Radiation Physics and Instruments (RIRP202)

Radiation Physics and Instruments (1)

• Course code: RIRP202
• First Semester-2025
• Lecturer: Prof.Dr. Yasser Rammah

Lecturer 1

• Date: 01.10.2024
• Topic: Radiation and Atom

What is Radiation?

• Radiation is energy traveling through space.
• Sunshine is a common form of radiation.
• Radiation delivers energy, light, heat, and suntans.
• Exposure to radiation is controlled.
• Higher-energy radiation types are used in medicine.
• Ionizing radiation, from space, air, and Earth, exists in low doses.
• Ionizing radiation can damage matter, especially living tissue.
• Controlling exposure to radiation is essential due to its potential danger at high levels.

The Atom

• All matter is made of atoms.
• Atoms are the smallest components of an element.
• Atoms comprise protons, neutrons, and electrons.
• Atoms are mostly empty space.
• Protons and neutrons reside in the nucleus.
• The number of electrons equals the number of protons.
• Electrons orbit the nucleus.
• Atoms are extremely small
• A teaspoon of water has more atoms than teaspoons of water in the Atlantic Ocean

Particle Properties of Atoms

• Protons have a positive charge.
• Neutron has a neutral charge.
• Electrons have a negative charge.
• Proton Mass: 1.672 × 10⁻²⁷ kg, Energy: 938.2 MeV
• Neutron Mass: 1.675 × 10⁻²⁷ kg, Energy: 939.2 MeV
• Electron Mass: 0.911 × 10⁻³⁰ kg, Energy: 0.511 MeV

Standard Nuclear Notation

• Mass number (A) = number of protons (Z) + number of neutrons (N)
• Example: 12C6, 13C6, 14C6

Let's Practice

• 1H has 1 proton.
• 7Li3 has 4 neutrons.
• 17O8 has 8 protons
• 1H1 has 0 neutrons.

The Nucleus

• Nucleons include protons and neutrons
• Atomic number (Z) is the number of protons in a nucleus.
• Mass number (A) is the total number of protons and neutrons.
• Isotopes are atoms with the same atomic number, but different mass numbers.
• Nuclide refers to each unique atom

Atomic Mass Units (AMU)

• Atomic masses can be in grams or relative numbers (unified atomic mass units, u).
• One mole of a substance contains 6.02 x 10²³ molecules (Avogadro's number)
• The mass of one mole in grams is numerically equal to the molecular weight.
• One atom of 12C has an atomic mass of exactly 12 u (by definition)
• One AMU (u) = 1.6605 × 10⁻²⁴ kg

Electromagnetic Wave

• Electromagnetic waves have wavelength, period, and amplitude.
• The propagation velocity of electromagnetic waves is c

Electromagnetic Spectrum

• The spectrum details electromagnetic waves by wavelength, frequency,and energy.
• Types of Electromagnetic radiation include Radio waves, Infrared, Visible light, Ultraviolet, and X- and gamma rays.
• Different wavelengths correspond to different radiation types with different applications

Ionizing vs. Non-Ionizing Radiation

• Ionizing radiation has enough energy to remove electrons from atoms, while non-ionizing does not.

Why is it called Ionizing?

• Ionizing radiation creates charged atoms (ions).

Penetration Abilities

• Different types of radiation penetrate matter to varying degrees. (Alpha, Beta, Gamma, X-rays, Neutrons).
• Alpha particles have low penetration
• Beta particles have medium penetrations
• Gamma and X-rays have high penetration.
  • Neutrons have high penetrating power

Inverse Square Law for Radiation

• Intensity of radiation decreases with the square of the distance from the source.

Properties of Ionizing Radiation

• Strength or radioactivity
• Energy of radiation
• Level of radiation in the environment
• Radiation dose

Units of Radiation

• Radiologic units include Roentgen, Rad, Rem, Curie, and Electron Volt.

Roentgen (R)

• A unit of dose or intensity of electromagnetic radiation.
• 1 R creates 2.08 × 10⁹ ion pairs in 1 cm³ of air
• Units of charge per unit mass of air: 1 R = 2.58 × 10−4 C/kg

Rad

• A unit of absorbed dose of radiation.
• 1 rad means 1 gram of material absorbs 100 ergs of energy (100 ergs/g = 10⁻² Gy).
• The gray (Gy) is the SI unit for absorbed dose

Rem

• A unit of dose equivalent, used for occupational exposure.
• 1 sievert is equivalent to 100 rem.

Curie (Ci)

• A unit for the decay rate of radioactive material.
• One Curie is 3.7×10¹⁰ atoms disintegrating per second.

Electron Volt (eV)

• A unit of energy, equivalent to the energy gained by an electron moving across an electric potential difference of 1 volt.
• 1 eV = 1.602 × 10⁻¹⁹ J .

Practical Units (Absorbed Dose)

• Gray (Gy) is the SI unit.
• 1 Gy= 100 rad
• Dose measured in J/kg

Equivalent Dose

• Expresses the biological effect of a radiation dose.
• Equivalent dose is measured in sieverts (Sv).
• 1 Sv = 100 rem
• 1mSv = 100mrem

Effective Dose

• Takes into account the sensitivity of different tissues to radiation.
• Measured in sieverts (Sv).

This quiz covers key concepts in Radiation Physics, focusing on the nature of radiation and atomic structure. Learn about different radiation types, their applications in medicine, and the fundamental components of atoms. Test your understanding of these crucial topics in the first semester of the course.