NuSc 341Introduction to Radiochemistry

(and Nuclear chemistry)

John D’Auria

Instructor: John D’Auria (Professor Emeritus)Office: ???Telephone: At SFU - ???

At TRIUMF - 604 222 7337E-Mail: dauria@sfu.ca (preferred method of comm.)Web page: http://www.sfu.ca/NuSc344.htmOffice hours: ???Also you are automatically member of email list nusc341-d1@sfu.ca

Useful Web pagehttp://www.nndc.bnl.gov/index.jsp

Some GuidelinesSome Guidelines

Lectures: M,W,F 8:30-9:20, AQ5018Tutorial: Th 8:30-9:20, AQ5018 (not regularly)Books: “Radiochemistry and Nuclear Methods of Analysis” by Willian D. Ehman & Diane E. Vance

OR “Modern Nuclear Chemistry” by Walter Loveland, Dave Morrissey and Glen Seaborg

2 Midterm Exams: October 12 and November 13,Final Exam: Mid December 9, Final Grade: 60% final; 20% midterm 1; 20%; midterm 2

Course Outline Topic # Lectures

First 4 weeks -Introduction to material/basics 1 -Properties of the nucleus 6 -Radioactive Decay 2 -Kinetics of decay 2

First mid-term test Fri, 12th Oct (tentative)...50 min (20%) Next four weeks

-Interactions of radiation with matter (3)-Radiation detection (3)-Health Physics (1)-Nuclear reactions (2)-Accelerators and Reactors (2)

Second mid-term test Mon. Nov 13th (tentative)...50 min (20%) Final weeks Applications

-Nuclear dating-Origin of the elements-Nuclear techniques-Topics related to nuclear phenomena (Muonic

atoms, muonium and positronium chemistry, -Nuclear Medicine and others).

Final Exam...3 hours Wed 9th December, 8:30 – 11:30, room#?? (60%) Visit to TRIUMF (needs to be scheduled)

Other Useful BooksJeff Bryan, Introduction to Nuclear Science, 2008, CRC Publishing Co.

G.Friedlander & al., Nuclear and Radiochemistry, all editions 3th ed., 1981 Wiley. G.R. Choppin & J. Rydberg, Nuclear Chemistry, Theory and Applications (1980) Pergamon Press. O. Navrátil ... [et al.]. Nuclear chemistry New York : E. Horwood, 1992. Karl Heinrich Lieser, Nuclear and radiochemistry : fundamentals and applications, 2nd ed. Berlin ; New York : Wiley-VCH, 2001. B.L. Cohen, Concepts of Nuclear Physics (1971) McGraw-Hill Pub. Co. G.R. Choppin, Nuclei and Radioactivity (1964), W.A. Benjamin Pub. Co. M. Haissinsky, Nuclear Chemistry and its applications, (1964) Addison-Wesley. B.G. Harvey, Introduction to Nuclear Physics and Chemistry (1962) Prentice-Hall. Choppin, Gregory R., Jan-Olov Liljenzin, and Jan Rydberg. Radiochemistry and nuclear chemistry 3rd ed., Oxford ; Boston : Butterworth-Heinemann, 2002 Adloff, J-P & Guillaumont R., Fundamentals of Radiochemistry, CRC Press 1993

Nuclear Science MinorThe Program in Nuclear Science

Nusc 341 Introduction to Radiochemistry 342 Introduction to Nuclear Science

344 (or Phys. 390) Nucleosynthesis and Distribution of the Elements

346 Radiochemistry Laboratory 444 Special Topics in Nuclear Science 485 Particle Physics 481/482 Directed Studies

FacultyChemistry – Corina Andreoiu, Kris Starosta, Physics – Mike Vetterli, Duggan O’Neil,

Howard Trottier, Bernd Stelzer

What is in the Universe?What is in the Universe?

What is Nuclear Science?What is Nuclear Science?Nuclear science: study of structure, properties, and interactions of atomic nuclei at fundamental level.

nucleus – contains almost all mass of ordinary matter in a tiny volume understanding behavior of nuclear matter under normal conditions

and conditions far from normal a major challenge extreme conditions existed in the early universe, exist now in the core

of stars, and can be created in the laboratory during collisionsbetween nuclei (TRIUMF)

Nuclear scientists investigate by measuring the properties, shapes, and decays of nuclei at rest and in collisions. Radiochemistry: Use chemistry and related techniques to study properties of the nucleus; Use of radiation and radioactivity in chemistry and related fields. Applications: - Nuclear medicine and Radiopharmaceutical chem..

Diagnostic, e.g. PETTherapeutic isotopes (Silver bullet)Radiation Therapy

- Radioanalytical techniquesNAA (Neutron activation analysis)Isotopic Dilution Wet Chemistry

- Environmental RadiochemistryRadon in HomesActivity in snowSmoke detectorsFlying

- Tracer Studies in Bio, Chem, Biochem., etc.- Waste Disposal and Treatment (Reactors)- Homeland security !!!

InteractionsInteractions

forces strength range (fm) exchange particle mass (eV) charge spin Decay

gravitational 6x10-39 infinite graviton? 0 0 2 ?

weak 1x10-6 2x10-3 W±, Z 91x109 ±1,0 1 beta

electromagnetic 7x10-3 infinite photon 0 0 1 gamma

strong 1 1.5 pion 35x106 0 1 alpha

1 fm = 101 fm = 10-15-15 m m

The forces of elementary particle physics are associated with the exchange of particles. The forces of elementary particle physics are associated with the exchange of particles. An interaction between particles is characterized by both its strength and its range.An interaction between particles is characterized by both its strength and its range.

Force between two objects can be described as exchange of a particle – particle transfersmomentum and energy between the two objects, and is said to mediate the interaction

graviton – not yet observedpions or pi mesons – between nucleons

Standard ModelStandard Model

• Attempts to explain all phenomena of particle physics in terms of properties and interactions of a small number of three distinct types.

• Leptons: spin-1/2 (+- e)

• Quarks: spin-1/2• Bosons: spin-1; force carriersThese are assumed to be elementary.

Standard ModelStandard Model

HadronsHadrons

Hadrons: any strongly interacting subatomic particle; composed of quarks.

There are 2 categories:• Baryons: fermions, made of 3 quarks (duu-p)• Mesons: bosons, made of quark, antiquark

AntiparticlesAntiparticles• Electron (e-) – Positron (e+) Particles and antiparticles

(such as the pair highlighted in pink) are created in pairs from the energy released by the collision of fast-moving particles with atoms in a bubble chamber. Since particles and antiparticles have opposite electrical charges, they curl in opposite directions in the magnetic field applied to the chamber.

AntiparticlesAntiparticles

Building BlocksBuilding Blocks

• Molecules consists of atoms.• An atom consists of a nucleus, which carries

almost all the mass of the atom and a positive charge Ze, surrounded by a cloud of Z electrons.

• Nuclei consist of two types of fermions: protons and neutrons, called also nucleons.

• Nucleons consists of three quarks.

e = 1.6022 x 10-19 C

1 fm = 10-15 m

1 Å = 10-10 m

mp = 1.6726 x 10-27 kg = 938.26 MeV = 1.007276 u

mn = 1.6749 x 10-27 kg = 939.55 MeV = 1.008665 u

Charge: e Charge: 0

3 quarksbaryons

The NucleusThe NucleusThe atomic nucleus consists of protons and neutrons

Protons and neutrons are generally called nucleons

A nucleus is characterized by:• A: Mass Number = number of nucleons• Z: Charge Number = number of protons• N: Neutron Number

Of course A=Z+N

Determines the ElementDetermines the Isotope

Usual notation:

12CElement symbol – defined by charge numberC is Carbon and Z = 6

Mass number A

So this nucleus is made of 6 protons and 6 neutrons

MassMass• Nuclear and atomic masses often given in u: atomic mass

unit• 12.000 u = 12 daltons mass of a neutral 12C atom• 1 u = 1.6605 x 10-27 kg• Mass and energy are interchangeable – E = mc2

where energy usually expressed in MeV• 1 MeV = 1.602 x 10-13 J• 1 u = 931.5 MeV/c2

Isotopes: same Z 40Ca, 42Ca, 44Ca [9C—22C particle stable and exist] often, ‘isotope’ used instead of ‘nuclide’ isotopes have same Z, so same number of electrons => same chemistry

use radioactive isotope in place of stable one – can monitordecay for tracer studies

Isotones: same N 40Ca, 42Ti, 44Cr

Isobars: same A 42Ca, 42Ti, 42Cr Isomers: Long lived excited states

Isodiaphors: same neutron excess 42Ca, 46Ti, 50Cr

isodiaphors: same neutron excess, N - Z

11 NA

Z E NAZ E11

1

21

NAZ E

11

NAZYN

AZY1

1

N

AZY

121

NAZ X N

AZ X11

11 N

AZ X

isodiaphors

isotopes

isobars

isotones

Z

Classification of Nuclides Classification of Nuclides • Stable nuclei: 264; 16O• Primary natural radionuclides: 26; very long half-

lives; 238U with T1/2 = 4.47 x 109 y

• Secondary natural radionuclides: 38; 226Ra T1/2 = 1600 y decay of 238U

• Induced natural radionuclides: 10; cosmic rays; 3H T1/2 = 12.3 y; 14N(n,t)12C

• Artificial radionuclides: 2000, 60Co, 137Cs…• 4He++ stripped helium nucleus (1905 – Rutherford)

Properties/Info on nuclear species

Alpha Particle – 4He++ () – stripped helium nucleusIdentified in 1905 by Rutherford who placed a 210Po alpha emitting source in a glass tube. It was evacuated and left for a period of time. Helium gas was then found in the tube.

 Beta: Member of the lepton familyTwo beta particles, namely

- Electron (-,) discovered by J.J. Thomson- Positron (+) discovered by Carl Anderson

 Neutrino: - Member of the lepton family- Predicted by Pauli 1937- Very weakly interacting- Observed in 1953 by Reines and Cowan….How???- Solar neutrino flux studied by SNO….???

Leptons: Interact through the weak forceBehave as point particlesEmitted by nucleus; cannot exist in nucleus  

Gamma Ray - -ray ; photon of high energy (high frequency)masslessmember of EM spectrum

Periodic TablePeriodic Table

Chart of NucleiChart of Nuclei• plot of all known nuclei as a function of Z and N

Chart of Nuclides Chart of Nuclides

http://www.nndc.bnl.gov/chart/

……or Segre Chartor Segre Chart• plot allows various nuclear properties to be understood at a glance, similar to how chemical properties are understood from the periodic chart• ~ 2500 different nuclei known• 270 stable/non-radioactive• theorists guess at least 4000 more to be discovered at higher neutron

numbers, higher mass• limits –• proton-rich side (left of stable): proton dripline cannot add another proton, it

“drips” off dripline is known/accessible to experiments• neutron-rich side (right of stable): neutron dripline cannot add another

neutron, it “drips” off dripline is unknown – neutron-rich nuclei difficult to produce/study

• mass (above stable) – cannot add another proton or neutron limit unknown – again, difficult to produce/study

• “island of stability” predicted near Z = 114; not yet observed

TermsHalf-life – time it takes for ½ of the nuclides to decay - T1/2

Activity

Units  1 – Unit of activity CURIE  Becquerel

  2 – Units of energy   

3 – Units of mass  

4 – Health Physics ( rad, rem, sieverts) Concepts EnergyWork = Force x distance Kinetic energy = ½ x mass x (velocity)2

 Potential energy – energy a body possess by virtue of its position in a field. Coulombic : attractive (repulsion) between unlike (like) charges 

Force = q1 q2/ r2 ; PE = V = force x distance,  

Ions in a magnetic field 

radius of curvature = momentum/charge x magnetic field

  

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B - rigidity =     Relativity

  Decay Scheme

   Heisenberg Uncertainity Principle   

Brief historyRoentgen (X-rays), 1895

(cathode rays struck wall, caused emission of light and X-rays)Becquerel, Natural radioactivity (1896)

(discovered radiation from uranyl sulphate)Curie, isolate more radioactive elementsRutherford, 1903 (proved alphas were helium ion)Rutherford, Geiger and Marden, 1911 (atomic model)Soddy (1913), isotopesChadwick (1932) neutronHahn and Strassman (1938) discover fission (n + U)Fermi – first reactor at Univ. of Chicago, theory of beta decay,+++Seaborg – producing many tranuranic elementsLawrence – the cyclotron