Uses of Radioactivity | Chemistry for EmSAT Achieve PDF Download

Applications of Radioactivity

Radioactivity is utilized in various ways across different fields, including:

• Medical Procedures: Radioactive materials are employed in medical procedures for both diagnosis and treatment of diseases, particularly cancer.
• Food Sterilization: Radioactive radiation is used to sterilize food products, a process known as food irradiation. This helps eliminate bacteria, insects, and parasites, extending the shelf life of the food.
• Sterilizing Medical Equipment: Radioactive sources are utilized to sterilize medical equipment, ensuring it is free from harmful microorganisms and safe to use in healthcare settings.
• Age Determination of Ancient Artefacts: Radioactive dating methods, such as carbon dating, are used to determine the age of ancient artefacts and archaeological samples by measuring the decay of radioactive isotopes present in them.
• Thickness Measurement: Radioactive sources, particularly gamma radiation, find application in industrial settings to measure the thickness of materials. This is achieved by analyzing the attenuation of the radiation as it passes through the material.

Smoke Detectors

• Smoke detectors utilize alpha particles. The emitted alpha radiation typically ionizes the air inside the detector, creating an electric current. When smoke enters the detector, it obstructs the alpha emitter, disrupting the current. This change is detected by a microchip, triggering the alarm.
• The selection of the specific type of radiation to use in a particular application depends on the unique properties and characteristics of each type, such as its ability to penetrate materials and its ionizing capability.

In the diagram on the right, alpha particles are stopped by the smoke, preventing the flow of current and triggering the alarm

Thickness Measurement of Materials

To measure the thickness of materials, a method involving a beta source and a detector is commonly employed. Here's how it works:

• Beta Source and Detector Setup: A beta radiation source is positioned on one side of the material, while a detector is placed on the opposite side. The beta particles emitted by the source can penetrate the material.
• Particle Monitoring: As the material moves above the beta source, the detector monitors the number of beta particles that are able to pass through and reach it.
• Thickness Variation: If the material becomes thicker, more beta particles will be absorbed or blocked, resulting in fewer particles reaching the detector. On the other hand, if the material becomes thinner, more particles will pass through and reach the detector.
• Adjustment for Constant Thickness: Based on the detected number of particles, the measurement system can make adjustments to ensure that the thickness of the material remains constant. For example, if the detected particle count decreases, indicating an increase in thickness, appropriate actions can be taken to adjust the manufacturing process and maintain the desired thickness.

By continuously monitoring the penetration of beta particles through the material, this method enables real-time adjustments to ensure consistent thickness. It finds applications in industries where precise control of material thickness is crucial, such as in manufacturing processes involving films, coatings, and sheet materials.

Beta particles can be used to measure the thickness of thin materials such as paper, cardboard or aluminium foil

Uses of Different Types of Radiation

The choice of using beta radiation, alpha particles, or gamma radiation depends on their specific properties. Here's how they are utilized:

• Beta Radiation: Beta radiation is preferred for thickness measurement because it is partially absorbed by the material. This allows the monitoring of particle penetration to determine thickness. If alpha particles were used, they would be completely absorbed, while gamma radiation would mostly pass through, making it difficult to detect thickness variations.

Diagnosis and Treatment of Cancer:

• Radiotherapy: Radiotherapy is the application of radiation to treat cancer. While radiation can cause cancer, it is also highly effective in destroying cancer cells. Gamma rays, which can penetrate the body, are directed at the cancerous tumor. The beams of gamma rays are carefully moved to minimize harm to healthy tissue while targeting the tumor.
• Tracers and PET Scans: Tracers, radioactive isotopes, can be used to track the movement of substances like blood in the body. Positron Emission Tomography (PET) scans can detect emissions from the tracer, aiding in cancer diagnosis and locating tumors within the body.

Chemotherapy, on the other hand, refers to cancer treatment using chemicals. Radiation therapy plays a vital role in the effective treatment of cancer, as it can selectively target and destroy cancer cells that are more susceptible to radiation compared to healthy cells. PET scans utilizing tracers help in diagnosing cancer and precisely locating tumors in the body.

Sterilising Food and Medical Equipment

• Gamma radiation is widely used to sterilise medical equipment
• Gamma is most suited to this because:
• It is the most penetrating out of all the types of radiation
• It is penetrating enough to irradiate all sides of the instruments
• Instruments can be sterilised without removing the packaging
• Food can be irradiated in order to kill any microorganisms that are present on it
• This makes the food last longer, and reduces the risk of food-borne infections

Food that has been irradiated carries this symbol, called the Radura. Different countries allow different foods to be irradiated