Joseph A. Angelo,Jr (Greenwood
Press)
4) Nuclear Energy – Principles, Practices, and Prospects,
David Bodansky (Springer)
5) Introduction to Nuclear Technology, Lecture notes by
Chung Chieh
The Assessment
• Class discussion and home work 40%
• Midterm report 10%
• Final Exam 50%
one’s work is performed honestly !
Chapter 1. Introduction and Basic concepts
1.The Significance of Nuclear Technology
2.Early Discoveries
3.Basic Facts and Definitions
4.Units
SI system, Physical constants, natural unit
5.Nuclear Reactions
Discovery of nuclear reactions (n.r.).
Energy in n.r.
Neutron induced nuclear reactions
Simple theories or concepts related to n.r.
Types of n.r.
Applications of n.r.
1.1 The Significance of Nuclear Technology
1)Widely applied
Nature’s Hierarchy – a biological view
???
Sub-Atomic Particles
Atom
Molecule
Organelle
Cell
Tissue
Organ
Organ System
Multicellular Organism
Population
Community
Ecosystem
Biosphere
6
1)Widely applied
• medicine, basic research, agriculture, industry,
archaeology, geology, environmental science, and space
exploration
• nuclear technology has played a dominant role in
national security and geopolitics
• GDP 4.7% (USA)
Extensively Collaboration
1.1 The Significance of Nuclear Technology
2) Alter the course of Human civilization
Enrico Fermi nuclear reactor
1942
Started a new technical era
human beings might wisely harvest
the energy within the atomic nucleus
in a controlled manner
Prometheus stole fire from Mount Olympus
control of fire ultimately enabled the human
race to evolve into the technically complex
global civilization
05:29:45，J uly16，1945
Atomic Bomb - the age of nuclear
weaponry.
Human beings were capable of
unleashing wholesale
destruction on planet Earth
Pandora Box deliver misfortune
into the house of man
1.1 The Significance of Nuclear Technology
3) Skill and Wisdom
how the technology works
INNOVATION
to make a unanimous decision to promote and
harvest only the beneficial aspects of nuclear
technology
CAREFULNESS
Instead of becoming the destroyer of worlds,
nuclear technology should represent a powerful
technology that serves as the saver of worlds
and the protector of Earth
CONSCIENCE
1.2 Early Discoveries
Leucippus and Democritus (c. 460–c. 370 B.C.)
The theory of atomism--The Four Elements
Earth
Air
Fire
Water
Democritus，atomos (ατομος), “not divisible.”
• 1803, J.Dalton， suggested that each chemical
element was composed of a particular type of atom.
• 1811, A.Avogadro, Avogadro’s Law.
• 1869, Mendeleev，
the molecule as the
smallest particle of
any substance
molecules,
consisted of
collections of atoms
？
Is an atom divisible
Dalton’s Atomic Theory
Dalton (1766-1844 ): all substances are made of small, indivisible, and
fundamental natural units called atoms.
The law of partial
pressure of gases:
Various symbols like these had
been used to represent atoms of
different elements by Dalton
the pressure of a fixed
volume of gases was
proportional to the number
of atoms present
Molecules
Failure of Dalton’s atomic theory
2 H + O = 2 HO
2 H + O = H2O (does not agree with volume measured)
H + O = HO (does not agree with volume measured)
Avogadro(1775-1856 ): natural units (for chemical reactions are
molecules rather than single atoms.
1 vol. O2 + 2 vol. H2  2 vol. H2O
2 CO (g) + O2 (g)
Avogadro’s number = 6.0221367e23 molecules mol-1 (physical
constant)
1895 , Roentgen, X-ray
Causing the sheet to glow was a penetrating
form of radiation. He called this unknown
radiation X-rays.
penetrating rays could reveal the
internal structure of opaque objects
Crookes tube
Dec.22, 1895
1896 , Becquerel, the discovery of radioactivity
The uranium salt produced an intense silhouette of
itself on the photographic plate
Marie and Pierre Curie
1898, named the emissions (alpha
& beta) from uranium
radioactivity
Discovered the chemical elements
radium and polonium
18
1897, Thomson, the discovery of electron
Atom, was in fact divisible and
contained “smaller parts.”
“plum pudding”model
the atom was a distributed
positively charged mass with an
appropriate number of tiny
electrons embedded in it
1911, Rutherford, nuclear model of the atom
a tiny central positive core that
contained almost all the atom’s
mass. The nucleus was surrounded
by electrons in appropriate number
to maintain a balance of electrical
charge.
"It was as incredible as if you fired a
15-inch shell at a piece of tissue
paper and it came back and hit you."
Radioactivity
Ernest Rutherford
determined there were
3 kinds of radioactivity
1932, Chadwick discovered the neutron
complete the basic model of the
nuclear atom: a central,
positively charged nucleus
containing protons and neutrons
that was surrounded by a
discretely organized cloud of
orbiting electrons.
neutron-related nuclear research
http://www2.lucidcafe.com/lucidcafe/library/library.html#science
1.
人类寻找物质构造基本单元的历
程
>10-2 cm(?)
10-8 cm
10 -12 cm
10-13 cm
Nuclide
Z
N
A
Symbol
碳-12
6
6
12
12C
碳-13
6
7
13
13C
碳-14
6
8
14
14C
?
Atomic and Nuclear Stucture
l
Atom - smallest unit of a chemical element
F
F
n
Nucleus –
F
F
F
F
F
F
F
25
Size on the order of 10-8 cm (1 Angstrom)
Contains Z electrons (Qe = -1e, me = 0.511 MeV/c2)
– e = 1.602x10-19 Coulomb
– and
Size on the order of 10-13 cm (1 Fermi )
Contains more than 99.9% of the mass of the atom
Made of Z protons and N neutrons
Proton (Qp = +1e, mp = 938.28 MeV/c2 )
Neutron (Qn = 0, mn = 939.57 MeV/c2 )
A = Atomic mass = Z + N
Held together by strong nuclear force
 ~ 2.3  1014 g/cm3
A
ZXN where X = chemical symbol
Nobel Prizes in Nuclear Science
Chapter 1. Introduction and Basic concepts
1.The Significance of Nuclear Technology
2.Early Discoveries
3.Basic Facts and Definitions
4.Units
SI system, Physical constants, natural unit
5.Nuclear Reactions
Discovery of nuclear reactions (n.r.).
Energy in n.r.
Neutron induced nuclear reactions
Simple theories or concepts related to n.r.
Types of n.r.
Applications of n.r.
1.3 Basic Facts and Definitions
1) The nucleus and its constituents
2) Nuclear Nomenclature
Nuclide核素: a term used to refer to a particular atom or
nucleus with a specific neutron number N and atomic
(proton) number Z.
Isotopes同位素: atoms of the same element with different
number of neutron
isobar同量异位素: nuclides with the same mass number A =
N + Z but with different number of neutrons N and
protons Z.
Isotone同中子异位素: nuclides with the same number of
neutrons N but different number of protons Z.
isomer同质异能素 : the same nuclide (same Z and N) in
which the nucleus is in different long lived excited
states.
nuclear
jargon
Z
N
A
Examples
isotope
isotone
Same
D
D
Same
D
D
1H
2H
2H
3He
isobar
isomer
D
Same
D
Same
Same
Same
3H
3He
3H
99Te 99mTe
Calculation of Hydrogen Atomic Weight
Isotope
atomic mass
Abundance
1H
1.00782503 0.99985
2H
2.014102
3H
3.016049
0.000148
Trace
atomic mass abundance
1.007674
0.000298
Atomic weight for H = 1.007674 + 0.00298 = 1.007972
•
一些放射性同位素
40
39
K (93.2%)
K
1.28x108 a
•
59Co
60Co
5.27 a
•
88Sr
90Sr
28.8 a
•
127I
131I
8.04 d
•
133Cs
137Cs
30.12 a
Are the chemical properties of isotopes nearly identical?
Stable Nuclides
Stable nuclides remain the same for an indefinite period.
Some characteristics of stable nuclides:
Atomic number Z  83, but no stable isotopes for Z = 43 and 61.
There are 81 elements with 280 stable nuclides.
Usually there are more neutrons than protons in the nuclei.
Nuclides with magic number of protons or neutrons are very stable.
Pairing of nucleons (spin coupling) contributes to nuclide stability.
Is abundance of a nuclide related to its stability?
Stable Nuclides
number of neutrons and protons
Z = # of protons
Find
N / Z for
4He2
=1
16O8 =
40Ar18 =
91Zn40 =
144Nd60 =
186Re75 =
209Bi83 =
N = # of neutrons
Stable Nuclides
N/Z of some light nuclides
Z
Stable Nuclides
| (Magic numbers and double magic-number nuclides are in bold)
21
20 . . . . . . . . . . . . . .
19
18
17
16
15 . . . . . . . . . . . . . .
14
13
12
Mg Mg
11
Na
10 . . . . . . . . . . Ne Ne Ne
9
F
8
O O O
7
N N
6
C C
.
5 . . . .
B B
4
Be
.
3
Li Li
2
He He
.
.
1 P D
0 1 2 3 4 5 6 7 8 9 10 11 12 13
(to be continued)
.
.
.
S S
P
Si Si Si
Al
Mg .
.
.
Ar
Cl
S
Ca
K K
Ar
Cl
S
Sc
Ca Ca Ca
K
Ar
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
Ca
Ca
N
14 15 16 17 18 19 20 21 22 23 24 25 26 27
Stable Nuclides
N/Z of nuclides
N / A ratio increases as
A increases
More stable isotopes
for even Z than odd Z
More stable isotones
for even N than odd N
More stable isotopes
and isotones for magic
Z and N
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
Zr . . . . . . . . + . . . XXX X X
Y
X
Sr
X XXX
Rb
X X
Kr
X X XX X
Br . . . . . + . .
X X
Se
XXXX X X
As
X
Ge
X XXX X
.
Ga
X X
Zn . . . + . X XXX X
.
Cu
X X
Ni
X XXX X
.
.
Co
X
Fe
X XXX
.
.
Mn +
X
Cr
X XXX
.
.
v
XX
Ti XXXXX .
.
.
Sc X
Ca X X
2
2 3
4
5
01234567890123456789012345678901
Stable Nuclides
natural occurring heavy nuclides
Natural Occurring Isotopes of Heavy Elements (abundance)
76
77
78
79
80
81
82
83
Os
Ir
Pt
Au
Hg
Tl
Pb
Bi
184 (0.018), 186 (1.59), 187 (1.64), 188 (13.3), 189 (16.1), 190 (26.4), 192 (41.0)
191 (38.5), 193 (61.5)
190 (0.0127), 192 (0.78), 194 (32.9), 195 (33.8), 196 (25.2), 198 (7.19)
197 (100)
196 (0.146), 198 (10.02), 199 (16.84), 200(23.13), 201(13.22), 202(29.8), 204(6.85)
203 (29.5), 205 (70.5)
204 (1.4), 206 (25.1), 207 (21.7), 208 (52.3)
209 (100)
90
Th
232 (100% half life 1.4x1010 y)
92
U
235 (0.720, half life 7.04x108 y), 238 (99.276, half life 4.5x109 y)
Two protons or neutrons occupy a
quantum state, due to their ½ spin.
Pairing nucleons stabilises nuclides,
leading to a large number of stable
nuclides with even Z and N.
No stable isotopes for Z = 43 or 61.
No stable isotones with N = 19, 31,
35, 39, 61, 89
More stable isotopes for even Z than
odd Z and for even N than odd N
Elements with even Z are more
abundant than those with odd Z of
comparable mass.
Stable Nuclides
pairing of nucleons
Effect of Paring Nucleons
Z
even
even
odd
odd
N
# of stable
stable nuclides
even
166
odd
57
even
53
odd
*4
total
280
*They are: 2D1, 6Li3, 10B5, & 14N7
Stable Nuclides
magic numbers of nucleons
Magic numbers are 2, 8, 20, 28, 50, 82, and 126.
Double-magic number nuclides: 4He2, 16O8, 40Ca20, 48Ca20, & 208Pb82.
4He2
as alpha particles, abundant in the universe,
16O8 abundant on Earth.
Six stable isotopes of Ca20, 5 stable isotopes of Ni28, high for their masses.
Large number of stable isotopes and isotones with Z & N = 50 and 82.
The heavies stable nuclide 209Bi83 has 126 neutrons.
O8, Ca20, Ni28, Sn50 and Pb82 have relative high abundance.
3) Nuclear mass and energy
M( Z , A)  ZM (1H )  ( A  Z )mn  M ( Z , A)
The binding energy (BE) of a nuclide is the energy released when the atom
is synthesized from the appropriate numbers of hydrogen atoms and neutrons.
Z H + N n = AE + BE
The more the binding energy,
the more stable is the nuclide.
or Z mH + N mn = mE + BE
where mH, mn, and mE are masses of H, n, and AE respectively.
Eg
BE = Z mH + N mn - mE
BE (3He) = (2*1.007825 + 1.008665 - 3.01603) 931.481 MeV = 7.72 MeV
BE (4He) = (2*1.007825 + 2*1.008665 - 4.00260) 931.481 MeV = 28.30 MeV
Stable and Radioactive Nuclides
average binding energy
The binding energy and average
binding energy of some nuclides
Nuclide
3He2
4He2
16O8
56Fe26
54Fe26
208Pb82
238U92
BE
MeV
7.72
28.3
127.6
492.3
471.76
1636.44
1801.7
BE / A
MeV / nucleon
2.57
7.08
7.98
8.79
8.74
7.87
7.57
Variation of the Average Binding Energy
as a Function of Mass Number A
BE
BEa
A
Fe
v
U
3
He
A
The Average Binding Energy Curve
Stable and Radioactive Nuclides
a semi-empirical equation for BE
Proportional
to A
Instability
due to p
Pairing of
nucleon
2
2
20
(
A

2
Z
)
0
.
6
Z
BE(A,Z) = 14.1A - 13A2/3 + Ea
1/ 3
A
A
Decrease
due to
surface
tension
Instability
due to
neutron to
proton ratio
Stable and Radioactive Nuclides
mass excess (ME)
The difference between the
mass of a nuclide and its mass
number, A, is the mass excess
(ME),
ME = mass - A.
What are the MEs for the
nuclides listed here?
Which is the standard?
Which have negative MEs?
Masses (amu) of some entities
H
1.00782503 18O 17.99916
2D
2.014102 54Fe 54.938296
3H
3.016049 56Fe 55.934939
4He 4.002603 206Pb 205.975872
12C 12.000000
209Bi 208.9804
14C 14.003242
235U 235.043924
16O 15.994915
238U 238.055040
Stable and Radioactive Nuclides
mass excess (ME) and average -BE
Comparison of mass excess and average binding energy (amu)
Nuclide
Mass
H 1.007825
n 1.008665
3He
3.01603
4He
4.00260
12C 12.000000
16O 15.994915
40Ca 39.96259
54Fe 53.939612
56Fe 55.934939
208Pb82 207.976627
238U92 238.050784
ME
0.007825
0.008665
0.01603
0.00260
0
-0.005085
-0.03741
-0.060388
-0.065061
-0.023373
0.050784
-BE average BE
0
0
-0.00276
-0.0076
-0.00825
-0.00857
-0.00917
-0.00938
-0.00944
-0.00845
-0.00813
0
0
0.00828
0.0304
0.09894
0.1369
0.3669
0.5065
0.52851
1.757
1.934
Stable and Radioactive Nuclides
fission and fusion energy and ME
Variation of ME with A
for Some Stable Nuclides
ME amu
3He
0.01
n
0.005
0.0
H
4He
–0.005
U
12C
Fe
Pb
A
Stable and Radioactive Nuclides
application of mass excess (ME)
Like masses, the ME can be used to calculate energy of decay,
because the same scale is used for both.
eg:
ME’s of 40Sc21 and 40Ca20 are -20.527 and -34.847 MeV respectively.
Estimate the energy of decay for
40Sc21

40Ca20
+ b+ or
40Sc21
+ e– 
40Ca20
solution:
Edecay = -20.527 - (-34.847) = 14.32 MeV
Edecay includes 1.02 MeV for the positron-electron pair for b+ decay.
Chapter 1. Introduction and Basic concepts
1.The Significance of Nuclear Technology
2.Early Discoveries
3.Basic Facts and Definitions
4.Units
Grammar, SI system, Physical constants, natural unit
5.Nuclear Reactions
Discovery of nuclear reactions (n.r.).
Energy in n.r.
Neutron induced nuclear reactions
Simple theories or concepts related to n.r.
Types of n.r.
Applications of n.r.
1.4 Units
1) Grammar
Capitalization
A unit name is never capitalized
even if it is a person's name. Thus
curie, not Curie. However, the
symbol or abbreviation of a unit
named after a person is capitalized.
Thus Sv, not sv.
Space
Use 58 m, not 58m .
plural
A symbol is never pluralized. Thus
8 N, not 8 Ns or 8 Ns .
raised dots
Sometimes a raised dot is used when
combining units such as N.m2.s; however, a
single space between unit symbols is
preferred as in N m2 s.
Solidis
For simple unit combinations use g/cm3 or
g cm-3. However, for more complex
expressions, N m-2 s-1 is much clearer than
N/m2/s.
mixing
units/names
Never mix unit names and symbols. Thus
kg/s, not kg/second or kilogram/s.
prefix
Never use double prefixes such as μμg; use
pg. Also put prefixes in the numerator. Thus
km/s, not m/ms.
double
vowels
When spelling out prefixes with names that
begin with a vowel, supress the ending vowel
on the prefix. Thus megohm and kilohm, not
megaohm and kiloohm.
Hyphens Do not put hyphens between unit names. Thus
newton meter, not newton-meter. Also never
use a hyphen with a prefix. Hence, write
microgram not micro-gram.
numbers For numbers less than one, use 0.532 not .532.
Use prefixes to avoid large numbers; thus
12.345 kg, not 12345 g. For numbers with
more than 5 adjacent numerals, spaces are
often used to group numerals into triplets; thus
123 456 789.123 456 33, not
123456789.12345633.
2) SI system
"International System of Units“
(1) Base units
(2) derived units which are combinations of the
base units,
(3) supplementary units
(4) temporary units which are in widespread use
for special applications.
(5) Special Nuclear Units
(1) Base units
Physical quantity
Unit name
Symbol
length
meter
m
mass
kilogram
kg
time
second
s
electric current
ampere
A
thermodynamic temperature kelvin
K
luminous intensity
candela
cd
quantity of substance
mole
mol
(2) derived units
(3) supplementary units
(4) special applications
(5) Special Nuclear Units
The Electron Volt
1 eV= 1.602 176 46 x 10-19 J
is the kinetic energy gained by an electron (mass me
and charge -e) that is accelerated through a potential
difference ΔV of one volt. The work done by the electric
field is -eΔV = (1.60217646 x 10-19 C)(1 J/C) =
1.60217646 x 10-19 J = 1 eV.
The Atomic Mass Unit 1 amu = 1.6605387 x 10-27 kg
1/12 the mass of a neutral ground-state atom of 12C.
3) Physical constants
4) Natural Units
Units such as meter, second, joule, calorie,
gram, kilogram etc are artificial (man-made)
units.
The fundamental components of materials are called the
natural units.
remain the same during changes
Atoms, electrons, molecules, and moles are natural units or building
blocks of matter. Photons are natural units of EM radiation (energy).
Earth
Water
Cold
Wet
Dry
Hot
Fire
Air
Chapter 1. Introduction and Basic concepts
1.The Significance of Nuclear Technology
2.Early Discoveries
3.Basic Facts and Definitions
4.Units
5.Nuclear Reactions
Discovery of nuclear reactions (n.r.).
Energy in n.r., Experimental
Neutron induced nuclear reactions
Simple theories or concepts related to n.r.
Types of n.r.
Applications of n.r.
1.5 Nuclear Reactions
She points it to the rock, and
the rock turns into gold.
- a legend
Energy drives all reactions, physical, chemical, biological, and nuclear.
Physical reactions change states of material among solids, liquids,
gases, solutions. Molecules of substances remain the same.
Chemical reactions change the molecules of substances, but identities
of elements remain the same.
Biological reactions are combinations of chemical and physical
reactions.
Nuclear reactions change the atomic nuclei and thus the identities of
nuclides. They are accomplished by bombardment using subatomic
particles or photons.
200Hg
+ 1H  197Au + 4He
Discoveries of Nuclear Reactions
In 1914, Marsden and Rutehrford saw some thin tracks and spots
among those due to a particles. They attributed them to protons and
suggested the nuclear reaction:
"the nitrogen atom is
14N
+ 4He 
27Al
(a, n) 30P ( , b+ or EC) 30Si, half life of 30P is 2.5 min
17O
+ 1H or
14N
(a, p)17O disintegrated under the
intense force developed
in a close collision with a
swift particle".
F. Joliot and I. Curie discovered the reaction
a and thin proton spots
on fluorescence screen
a source & tracks with
long & thin proton track
Smashing the Atoms
In 1929, John Cockroft and Ernest Walton used 700,000 voltage to
accelerate protons and bombarded lithium to induce the reaction,
7Li
+p 2a
They called it smashing the atoms, a mile stone in the discovery of
nuclear reaction. This reaction is also a proton induced fission, and
illustrates the stability of the helium nuclide.
They received the Nobel prize for physics in 1951.
Use the discover of n.r. to explain n.r.
Nuclear Reactions
changing the hearts of atoms
Nuclear reactions, usually induced by subatomic particles a, change
the energy states or number of nucleons of nuclides.
After bombarded by a,
the nuclide A emits a
subatomic particle b,
and changes into B.
a
a+A B+b
or written as A (a,b) B
Describe nuclear reactions
b
A (a,b) B
A
B
Subatomic Particles for and from
Nuclear Reactions
Subatomic particles used to bombard
or emitted in nuclear reactions:
g
b
p or 1H
n
d or 2D
t or 3T
a or 4He
nE
photons
electrons
protons
neutrons
deuterons
tritons
alpha particles
atomic nuclei
Endothermic reactions require
energy.
exothermic reactions release
energy.
The Potential Energy of a Positively Charged
Particle as it Approaches a Nucleus.
Potential
Energy of
Nuclear
Reactions
Potential Energy
Coulomb
barrier
Neutron
Charged
particle a
Explain interaction of
particle with nuclei
Nucleus, A
Estimate Energy in Nuclear Reactions
The energy Q in a reaction A (a, b) B is evaluated according to
ma + mA = mb + mB + Q,
where mi means mass of i etc
Q = ma + mA - (mb + mB)
(difference in mass before and after the reaction)
The Q is positive for exothermic (energy releasing at the expense of
mass) or negative for endothermic (requiring energy) reactions.
For endothermic reactions, the energy can be supplied in the form of
kinetic energy of the incident particle. Energy appear as kinetic energy
of the products in exothermic reactions.
Endothermic and Exothermic Reactions
These two examples illustrate endothermic and exothermic reactions.
Example: Energy for the reaction
14N
+
4He
 17O +
1H
+ Q
14.00307 + 4.00260 = 16.99914 + 1.007825 + Q
Q = 14.00307 + 4.00260 – (16.99914 + 1.007825) = – 0.001295 amu
= – 1.21 MeV
endothermic, kinetic energy of a must be greater than 1.21 MeV
Example: The energy Q for the reaction 11B(a, n) 14N, given
masses: 11B, 11.00931; n, 1.0086649.
Q = 11.00931 + 4.00260 - (1.0086649 + 14.00307) = 0.000175 amu
= 0.163 MeV
exothermic reaction
Nuclear Reaction Experiments
A Setup for Nuclear Reactions
Data collection and analysis system
Basic Components
Detectors
particle source
target
shield
detectors
data collection
data analysis system
Particle
source
or
accelerator
Shield
Target
Neutron Sources for Nuclear Reactions
Neutrons are the most important subatomic particles for inducing
nuclear reactions. These sources are:
Neutrons from a induced nuclear reactions
Neutrons from g-photon excitations
Neutrons from nuclear reactions induced by accelerated particles
Neutrons from spontaneous and n-induced fission reactions
(nuclear reactors)
Know how to get neutrons
Neutrons from a Induced Reactions
The discovery of neutron by James Chadwick in 1932 by reaction
9Be
(a, n) 12C,
was applied to supply neutrons for nuclear reactions by mixing aemitting nuclides with Be and other light nuclides.
Mixtures used as neutron sources
Source
Ra & Be
Po & Be
Pu & B
Ra & Al
Reaction
9Be(a,
n)12C
9Be(a, n)12C
11B(a, n)14N
27Al (a, n)31P
n energy / MeV
up to 13
up to 11
up to 6
Neutrons by g Excitation
High-energy photons excites light nuclides to release neutrons. To avoid
a- and b-ray excitation, radioactive materials are separated from these
light nuclides in these two-component neutron sources to supply low
energy neutrons for nuclear reactions.
Two-component neutron sources
Source
Reaction
226Ra,
Be
226Ra, D O
2
9Be(g,
0.6
0.1
24Na,
9Be(g,
0.8
0.2
Be
24Na, H
n)12C
2D(g, n)1H
n energy / MeV
n)8Be
2D(g, n)1H
Neutrons from Accelerators and Reactors
Neutrons are produced from nuclear reaction using energetic
particles from accelerators.
2D
(d, n) 3He
3T
(d, n) 4He
Neutrons from nuclear fission reactions
252Cf
235U
spontaneous fission to yield 3 or more neutrons
and 239 Pu induced fission reactions release 2 to 3
neutrons in each fission
Neutron Induced Radioactivity
Using neutrons from the reaction, 27Al (a, n)31P, Fermi’s group in
Italy soon discovered these reactions:
(n, a) 16N
27Al (n, a) 24Na ( , b) 24Mg.
19F
They soon learned that almost all elements became radioactive
after the irradiation by neutrons, in particular
10B
(n, a) 7Li releasing 2.3-2.8 MeV energy
is used in classical neutron detectors. Now, detectors use,
3He
(n, p) 3H
Application of neutrons
Nuclear Reactions Induced by Cosmic Rays
Cosmic rays consist of mainly high energy protons, and they interact
with atmospheres to produce neutrons, protons, alpha particles and
other subatomic particles.
One particular reaction is the production of 14C,
14N(n,
p)14C - b emitting, half-life 5730 y
Ordinary carbon active in exchange with CO2 are radioactive with 15
disintegration per minute per gram of C.
Applying decay kinetics led to the 14C-dating method.
Simple Theories on Nuclear Reactions
Theories on nuclear reactions involve theory of nuclei, collision
theory, and high-energy particles etc.We can only talk about some
simple concepts of nuclear reactions.
Energy Consideration of Nuclear Reactions
Cross Sections of Nuclear Reactions
Rate of Nuclear Reactions
Types of Nuclear reactions
Give an overall look at n.r.
Nuclear Reaction Cross Sections
Cross section with unit
barn (1 b=1e-28 m2)
comes from target area
consideration, but it is a
parameter ()
indicating the
probability leading to a
reaction,
Cross Section of the Target and
the Random Target Shooting
(Don’t be too serious about the crossection)
rate =  N I
(number per unit time)
N is the number of target
nuclei per unit area;
I is the beam intensity
Differentiate the concept and reality of cross section
Cross Sections and Rate
A large copper (65Cu) foil with a surface density of 0.01g cm-2 is
irradiated with a fast neutron beam with an intensity 2.0e10 n s-1 cm-2.
A total width of the beam is 0.5 cm-2. After irradiation for 1 min, a total
of 6.0e7 64Cu has been formed. Estimate the cross section for the
reaction, 65Cu (n, 2n) 64Cu. Ignore the (t1/2 12.7 h) 64Cu nuclei
decayed during the irradiation.
Solution: ( rate =  N I )
rate = 6e7/60 =1e6 64Cu s-1.
N = 6.022e23*0.01 cm-2*0.5 cm2/ 65 = 9.26e19 65Cu.
1e6 s-1 =  * 9.26e19 * 2.0e10 s-1 cm-2
 = 1.08e-24 cm2 = 1.08 b
The cross section is 1.08 b for 65Cu (n, 2n) reaction.
Cross Sections and Rate
The cross section for neutron capture of cobalt is 17 b. Estimate the
rate of nuclear reaction when 1.0 g of 59Co is irradiated by neutrons
with an intensity of 1.0e15 n s-1 cm-2 in a reactor.
Solution:
In a nuclear reactor, the entire sample is bathed in the neutron flux.
N = 6.022e23 *1.0 / 59 = 1.02e22 59Co
rate =  N I
= 17e-24 * 1.02e22 * 1.0e15 = 1.74e14 60Co s-1
Estimate the radioactivity of 60Co, half life = 5.27 y.
Theories of
Energy Dependence of Cross Section
A Typical Variation of Neutron Cross
Section against the Energy of Neutrons.
Cross sections depend
on the nuclide, the
reaction, and energy.
Cross
section
The neutron capture
cross sections usually
decrease as energy of
the neutron increase.
Energy of n
Theories of
The sharp increases are
due to resonance
absorption.
Cross Sections of Multi-reaction Modes
Reactions of 4He and
209Bi serve as an
example of multiple
reaction modes.
The variation of
partial s as
functions of energy of
4He is shown to
illustrate the point.
Cross Section of Multiple Reaction Modes
Cross
section
 for
209
Bi(a, n)212At
 for
209
Bi(a, 2n)211At
Fragmentation
total = Si
for total consumption
of nuclei.
a particle energy
Effective Cross Section (mb) of Fusion Reactions
10000
1000
Nuclear Fusion
Cross Sections
D + T  4He + n
Cross sections data from
reactions studied using
particles from cyclotron
100
D + D  3T + p
10
7Li
(p, n) 7Be
3T (p, n) 3He
1H (t, n) 3He
2D (d, n) 3He
2D (t, n) 4He
3T (d, n) 4He
D + D  3He + n
1.
D + 3He  4He + p
0.1
10
20
30
40
50
60
60
keV
Types of Nuclear Reactions
Elastic scattering (n, n) no energy transfer
Inelastic scattering (n, n) energy transferred
Capture reactions (n, g)
Photon excitation (g, )
Rearrangement reactions (n, x)
Fission reactions
Fusion reactions
Theories of
Elastic and Inelastic Scattering
When the incident and emitted particles are the same, the process is
scattering. If energy is transferred between the particle and the
target nuclei the process is inelastic, otherwise, elastic.
Elastic scattering example:
208Pb (n, n) 208Pb, but the two n’s may not be the same particle
Inelastic scattering examples:
40Ca (a,a) 40mCa
208Pb (12C, 12mC) 208mPb
Types of
excitation
mutual excitation
Capture Reactions
The incident particle is retained by target nuclei in capture
reactions. Prompt and delayed g emission usually follow.
(p, g) 198Hg80
238U (n, g) 239U
2D (n, g) 3T
9Be (n, g) 10Be
12C (n, g) 13C
14N (n, g) 15N
197Au79
Types of
Rearrangement Nuclear Reactions
After absorption of a particle, a nuclide rearranges its nucleons
resulting in emitting another particle. For example:
197Au
(p, d) 196mAu
4He (4He,
p) 7Li
27Al (4He,
n) 30P
54Fe (4He,
2 n) 56Ni
54Fe (4He,
d) 58Co
54Fe (32S, 28Si) 58Ni
Particles or nuclides
Transformation of Nuclides in Nuclear Reactions
No. of protons
(3He, 2n)
(a, 3n)
(3He, n),
(d, b), (a, 2n)
(3He, g)
(a, n), (t, b)
(p, n)
(d, 2n)
(p, g), (n, b)
(3t, 2n), (d, n)
(3He, d)
(a, t)
(d, g)
(3t, n)
(3He, p)
(a, d)
(n, g)
(d, p)
(3t, d)
(3He, 2p)
(a, 3He)
(g, n)
(n, 2n)
(p, d)
(3He, a)
(g, d)
(n, 3t)
(d, a)
Original
Nuclide
Scattering,
elastic & inelastic
(g, p)
(3t, a)
(n, p)
(d, 2p)
(3He, 3p)
(a, g)
(3t, g)
(a, p)
(3t, p)
(a, 2p)
(3t, 2p)
(a, 3p)
No. of neutrons
Types of
Some
Nuclear
Reactions
Nuclear Fission and Fusion
A nuclide splits into two pieces with the emission of some
neutrons is nuclear fission. Nuclides such as 254Fm undergo
spontaneous fission, whereas neutrons induce 238U and 239Pu
fission.
Fusion on the other hand combines two light nuclides into one,
and may also be accompanied by the emission of one or more
nucleons. An important fusion is
2D
+ 3T  4He + n
Applications of Nuclear Reactions
Based on nuclide productions:
synthesis of radioactive nuclides - for various applications
synthesis of missing elements Tc, Pm and At
synthesis of transuranium (93-102) elements
synthesis of transactinide (103 and higher) elements
Activation analyses
non-destructive methods to determine types and amounts of
elements
Applications of
Syntheses of Radioactive Isotopes
Over 1300 radioactive nuclides have been made by nuclear reactions.
The most well known is the production of 60Co, by neutron capture,
59Co
(100%) (n, g) 60mCo and 60Co - b and g emission t1/2 = 5.24 y
The sodium isotope for study of Na transport and hypertension is
produced by
23Na
(n, g) 24Na (b emission, t1/2 = 15 h)
For radioimmunoassay, 131I is prepared by
127I
(n, g) 128I (b,b EC, t1/2 = 25 m)
There are many other production methods.
Applications of
Syntheses of Tc, Pm, and At
In 1937, Perrier and Segré synthesized the missing element 43 using
deuteron from cyclotron,
96Mo
+ 2D 
97Tc
+ n, (Tc, EC, t1/2 = 2.6e6 y)
In 1940, Segré and Mackenzie synthesized and named element 85
astatine ( Greek astatos - unstable) At by the reaction,
209Bi83
(a, xn) (213-x)At85, (x = 1, 2, 3 etc)
The missing element promethium was made by
144Sm62
(n, g) 145Sm ( , EC) 145Pm61 (EC, t1/2 = 17.7 y)
Many more isotopes of these elements have been made.
Applications of
Syntheses of Transuranium Elements
From 1940 to 1962, about 11 radioactive transuranium elements (almost 100
nuclides) have been synthesized, about one every two years. Representative
isotopes of the 11 elements are neptunium (Np93), plutonium (Pu94),
americium (Am95), curium (Cm96), berklium (Bk97), californium (Cf98),
einsteinium (Es99), fermium (Fm100), mendelevium (Md101), nobelium (No102),
and lawrencium (Lw103).
La57 , Ce, Pr59, Nd, Pm61, Sm, Eu63 , Gd, Tb65 , Dy, Ho67, Er, Tm69, Yb, Lu71
Ac89, Th, Pa91, U92, Np93 , Pu , Am95, Cm, Bk97, Cf, Es99, Fm, Md, No, Lw103
Among these, tons of 239Np, and its decay products 239Pu have been made for
weapon and reactor fuel. Successive neutron capture reactions are major
methods, but accelerators are involved. . . continue =>
Applications of
Syntheses of Transuranium Elements -continue
Very heavy elements are synthesized using accelerated nuclides,
246Cm
+ 12C 
252Cf
+ 10B 
252Cf
+ 11B 
254No102
+ 4 n,
247Lw103
+ 5 n,
247Lw103
+ 6 n.
These syntheses completed the analogous of rare-earth elements.
These elements were made during the cold war, and results from the
former USSR were not available to us.
Applications of
Syntheses of Transactinide Elements
242Pu (22Ne,
4n) 260Rf104
249Cf98 (12C6, 4n) 257Rf104
249Cf (15N, 4n) 260Ha105
249Cf (18O, 4n) 263Sg106
268Mt109 ( , a) 264Ns107
209Bi (55Mn, n) 263Hs108
208Pb (58Fe, n) 265Hs108
272E111 ( , a) 268Mt109
208Pb (64Ni, n) 271Uun110
209Bi (64Ni, n) 272Uuu111
Applications of
rutherfordium
hahnium
seaborgium
nielsbohrium
hassium
meitnerium
ununnilium
unununium
Elements with Z > 103 are
transactinides. Some
results from both the USA
and the former USSR are
known, and some of the
syntheses are given here.
Neutron Activation Analyses (NAA)
Since most elements capture neutrons and produce radioactive
isotopes, these reactions made them detectable.
After b emission, the daughter nuclides usually emit g rays. Each
nuclide has a unique g-ray spectra. Presence of their spectra
after irradiation implies their being in the sample, and Intensities
of certain peaks enable their amounts to be determined.
NAA has many applications, and these will be discussed in
Chapter 12.
Applications of
Neutron Activation Analyses (NAA)
NAA can be applied to explore planets and satellites and other
objects in space.
Detectors
Applications of
Particle
gun
Summary
Discovery of nuclear rreactions (n.r.).
Energy in n.r.
Neutron induced nuclear reactions
Simple theories or concepts related to n.r.
Types of n.r.
Applications of n.r.