501503742 nuclear and radiation physics

Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh).

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501503742 Nuclear and Radiation Physics

Before we start, let us tackle the following:

• Why nuclear physics?• Why radiation physics?• Why in Jordan?• Interdisciplinary.• Applied.

Nuclear Physics at BAU http://nuclear.bau.edu.jo/

This coursehttp://nuclear.bau.edu.jo/nuclear-radiation/


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General subjects to be covered

This phenomenological course provides the launch point for other nuclear physics courses that will follow.

This is an introductory course that will cover the following general subjects

• Nuclear properties.• Binding energy and nuclear stability.

• Nuclear models.• Spin and moments.

• Nuclear forces.• The structure of the nucleus.

• Nuclear reactions: energetics and general cross-section behavior.• Neutron moderation, fission, controlled fission and fusion.

• Radioactive decays.• Interactions of nuclear radiations (charged particles, gammas, and neutrons) with

matter.


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Level Test

1.Write down whatever you know about nuclear spin.

2.Describe how can either fission or fusion produce energy.

3.What is …1.Compton scattering?2.Energy straggling?3.Annihilation?4.Neutron activation?5. Isotopes, Isotones, Isobars, Isomers?6.Parity.


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Grading

Mid-term Exam 25%Project, quizzes and HWs 25%Final Exam 50%

• Homeworks are due after one week unless otherwise announced.• Remarks or questions marked in red without being announced as homeworks should be also seriously considered!• Some tasks can (or should) be sent by email:

[email protected]


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Proposed Projects• Experiments to determine nuclear properties.• Nuclear power generation.• Nuclear medicine.• Health physics.• Accelerator driven systems.• Nucleosynthesis.• Technological applications (e.g. Material Science).• Radioactive ion beams.• Neutrino physics.• Radiological dating.• Environmental radioactivity.• ….. (your own selected subject).

Decide on the title of your project within two weeks. Due date (for written version): December 6th. Presentation: Will be scheduled later.


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Scale and ObjectivesDimensional scale: Order of magnitude of 1 x 10-15 m 1 femtometer 1 fm 1

fermi.Too small for direct investigation.What about time and energy scales?

We need to answer …..1. What are the building blocks

of a nucleus?2. How do they move relative to

each other?3. What laws governing them?We need to understand:• Nuclear forces (Q2, Q3).• Nuclear structure (Q2, Q3).

We also need High Energy Physics (to answer Q1).


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http://physics.nist.gov/cuu/Constants/index.html

Constants


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Nomenclature

NAZ X

Element vs. Nuclide.94 natural chemical elements, total > 100.Element Atomic number (Z) chemically identical.~3000 nuclides……? How many are stable?Same Z but different neutron number (N) Isotopes.Total number of nucleons = Z+N = A mass number.

XA 112211Na Na23 Na24

Radioactive Stable Radioactive

Same mass number Isobars chemically dissimilar, parallel nuclear features (Radius …). decay.Same neutron number Isotones ?????.Same Z and same A Isomers metastable.Stable isotope (Isotopic) Abundance.Radioactive isotope Half-life.

XAm

Chart of N

uclides

Chart of N

uclides

redundant

C:\Program Files\NuChart\NUCHRT.exe


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Stable Isotopes

HWc 1HWc 1

Odd A Even A

Isotope N Z N Z

Then plot Z vs. N.Odd A Even A


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Properties Structure

The energy of the nucleon in the nucleus is in the order of 10 MeV.

HW 1HW 1 Calculate the velocity of a 10 MeV proton and show that it is almost 15% of the speed of light. (Perform both classical and relativistic calculations). Relativistic effects are not important in considering the motion of nucleons in the nucleus.

HW 2HW 2 Calculate the wavelength of a 10 MeV proton and compare it with the nuclear scale. (Perform both classical and relativistic calculations). Is the nucleus thus a classical or a quantum system?

HW 0HW 0 Krane, Ch. 2. HW 3HW 3 Calculate the wavelength for an electron of the same energy to show that it is much too large to be within the nucleus. (Perform both classical and relativistic calculations). Discuss the proton-electron nuclear hypothesis!

Basic Nuclear Properties

Chadwick, neutron.


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Basic Nuclear PropertiesStatic nuclear properties (Time-independent):Electric charge, radius, mass, binding energy, angular momentum, parity, magnetic dipole moment, electric quadrupole moment, energies of excited states.Dynamic properties (Time-dependent):• Self-induced (Radioactive decay).• Forced (Nuclear reactions) cross sections. .

The key: Interaction between individual nucleons.

Excited states: atomic intervals ~ eV.nuclear intervals ~ 104 – 106 eV.

Decays and reactions: Conservation laws and selection rules.

HWc 2HWc 2 Where to find nuclear data???


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Nuclear Mass (Introduction)

• Unified atomic mass unit u based on 12C.• Replaced both physical and chemical amu based on 16O and natural oxygen, respectively (Find conversion factors).• 1 u = M(12C)/12 = ……… kg = …………… MeV/c2.• Rest masses

u MeV/c2 kgelectron ………… …………… ………proton ………… …………… ………neutron ………… …………… ………12C 12 …………… ………

• Avogadro’s number .. !! What is the number of atoms in 1 kg of pure 238U?• Mass Stability. E = mc2. Tendency towards lower energy Radioactivity. • Neutron heavier than proton “Free” neutron decays (T½ = ???):

_

epn


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Nuclear Mass (Introduction)

• Nuclear masses measured to high accuracy:• mass spectrograph.• energy measurement in nuclear reactions.

• Mass decrement = difference between actual mass and mass number:Δ = m – A

• http://www.eas.asu.edu/~holbert/eee460/massdefect.html• Negative Δ mass into energy.• Binding Energy?• Stability?• Fission?• Fusion?

• More later ……..

Usually atomic masses are tabulated. Mass of the atom < ZmH + Nmn.


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The Valley of Stability

501503742 nuclear and radiation physics

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