Lecture 1: RDCH 702 Introduction

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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

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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

research

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Grading• Homework (25 %)

§ Weekly homework questions§ Develop tools for research (spreadsheets)

• Two exams (30 % each)§ Oral exam§ 30 minutes each

à 1st exam on question from course informationà 2nd exam on literature

• Classroom participation (15 %)§ Bring chart of the nuclides!

• Class developed to assist and compliment research activities

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Chart of the Nuclides• Presentation of data on nuclides

§ Information on chemical element§ Nuclide information

à Spin and parity (0+ for even-even nuclides)à Fission yield

§ Stable isotopeà Isotopic abundanceà Reaction cross sectionsà Mass

• Radioactive isotope§ Half-life§ Modes of decay and energies§ Beta disintegration energies§ Isomeric states§ Natural decay series§ Reaction cross sections

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Chart of Nuclides

• Decay modes§ Alpha§ Beta§ Positron § Photon§ Electron capture§ Isomeric transition§ Internal conversion§ Spontaneous fission§ Cluster decay

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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)

à Electrons can be excited* Higher energy orbitals* Ionization

Ø Binding energy of electron effects ionization§ Isotopes

à Same Z different N§ Isobar

à Same A (sum of Z and N)§ Isotone

à Same N, different Z§ Isomer

à Nuclide in excited state à 99mTc

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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

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X-rays• Removal of K shell electrons

§ Electrons coming from the higher levels will emit photons while falling to this K shellà series of rays (frequency n

or wavelength l) are noted as Ka, Kb, Kg

à If the removed electrons are from the L shell, noted as La, Lb, Lg

• In 1913 Moseley studied these frequencies n, showing that:

• 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

Kb La

Ka

(a)

l

2 2 1 1 0

2 2 1 1 0

1 1 0

0

j

5/2 3/2 3/2 1/2 1/2

5/2 3/2 3/2 1/2 1/2

3/2 1/2 1/2

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E(keV)

0,077 0,079 0,151 0,164 0,231

0,728 0,741 0,990 1,056 1,215

5,014 5,360 5,706

35,974

(b)

valeurs de l(A;°)

valeurs de l(A;°)

valeurs de l( A;°)

Lg1 2,34723 La2 2,90145 Kb1 0,35434 Lb4 2,66587 La1 2,89193 Ka2 0,40482 Lb3 2,63521 L 2,98932 Ka1 0,40026 Lb2 2,51146 Ll 3,26618 Lb1 2,68321 Kb2 0,34608

O

N

M

L

K

)ZZ(A on

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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

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Fundamentals of x-rays

• X-rays§ X-ray wavelengths from 1E-5 angstrom to

100 angstromà De-acceleration of high energy electronsà Electron transitions from inner orbitals

* Bombardment of metal with high energy electrons

* Secondary x-ray fluorescence by primary x-rays

* Radioactive sources* Synchrotron sources

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1. a decay (occurs among the heavier elements)

2. b decay

3. Positron emission

4. Electron capture

5. Spontaneous fission

Types of Decay

EnergyRnRa a42

22286

22688

EnergyXeI nb13154

13153

EnergyNeNa nb2210

2211

EnergyMgAl nb 2612

2613

EnergynRuXeCf 10

10844

14054

25298 4

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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

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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

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Fundamental Forces

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Classic and relativistic

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Use of relativistic terms

• relativistic expressions• photons, neutrinos• Electrons > 50 keV• nucleons when the

kinetic energy/nucleon exceeds 100 MeV

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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

à 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

2h

p/

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Wavelengths

• Photon relationships

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Particle Physics

• fundamental particles of nature and interaction symmetries

• Particles classified as fermions or bosons§ Fermions obey the Pauli principle

à antisymmetric wave functions à half-integer spins

* Neutrons, protons and electrons à Bosons do not obey Pauli principle

* symmetric wave functions and integer spinsØ Photons

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Particle physics

• Particle groups divided § leptons (electron) § hadrons (neutron and

proton)à hadrons can

interact via the strong interaction

à Both can interact with other forces

à Fermionic Hadrons comprised of quarks