Ionizing and Non-ionizing Radiation

 

The key difference between ionizing radiation and non-ionizing radiation lies in their energy levels and their ability to ionize atoms or molecules.

  • Ionizing radiation has enough energy to remove tightly bound electrons from atoms, creating ions.

  • Non-ionizing radiation does not have enough energy to remove electrons from atoms. It primarily causes excitation or vibration of atoms and molecules.

Both types of radiation must be managed appropriately to minimize risks to health and the environment.

Characteristics of Ionising Radiation

High-energy radiation with photon energy greater than 10 electron volts (eV). Such radiation may have enough energy to break down the bonds between atoms and molecules.

Causes ionization, which can damage living cells and DNA. Can lead to cell death or mutations, increasing cancer risk.

  • Examples: X-rays; Gamma rays; Alpha particles; Beta particles; Neutrons.

  • Applications: medical imaging (X-rays, CT scans); cancer treatment (radiation therapy); sterilization and food preservation.

  • Effects: Prolonged or high exposure can cause serious health effects, including DNA damage, radiation sickness and cancer.

Characteristics of Non-ionising Radiation

Lower-energy radiation with photon energy less than ~10 eV. Can excite atoms and molecules but does not break down their bonds and ionise them (hence, non-ionising radiation).

Can cause significant heating (e.g., microwaves heat food).

  • Examples: electric and magnetic fields (EMF); radio waves; microwaves; infrared (IR); visible light; ultraviolet (UV) (although higher-energy UV can ionize), lasers.

  • Applications:communication (radio, TV, mobile phones, lasers); heating (microwaves, IR); lighting (e.g., visible light); medical (UV for sterilization, IR for therapeutic heating).

  • Effect: Typically, less harmful than ionizing, but prolonged exposure (such as UV light or high-power microwaves) can cause heating resulting in localized tissue damage (to skin or eyes) or other health issues.

For the purposes of radiation safety, non-ionising radiation is broken into a number of broad types:

  • Electric and Magnetic Field(EMF): 0-100 kHz. Low-level electromagnetic radiation arising from the delivery of domestic electrical power across transmission lines and its distribution, as well as some workshop and laboratory equipment.

  • RF radiation: 100 kHz to 300 GHz. Electromagnetic waves that do not ionize atoms or molecules. Its frequency range spans from very low frequencies to the visible spectrum.

  • Radio Waves: 100 kHz to 300 GHz. Includes AM/FM radio, TV broadcasts, mobile communications.

  • Microwaves: 300 MHz to 300 GHz. Used in radio-relay communications, satellite communications, radar, microwaves.

  • Lasers: 300 GHz to 30 EHz. Lasers are highly coherent and monochromatic light.

  • Infrared (IR) Lasers: ~300 GHz - ~430 THz (700 nm to 1 mm). Examples: CO₂ (10.6 µm), Nd:YAG lasers (1064 nm), fibre lasers, and telecom lasers (1550 nm).

  • Visible Light Lasers: ~430 to ~750 THz (400 nm to 700 nm). Examples: Helium-neon (633 nm), argon-ion (488 nm and 514 nm), and GaN diode lasers for blue, green and red light.

  • Terahertz Lasers (Far Infrared): ~0.1 to ~10 THz (30 µm to 3 mm). Free-electron lasers (FELs) and quantum cascade lasers.

  • Ultraviolet (UV) Lasers: ~750 THz to ~30 PHz (10 nm to 400 nm). Examples: Excimer lasers, frequency-doubled solid-state lasers (e.g., Nd:YAG at 355 nm.

  • X-ray Lasers: ~30 PHz to ~30 EHz (0.01 nm to 10 nm). Examples: Free-electron X-ray lasers.

  • Infrared Radiation (IR): 300 GHz to 430 THz. Emitted by heat sources and used in remote controls and thermal imaging.

  • Visible Light: 430 THz to 750 THz. The visible spectrum.

  • Ultraviolet Radiation (UV): 750 THz to 30,000 THz (or 30 PHz). Approximately 400 nanometres (nm) down to 10 nanometres (nm). Commonly used in industrial curing, sterilization/disinfection, counterfeiting detection, and medical phototherapy. Extreme UV frequencies possess enough energy to ionize atoms.

edVirtus Radiation Safety Courses

edVirtus radiation safety courses cover ionizing radiation, specifically RF radiation and lasers.

RF Radiation Safety: Our radiation safety course cover level 1 and level 2 qualifications:

Laser Safety. Our laser safety courses provide appropriate levels of understanding of the principles of laser safety practice to meet the needs of Australian/International standards for laser safety officers, laser safety supervisors, and laser users/operators and maintainers. If you are not sure which laser safety course suits you, please see our guide to choosing the right course.