Radioactivity Gamma Decay


The gamma decay is a kind of radioactivity in which unsteady atomic nuclei gives out excess energy by a spontaneous electromagnetic process. The most notable form of gamma decay is gamma emission, gamma rays flows in the form of photons, and packets of electromagnetic energy of very short wavelength. Gama-decay also includes two key electromagnetic processes, internal pair production and internal conversion.

In internal conversion excess energy present in the nucleus is directly transferred to one of its orbiting electrons and in the case of internal pair production excess amount of energy is converted in the particular electromagnetic field of a nucleus into an electron and positron which are emitted together.

What is gamma decay?

Gamma Decay process displays emission of electromagnetic radiation associated with extremely high frequency hence it generates very high energy. It gives out the excess amount of energy that is necessary to stabilize the unstable nucleus. The nucleus drops from high energy to a lower energy level by emitting high energy photons by the process of gamma decay. This energy level transition is in the line of MeV.

Hence, similar to the x-rays the gamma rays emitted also displays very high energy of the order. The gamma rays come to form the nucleus and due to the presence of the high amount of energy they are extremely penetrating and hence these rays are dangerous to the life forms on the planet.

Unlike alpha decay and beta decay the parent nucleus does not go through a physical change. Throughout the radioactivity gamma decay the daughter nuclei and the parent nuclei are identical. Mostly, the gamma decay occurs after the radioactive nuclei have gone through the stages of alpha decay and beta decay. The alpha and beta decay leaves the daughter nuclei in an excited state. The daughter nuclei from the excited state returns to the ground state by the emission of more than one high energy gamma rays.

Figure 1: Gamma decay

Gamma-ray: sources

The sources of gamma rays other than the radioactive decay include different natural phenomena. According to Mailyanet al. (2020),themost prominent examples are terrestrial thunderstorms and lightning. As opined by De Angelis &Mallamaci (2018), the gamma rays burst out in space from various celestial bodies including pulsars, quasars and galaxies.

From these celestial bodies, the gamma rays spread out in space. The collapse of a star, results in the formation of a black hole which is known as a hypernova. This event of hypernova results in the burst of long duration gamma rays emissions (NASA, 2022).

These bursts of emissions produce a total energy output of around 1044 Joules which is equivalent to the total amount of energy the Sun will produce in its entire lifetime. The span of the bursts lasts between 20 to 40 seconds.

Figure 2: gamma ray sources

Gamma rays applications

Most of the high energy events in the Universe happens through the radiation of gamma rays.

These events however cannot be witnessed without the gamma-ray detectors. In order to note this concerning issue, scientists have created a big satellite called the Fermi Gamma-ray Space Telescope that helps in providing a clear view of the events occurring in the discovered universe.

  • The gamma-ray sensors are used in the process of food packaging and the chemical industry. This is so done to measure the density, thickness and composition. As opined by Roshaniet al. (2021),
  • gamma radiation is also used in petroleum industry.
  • Gamma Rays are also used in medical practices. Gamma rays are used in the field of oncology, it is usedin the treatment of certain types of cancers(studiousguy,2022). In this treatment procedure high energy gamma beams are irradiated to the cancer cells in order to kill them.
  • Gamma rays are used in civil engineering, it is used to check the change in density and the weak points found in the oil line.
  • According to Caraveo (2020), Gamma rays are used in the field of astronomy, it used to view distant objects in the universe. Gamma rays are also used to kill various small insects including moulds, bacteria and poisonous bacteria.

Figure 3: application of Gamma ray


The radioactivity processes are generally governed by three key processes, alpha decay, beta decay and gamma decay. In the gamma decay process, high energy photons are emitted. The gamma rays are mostly found in the abundance in the space due to the celestial activities. However, there are various real-life applications. Gamma rays imparts high damage on the cellular level of the organisms. Due to the penetrating nature of the gamma rays, they pass through the entire body of the creatures. However gamma rays are a lot less ionizing compares to the alpha rays or beta rays. Therefore, the severity is lesser compared to the penetration


Q1. What are some of the applications of gamma-ray sensors?

The gamma-ray sensors are used in the food-packaging process. The gamma-ray sensors are used in the chemical industry to measure various aspects of thickness, density and composition of the chemicals. Gamma rays are also used to treat certain types of cancers. It is also used in the disinfectant industries.

Q2. What are the three different kinds of radioactive decays?

There are three key types of radioactive decays. Alpha decayis the process that leads to the emission of helium nucleus. Beta Decay that causes the release of electrons and gamma decay, ithelps in liberation of high energy photons

Q3. What is meant by gamma decay?

Gamma decay is associated with the process that helps in the generation of electromagnetic radiation that belongs to very high frequency. The high frequency is attributed to the release of high energy that gives out excess energy that is required to stabilize the unstable nucleus.

Q4. Who discovered the Gamma radiation?

Gamma rays were discovered by a French chemist and physicist, Paul Villard. He discovered gamma rays in the year 1900.

Q5. What are the traits of Gamma rays?

Gamma rays have a very short wavelength and have the highest amount of energy among all radiation.



Caraveo, P. A. (2020). The golden age of high-energy gamma-ray astronomy: the Cherenkov Telescope Array in the multimessenger era. La Rivista Del NuovoCimento, 43(6), 281-318. Retrieved from:

De Angelis, A., &Mallamaci, M. (2018). Gamma-ray astrophysics. The European Physical Journal Plus, 133(8), 1-18. Retrieved from:

Mailyan, B. G., Nag, A., Dwyer, J. R., Said, R. K., Briggs, M. S., Roberts, O. J., ... &Rassoul, H. K. (2020). Gamma-ray and radio-frequency radiation from thunderstorms observed from space and ground. Scientific Reports, 10(1), 1-9.Retrieved from:

Roshani, M., Phan, G., Faraj, R. H., Phan, N. H., Roshani, G. H., Nazemi, B., ... &Nazemi, E. (2021). Proposing a gamma radiation based intelligent system for simultaneous analyzing and detecting type and amount of petroleum by-products. Nuclear Engineering and Technology, 53(4), 1277-1283. Retrieved from:


NASA, 2022.About gamma rays. Retrieved from: [Retrieved on: June 10, 2022]

Studiousguy,2022.About gamma ray examples. Retrieved from: [ Retrieved on : June 10, 2022]


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