Frequently Asked Questions on Radiation

A General FAQ on Natural and Man-made Radiation

Radiation is a natural and widely studied phenomenon that plays a crucial role in various fields, including medicine, industry, energy production, and scientific research.

1. What is radiation?

Radiation is the emission and transmission of energy in the form of waves or particles through space or a material medium. It can be natural (such as sunlight and cosmic rays) or man-made (such as X-rays and nuclear radiation).

Radiation is broadly classified into non-ionizing radiation and ionizing radiation, based on its energy levels and effects on matter.

2. What are the different types of radiation?

Radiation comes in several forms, each with different properties and levels of penetration. The four main types are alpha, beta, gamma, and neutron radiation, all of which interact with matter in unique ways.

Alpha radiation consists of heavy particles made up of two protons and two neutrons. It is relatively weak in penetration and can be stopped by a sheet of paper or even human skin. However, if inhaled or ingested, alpha radiation can cause severe internal damage, making it one of the more dangerous forms of radiation in certain scenarios. It is commonly found in radon gas and radioactive materials like uranium and plutonium.

Beta radiation consists of high-energy electrons or positrons, which are much lighter than alpha particles. It can penetrate deeper into materials, passing through the skin and causing burns, though it is generally stopped by plastic, glass, or a few millimetres of aluminium. Beta radiation is used in various industrial and medical applications, including radiocarbon dating and certain cancer treatments.

Gamma radiation is a form of high-energy electromagnetic radiation, similar to X-rays but far more powerful. Unlike alpha and beta radiation, gamma rays have no mass or charge, allowing them to penetrate deeply into materials and human tissue. Shielding requires dense materials such as lead or concrete. Due to its penetrating ability, gamma radiation is used in medical imaging, cancer therapy, and industrial inspections, but it also poses significant external health risks if exposure is not properly controlled.

Neutron radiation, unlike the others, consists of uncharged particles. It is highly penetrating and can pass through most materials, including lead, which is ineffective as a shield. Instead, neutron radiation is best absorbed by hydrogen-rich materials such as water, polyethylene, or concrete. This type of radiation is commonly found in nuclear reactors, particle accelerators, and nuclear weapons. A unique danger of neutron radiation is its ability to make surrounding materials radioactive, a process known as neutron activation.

Each type of radiation presents different risks, requiring appropriate shielding and safety measures to prevent harmful exposure. Understanding their properties helps industries, healthcare professionals, and safety regulators protect workers and the public from potential hazards.

3. Where can you find Radiation?

Radiation is present everywhere—in nature, in the human body, and in various industries. It can come from natural sources or be produced by human activities.

In an industrial setting, radiation is often produced as a byproduct of processes or as part of essential equipment. Industries typically use radiation for imaging, measurement, and energy production, requiring strict safety measures to protect workers and the environment.

Common sources of radiation in industrial environments include:

• Nuclear power plants for generation of electricity – typically found in nuclear fuel, reactor cores and spent fuel storage facilities.
• Medical and healthcare facilities – radiopharmaceuticals are used in diagnostic treatments and therapy, whilst x-ray machines, CT scanners both use ionizing radiation.
• Oil and Gas drilling - Naturally Occurring Radioactive Materials (NORM) are often exposed during drilling operations
• Mining and mineral processing - Uranium and other radioactive elements occur naturally in certain ores, with workers prone to exposure of radon gas and radioactive dust,
• Industrial radiography and non-destructive testing (NDT) – The use of gamma or X-rays is used to inspect welds, pipelines, and metal structures.
• Aerospace and defence - radiation is used in spacecraft power systems (radioisotope thermoelectric generators - RTGs), whilst typical defence applications include radar systems, and nuclear-powered submarines.
• Research and academic institutions - universities and laboratories use radioactive materials for scientific research.

4. What are the most common ways of detecting radiation?

To ensure the safety of personnel and surroundings in industrial, medical, and nuclear environments, it is essential to detect and monitor radiation. Various instruments are used to identify and measure radiation levels, helping to prevent overexposure and contamination. The best detection method ultimately depends on the type of radiation, the level of sensitivity required and whether or not you are trying to monitor individuals and their exposure or a wider area/environment.

One of the most widely used radiation detectors is a Geiger-Müller (GM) Counter, which can detect alpha, beta, and gamma radiation by measuring ionization in a gas-filled tube.

Alternatively, Scintillation Detectors use special materials (e.g. sodium iodide) that emit light when struck by radiation. These are more sensitive than GM counters, especially for gamma rays and are used in medical imaging, environmental monitoring, and security screening.

Dosimeters are personal radiation monitors worn by workers in high-risk environments. They include film badges, thermoluminescent dosimeters (TLDs), and electronic dosimeters, but all dosimeters will measure cumulative radiation exposure over time to ensure safety limits are not exceeded.

Ionization chambers measure radiation by detecting ion pairs produced in a gas-filled chamber. They are highly accurate and used for high-radiation environments, such as nuclear power plants or for radiation therapy calibration in hospitals.

Semiconductor detectors use materials like silicon or germanium to detect radiation with high precision. Commonly used for gamma-ray spectroscopy to identify specific radioactive isotopes.

Neutron detectors are specialised instruments that detect neutron radiation, often found in nuclear reactors and research facilities.

Contamination monitors are designed to detect surface contamination by radioactive particles, and are typically found in nuclear plants, laboratories, and decontamination procedures.

Airborne radiation monitors can detect radon gas and airborne radioactive particles in the environment – these are typically found in mining, nuclear facilities, and environmental surveying situations.

5. What’s the difference between a Geiger counter and a personal radiation detector?

Both devices are crucial for radiation safety, but they serve different roles in detection and protection. You would typically use a Geiger counter to measure and locate radiation in an environment. A Personal Radiation Device (PRD) would be used if you wanted to monitor an individual's exposure to radiation.