Radiation Physics and Instruments (1) Quiz

Radiation Physics and Instruments (1)

• Course: Radiation Physics and Instruments (1)
• Semester: First Semester 2025
• Course Code: RIRP202
• Lecturer: Prof. Dr. Yasser Rammah

Radiation

• Radiation is energy traveling through space.
• Sunshine is a common form of radiation.
• Radiation delivers energy, light, heat, and suntans.
• People control their exposure to radiation.
• Higher-energy radiation is used in medicine.
• People are exposed to low doses of radiation from space, air, and earth.
• Collectively, these kinds of radiation are called ionizing radiation.
• Ionizing radiation can damage matter, especially living tissue.
• High levels of ionizing radiation are dangerous and require controlled exposure.

The Atom

• All matter is made up of atoms.
• Atoms are the smallest components of an element and are made up of three particles:
• Protons
• Neutrons
• Electrons
• The atom is mostly empty space.
• Protons and neutrons are located in the nucleus.
• The number of electrons is equal to the number of protons.
• Electrons orbit the nucleus.
• Atoms are extremely small; a teaspoon of water contains many more atoms than teaspoons found in the Atlantic Ocean.

Standard Nuclear Notation

• Mass number (A) = number of protons (Z) + number of neutrons (N)
• Atomic number (Z) = number of protons
• Chemical symbol (X)

Let's Practice

• Examples of determining the number of protons and neutrons in various atoms are shown.

The Nucleus.

• Nucleons are particles found in the nucleus of an atom.
• Protons are positively charged particles.
• Neutrons have no electrical charge.
• Atomic number (Z) = number of protons
• Mass number (A) = number of protons + neutrons
• Isotopes are atoms with same atomic number (Z) but different mass numbers (A).
• Nuclide refers to each individual unique atom.

Atomic Mass Unit (AMU)

• Atomic masses can be expressed in grams or unified atomic mass units (u).
• One mole of any substance contains 6.02 x 10²³ molecules (Avogadro's number).
• The mass in grams of one mole is equal to the molecular weight of the substance.
• The mass of a single atom can be calculated.
• For example, for 12C, 1 mole is 12g.

Atomic Structure

• Diagram showing the structure of an atom (nucleus and electrons in shells).

Fundamental Particles

• Table listing fundamental particles (protons, neutrons, electrons, positrons, alpha particles) with their symbols, relative charge, mass (amu), and approximate energy equivalent (MeV).

Definitions

• Isotopes: Nuclei with same atomic number (Z) but different number of neutrons, hence different mass numbers.
• Nucleon: A particle inside the nucleus (either a proton or a neutron).
• Nuclide: A specific nucleus with given numbers of protons and neutrons.
• Isobars: Nuclei with the same mass number (A) but different atomic numbers (Z).
• Isotones: Nuclides with the same number of neutrons.
• Isomers: Nuclides with same atomic number (Z) and mass number (A) but differing energy states; they remain in excited states longer than 10-5 sec.
• Mirror Nuclei: Nuclides with same mass number (A) where the proton number (Z) in one equals the neutron number (N) in the other.

Binding Energy

• Binding energy is the energy required to separate a particle from a system or disperse all particles in a system.
• Binding energy depends on the shell and the atomic number.
• The energy increases as the atomic number increases.

Electromagnetic Waves

• Equations for energy, frequency, and wavelength showing the relationship.
• Diagram of an electromagnetic wave showing the amplitude, wavelength, and propagation velocity.

Electromagnetic Spectrum

• Table of the electromagnetic spectrum listing different types of electromagnetic radiation: radio waves, infrared, visible light, ultraviolet, X-rays, gamma rays with wavelength, frequency, and energy values.
• Diagram showing the electromagnetic spectrum with the types of radiation ordered from longest to shortest wavelength. The spectrum ranges from non-ionizing to ionizing radiation.

Ionizing vs. Non-Ionizing Radiation

• Non-ionizing radiation is radiation that isn't energetic enough to remove electrons from atoms or molecules.
• Ionizing radiation is radiation that has sufficient energy to remove electrons from atoms or molecules.
• Examples of ionizing radiation: alpha, beta, gamma, X-rays, and neutrons.

Why is it called ionizing?

• Ionizing radiation creates ions (atoms with a charge) by removing electrons from atoms.

Penetration Abilities

• Different types of radiation have different penetrating abilities.
• Alpha particles have the lowest penetrating ability.
• Beta particles have higher penetrating ability than alpha particles.
• Gamma rays have the highest penetrating ability.

Inverse Square Law for Radiation

• The intensity of radiation decreases with the square of the distance from the source.

Properties Considered When Ionizing Radiation Measured

• The strength or radioactivity of the source.
• The energy of the radiation.
• The level of radiation in the environment.
• The radiation dose (absorbed energy).

Units of Radiation

• Roentgen (R): Unit of exposure for electromagnetic radiation.
• Rad: Unit of absorbed dose measures energy deposited by radiation in a material.
• Rem: Unit of dose equivalent.
• Curie (Ci): Unit of radioactivity, measures the decay rate of radioactive material.
• Electron Volt (eV): Unit of energy associated with the movement of an electron across an electric potential difference of one volt.
• Gray (Gy): International System unit of absorbed dose.

Practical Units

• Ionizing radiation penetrates human bodies and deposits energy.
• Absorbed dose: The amount of energy deposited per kilogram of material.
• Gray (Gy): The SI unit for absorbed dose.
• Rad: The traditional unit for absorbed dose.

Equivalent Dose

• Equivalent dose considers the type of radiation and its effect on tissue.
• Sievert (Sv): The SI unit for equivalent dose.

Effective Dose

• Effective dose accounts for the different sensitivities of various organs to radiation.