Transcript RDCH 702: Introduction

Lecture 1: RDCH 702 Introduction
• Class organization
 Outcomes
 Grading
• Chart of the nuclides
 Description and use of chart
 Data
• Radiochemistry introduction
 Atomic properties
 Nuclear nomenclature
 X-rays
 Types of decays
 Forces
1-1
RDCH 702: Introduction
• Outcomes for RDCH 702
 Understand chemical properties in radiation and
radiochemistry
 Use and application of chemical kinetics and
thermodynamics to evaluate radionuclide speciation
 Understand the influence of radiolysis on the
chemistry of radioisotopes
 Understand and evaluate radioisotope production
 Evaluate and compare radiochemical separations
 Utilization of radioisotope nuclear properties in
evaluating chemical behavior
 Use and explain the application of radionuclides in
research
 Discuss and understand ongoing radiochemistry
1-2
research
Grading
• Homework (25 %)
 Weekly homework questions
 Develop tools for research (spreadsheets)
• Two exams (30 % each)
 Oral exam
 30 minutes each
 1st exam on question from course information
 2nd exam on literature
• Classroom participation (15 %)
 Bring chart of the nuclides!
• Class developed to assist and compliment research
activities
1-3
Chart of the Nuclides
• Presentation of data on nuclides

Information on chemical element

Nuclide information
 Spin and parity (0+ for even-even nuclides)
 Fission yield

Stable isotope
 Isotopic abundance
 Reaction cross sections
 Mass
• Radioactive isotope

Half-life

Modes of decay and energies

Beta disintegration energies

Isomeric states

Natural decay series

Reaction cross sections
1-4
Chart of Nuclides
• Decay modes
 Alpha
 Beta
 Positron
 Photon
 Electron capture
 Isomeric transition
 Internal conversion
 Spontaneous fission
 Cluster decay
1-5
Introduction
•
•
Radiochemistry

Chemistry of the radioactive isotopes and elements

Utilization of nuclear properties in evaluating and understanding chemistry

Intersection of chart of the nuclides and periodic table
Atom

Z and N in nucleus (10-14 m)

Electron interaction with nucleus basis of chemical properties (10-10 m)
 Electrons can be excited
* Higher energy orbitals
* Ionization
 Binding energy of electron effects ionization

Isotopes
 Same Z different N

Isobar
 Same A (sum of Z and N)

Isotone
 Same N, different Z

Isomer
 Nuclide in excited state
 99mTc
1-6
X-rays
• Electron from a lower level is removed
 electrons of the higher levels can come to occupy
resulting vacancy
 energy is returned to the external medium as
electromagnetic radiation
• radiation called an X-ray
 discovered by Roentgen in 1895
 In studying x-rays radiation emitted by uranium
ores Becquerel et. al. (P. and M. Curie) discovered
radioactivity in 1896
1-7
X-rays
•
•
•
•
Removal of K shell electrons

Electrons coming from the
higher levels will emit photons
while falling to this K shell
 series of rays (frequency n
or wavelength l) are
noted as Ka, Kb, Kg
 If the removed electrons
are from the L shell,
noted as La, Lb, Lg
In 1913 Moseley studied these
frequencies n, showing that:
n  A(Z  Zo )
where Z is the atomic number and, A
and Z0 are constants depending on
the observed transition.
K series, Z0 = 1, L series, Z0 = 7.4.
Lg
Lb
O
N
M
Kb
La
Ka
L
K
(a)
l
j
E(keV)
2
2
1
1
0
5/2
3/2
3/2
1/2
1/2
0,077
0,079
0,151
0,164
0,231
2
2
1
1
0
5/2
3/2
3/2
1/2
1/2
0,728
0,741
0,990
1,056
1,215
1
1
0
3/2
1/2
1/2
5,014
5,360
5,706
0
1/2
35,974
(b)
Lg1
Lb4
Lb3
Lb2
Lb1
valeurs de l(A;°
)
2,34723
2,66587
2,63521
2,51146
2,68321
valeurs de l(A;°
)
2,90145
La2
2,89193
La1
2,98932
L
Ll
3,26618
0,34608
Kb2
valeurs de l( A;°
)
0,35434
Kb1
0,40482
Ka2
0,40026
Ka1
1-8
1-9
Absorption Spectra
• Edge
keV
A
• K
115.6061
0.1072
• L-I
21.7574
0.5698
• L-II
20.9476
0.5919
• L-III
17.1663
0.7223
• M1
5.5480
2.2348
• M2
5.1822
2.3925
• M3
4.3034
2.8811
• M4
3.7276
3.3261
• M5
3.5517
3.4908
• N1
1.4408
8.6052
• N2
1.2726
9.7426
• N3
1.0449
11.8657
U absorption edges and scattering coefficients
1-10
Fundamentals of x-rays
• X-rays
 X-ray wavelengths from 1E-5 angstrom to
100 angstrom
De-acceleration of high energy electrons
Electron transitions from inner orbitals
* Bombardment of metal with high
energy electrons
* Secondary x-ray fluorescence by
primary x-rays
* Radioactive sources
* Synchrotron sources
1-11
Types of Decay
1. a decay (occurs among the heavier elements)
226
88
Ra Rn a  Energy
222
86
4
2
2. b decay
131
53

I 131
Xe

b
n  Energy
54
3. Positron emission
22
11
Na Ne  b n  Energy

22
10
4. Electron capture
26
13
Al  b  Mg n  Energy

26
12
5. Spontaneous fission
Cf  Xe Ru 4 n  Energy
252
98
140
54
108
44
1
0
1-12
Half Lives
for the condition: N/No=1/2=e-lt
N=Noe- lt
l=(ln 2)/t1/2
Rate of decay of 131I as a function of time.
http://genchem.chem.wisc.edu/sstutorial/FunChem.htm
1-13
Forces in nature
• Four fundamental forces in nature

All interactions in the universe are the result of these forces
• Gravity

Weakest force

most significant when the interacting objects are massive,
such as planets, stars, etc.
• Weak interaction

Beta decay
• Electromagnetic force

Most observable interactions
• Strong interaction

Nuclear properties
1-14
Fundamental Forces
1-15
Classic and relativistic
1-16
Use of relativistic terms
•
•
•
•
relativistic expressions
photons, neutrinos
Electrons > 50 keV
nucleons when the
kinetic energy/nucleon
exceeds 100 MeV
1-17
Wavelengths and energy
• Planck evaluated minimum from DExDt when he studied the
radiation emitted by a black body at a given temperature
• Quantum called Planck’s constant h (h = 6.6 10-34 J.s).

radiation conveys energy E in the form of quanta E = hn
 n the frequency of the emitted radiation
• Based on the wave mechanics worked out by de Broglie
 l = h/p

l is the wavelength associated with any moving particle with
the momentum p
 /p
h

2
1-18
Wavelengths
• Photon relationships
1-19
Particle Physics
• fundamental particles of nature and interaction
symmetries
• Particles classified as fermions or bosons
 Fermions obey the Pauli principle
 antisymmetric wave functions
 half-integer spins
* Neutrons, protons and electrons
 Bosons do not obey Pauli principle
* symmetric wave functions and integer spins
 Photons
1-20
1-21
Particle physics
• Particle groups divided

leptons (electron)

hadrons (neutron and
proton)
 hadrons can
interact via the
strong interaction
 Both can interact
with other forces
 Fermionic Hadrons
comprised of
quarks
1-22