What are Alpha Rays?
One of the most important discoveries in the field of science was of alpha particles which was done by Ernest Rutherford. When the nucleus of atoms are unstable, they release alpha particles to gain stability, and this process is known as alpha decay. Alpha decay is the main source of the formation of alpha radiations. Some of the examples of elements in which alpha decay takes place are Uranium, Plutonium, etc. They cannot go inside the human’s skin, therefore are harmless for humans externally. They can be stopped even by a thick piece of paper. However, as mentioned earlier, they can cause harm to soft living tissues.
An Alpha Particle Coming out of an Atom
Properties of Alpha Particles
They are positively charged particles.
They are heavy as compared to particles of other radiations.
They are highly energetic and thus use up their energy over short distances and are unable to travel far from the atom.
Their penetrating power (power to go inside an object) is low.
What are Alpha Rays Used for?
Alpha particles are highly energised radiation. Some of their important uses are listed below:
They are used in the treatment of cancer.
They are used in smoke detectors.
They are used in providing power to spacecrafts.
They are used in oil industry.
They are used in medical field to provide power to heart pacemakers.
Heart Pacemaker
Smoke Alarm
Industrial Use of Alpha Rays
It is important to explore where are alpha particles used. Some of their industrial uses are as follows:
They are used to remove static electricity, for example, in paper mills.
They are used in the oil industry to give power to some of their tools.
They are typically used as a source of fuel.
Solved Questions
1. Alpha rays are produced by which type of decay?
Alpha decay
Beta decay
Gamma decay
Ans: Option (a) Alpha decay
2. Alpha rays are used in which of the following gadgets?
Alarm clock
Smoke alarm
Water alarm
Ans: Option (b) Smoke alarm
3. Alpha rays can treat which of the following diseases?
Cancer
Dengue
Pneumonia
Ans: Option (a) Cancer
Summary
Alpha particles are heavy, positively charged, and high energy particles which are produced during alpha decay of heavy atoms. They are used in various fields which benefit humans at an advanced level, for example, it was almost impossible to make a person’s heart beat again after it stopped working once, but today, we have heart pacemakers which turned impossible into reality. Alpha Rays are used as fuel that provides energy to the heart pacemaker. Apart from the medical field, they are used in various other industries.
FAQs on Uses of Alpha Rays
1. What are alpha rays and how are they produced?
Alpha rays are streams of alpha particles, which are essentially helium nuclei (two protons and two neutrons) with a +2 positive charge. They are produced during a process called alpha decay, where an unstable, heavy atomic nucleus, such as that of uranium or radium, ejects an alpha particle to become more stable.
2. What are the key properties of alpha particles?
Alpha particles have several distinct properties:
- High Mass: They are relatively heavy compared to other radiation particles like beta particles or gamma rays.
- Positive Charge: They carry a +2 charge, causing them to be deflected by electric and magnetic fields.
- High Ionising Power: They are highly effective at knocking electrons out of the atoms they pass, which is known as ionisation.
- Low Penetrating Power: Due to their large size and charge, they cannot penetrate materials deeply. They can be stopped by a simple sheet of paper or the outer layer of human skin.
3. What are the main applications of alpha rays in different fields?
Alpha rays have several important applications, including:
- Medical Field: Used in certain types of cancer therapy (Targeted Alpha Therapy) and to power heart pacemakers.
- Industrial Use: Employed in smoke detectors and to eliminate static electricity in industries like paper mills.
- Space Exploration: Used in Radioisotope Thermoelectric Generators (RTGs) to provide a long-lasting power source for spacecraft and rovers.
- Oil Industry: Utilised in tools for exploration and analysis.
4. How do alpha rays work in a household smoke detector?
In a typical ionisation-type smoke detector, a small amount of an alpha-emitting element like Americium-241 is used. The alpha particles it emits ionise the air molecules inside a chamber, creating a small, steady electric current. When smoke particles enter the chamber, they attach to these ions, neutralise them, and disrupt the current. This drop in current triggers the alarm.
5. Why are alpha rays used in specific applications like smoke detectors but considered dangerous if ingested?
This is due to the dual nature of their properties. Their low penetrating power makes them safe externally, as they cannot pass through the skin. This makes them ideal for controlled devices like smoke detectors. However, their high ionising power makes them extremely dangerous if an alpha-emitting substance is inhaled or ingested. Inside the body, they can directly damage the soft tissues and DNA of nearby cells, leading to severe health risks like cancer.
6. How do alpha rays compare to beta and gamma rays in terms of their properties and risks?
Alpha, beta, and gamma rays differ significantly:
- Penetration: Alpha rays are stopped by paper, beta rays by a thin sheet of aluminium, and gamma rays require thick lead or concrete to be blocked.
- Ionisation: Alpha rays have the highest ionising power, followed by beta rays, and then gamma rays with the lowest.
- Risk: Externally, gamma rays are the most dangerous due to high penetration. Internally, alpha rays are the most hazardous because their high ionising power is concentrated in a small area, causing maximum local damage.
7. What is the role of alpha decay in providing power for spacecraft?
Alpha decay is the core process in a Radioisotope Thermoelectric Generator (RTG), which powers deep-space probes like Voyager and Mars rovers like Curiosity. An element like Plutonium-238 undergoes continuous alpha decay, releasing a tremendous amount of heat. This heat is converted directly into electricity by an array of thermocouples, providing a reliable and long-lasting power source where solar panels would be ineffective.
8. Are there any applications of alpha rays in cancer treatment?
Yes, a modern and promising application is Targeted Alpha Therapy (TAT). In this treatment, alpha-emitting isotopes are attached to molecules (like antibodies) that specifically target and bind to cancer cells. Once delivered to the tumour site, the highly energetic but short-range alpha particles destroy the cancer cells with minimal damage to the surrounding healthy tissue, thanks to their high ionising power and very low penetration depth.
