Radiation Physics: Neutron and Particle Types

Neutron Sources

• Neutron generators emit neutrons, D-D reaction ejects neutrons at 2 MeV, D-T reaction ejects neutrons at 14 MeV.
• Neutron fluence rate (N) represents the number of neutrons passing through a specific area per unit time (n/cm²/s).
• Neutron direction is irrelevant when calculating fluence rate.

X-Ray Production

• X-rays are produced when high-energy electrons hit a target.
• High voltage accelerates electrons, which then hit the target, generating X-rays.

Beta Particles

• Beta particles are high-energy electrons or positrons emitted during beta decay.
• Two types of beta decay (β- and β+).
• Beta decay is when an atomic nucleus releases a beta particle.
• Beta particles are a form of radiation.
• Beta particles are negatively or positively charged.
• Examples of beta-emitting isotopes: Ba-137, Cs-137.

Alpha Particles

• Alpha particles are identical to helium-4 nuclei and consist of two protons and two neutrons.
• They are positively charged.
• Alpha decay is when an atomic nucleus releases an alpha particle.
• Alpha decay is one type of radioactive decay.

Radiation

• Radiation is energy traveling through space; it includes the familiar forms of energy like sunlight.
• Radiation transmits energy (sunlight, heat, and light).
• It can harm living tissue.
• It's essential to regulate exposure to high levels of radiation.

The Atom

• Atoms are the building blocks of all matter.
• Atoms are composed of three particles: protons, neutrons, and electrons.
• Protons and neutrons reside in the atom's nucleus.
• Electrons orbit the nucleus.
• Protons have a positive charge, neutrons are neutral, and electrons have a negative charge.

Standard Nuclear Notation

• A is the mass number (number of protons + neutrons)
• X is the chemical symbol
• Z is the atomic number (number of protons)

Particle Properties (Protons, Neutrons, Electrons)

• Protons: positively charged, mass 1.672 x 10⁻²⁷ kg, energy 938.2 MeV.
• Neutrons: neutrally charged, mass 1.675 x 10⁻²⁷ kg, energy 939.2 MeV.
• Electrons: negatively charged, mass 0.911 x 10⁻³⁰ kg, energy 0.511 MeV.

Definitions

• Isotopes: Nuclei with the same atomic number (Z) but different mass numbers (A), because they have varying numbers of neutrons.
• Nucleon: A proton or a neutron, a particle found inside the atom's nucleus.
• Nuclide: A specific nucleus with a specified number of protons (Z) and neutrons (N).
• Isobars: Nuclei with the same mass number (A), but different atomic numbers (Z).

Wave-Particle Duality

• E = mc² : Energy equals mass times the speed of light squared.
• E = hf : Energy equals Planck's constant times frequency.
• c = λf : Speed of light equals wavelength times frequency.
• E = h/λ: Energy equals Planck's constant divided by wavelength.

Binding Energy

• Binding energy is the energy required to separate a particle from a system of particles.
• Binding energy varies based on the atomic number and the shell structure.

Isotones/Isomers/Mirror Nuclei

• Isotones: Nuclei with the same neutron number (N).
• Isomers: Nuclei with the same Z and A, but exist in different energy states.
• Mirror Nuclei: Nuclides with same A, where the number of one particle (proton or neutron) in one nucleus is the same as the other particle's number in the other nucleus.

Ionizing vs. Non-Ionizing Radiation

• Ionizing radiation has enough energy to remove electrons from atoms, damaging matter. Examples: alpha, beta, gamma, x-rays, and neutrons.
• Non-ionizing radiation does not have enough energy to remove electrons. Examples: light, radio waves, microwaves, infrared, visible light, and ultraviolet.

Radiation Units

• Rad (Radiation Absorbed Dose): Measures the energy deposited per unit mass of a material.
• Roentgen (R): Measures the ionization in air due to X-rays or gamma irradiation.
• Rem (Roentgen Equivalent Man): Accounts for the biological effect of different types of radiation.
• Sievert (Sv): The SI unit of dose equivalent, encompassing the biological effects of various radiation types.
• Curie (Ci): Measures the decay rate of a radioactive material.
• Electron Volt (eV): A unit of energy.

Additional Concepts

• The nucleus contains most of the atom's mass.
• A mass number (A) is a sum of the numbers of protons and neutrons.
• An atomic number (Z) is the number of protons in an atom.