Difference Between Alpha, Beta and Gamma Particles

Alpha, Beta and Gamma are the three types of particles which are the results of radioactive decay. The crucial difference between alpha, beta and gamma particles lies in their charge constituent. Alpha is a positively charged particle, beta is negatively or positively charged. On the contrary, gamma particle has no charge and so is neutral.

Basically, radioactive decay is a process in which an unstable atomic nuclei releases energy in order to get stabilized.  And this release of energy takes place in the form of alpha, beta and gamma rays.

With the emission of these particles, the nucleus is transformed to a lower energy state and the decaying continues till the time the nucleus gets stabilized.

So, the particles whose emission stabilizes an unstable nucleus are alpha, beta and gamma. These three are differentiated on the basis of the behaviour possessed by them and the penetration power.

Radioactivity was discovered by Henry Becquerel in the year 1896. Further, it was discovered by Rutherford between 1900 to 1903 that alpha, beta and gamma are the radioactive substances that are emitted as the result of radioactivity.

Here we will discuss the various differences between the three. But before that have a look at the contents we are going to discuss in this article.

Content: Alpha Vs Beta Vs Gamma Particles

  1. Comparison Chart
  2. Definition
  3. Key Differences
  4. Conclusion

Comparison Chart

Basis for ComparisonAlphaBetaGamma
BasicIt is identical to helium nucleus due to presence of protons.It is an electron or a positron.It is a photon that carries electromagnetic energy.
ChargePositively chargedPositively or negatively chargedNo charge
Propagating speedVery less than velocity of light.Little less than the velocity of light.Equal to the velocity of light.
Mass6.65*10-27 Kg9.10*10-31 Kg0
SizeQuite LargeComparatively small
Extremely minute as it is massless.
Penetrating abilityLowModerateHigh
Ionizing powerMoreLessVery less
Effect of magnetic and electric fieldShows deflectionShows deflectionNo deflection
RangeApprox. 10 cm in airUp to certain mSeveral m in air
Effect of emission from the nucleusVaries chemical composition of the elementChanges the chemical composition of the elementNo change in chemical composition of the element
ApplicationIn unsealed source radiotherapy.In monitoring thickness of material.In nuclear industry.

Definition of Alpha Particle

Alpha particle is also known as alpha rays. An alpha particle consists of 2 protons and 2 neutrons bounded together similar to a helium nucleus. So, alpha decay results in an alpha particle.

Alpha particles generally possess kinetic energy of 5 MeV and have velocity around 5% of the velocity of light.

As it has 2 protons and there is no electron present to balance the two positive charges thus in total the charge on the single alpha particle is +2.

Definition of Beta Particle

These are also called beta rays and are unit negatively or positively charged particles emitted during beta decay.

Beta particles have a kinetic energy of about 0.5 MeV and propagate approximately with the speed of light.

An unstable atom which is rich in neutron produces beta particles. In this, basically, the unstable atom gets stabilized by removing the neutrons and transforming them into electrons or positrons.

Definition of Gamma Particle

Gamma particles are also known as gamma rays and are chargeless. These are high energy photons that carry electromagnetic waves.

As these possess no properties of a charged substance thus remains unaffected from the electric and magnetic field. And thus, there occurs no chemical element variation when a gamma particle is emitted.

The energy of gamma rays lies between few KeV to around 8 MeV and sometimes extremely high energy gamma rays have 100 to 1000 TeV range.

Key Differences Between Alpha, Beta, Gamma Particles

  1. An alpha particle is a positively charged particle consisting of 2 protons and 2 neutrons. Whereas a beta particle is a charged particle consisting of either unit negative or positive charge. As against, a gamma particle has no charge constituent and is of neutral nature.
  2. When an alpha particle is emitted by a nucleus then the release of positive charge changes the chemical composition of the element. Similarly, when a beta particle is emitted then the release of either electron or positron changes the chemical element. While when a gamma particle is emitted, then there is no change in the chemical element.
  3. Gamma particles have the highest penetrating ability in comparison to the other two. Whereas alpha particles have the lowest penetrating ability and can be stopped by a sheet of paper. On the contrary, beta particles have a moderate penetrating ability which is generally 100 times more than the alpha particle.
  4. The velocity of propagation of alpha particle is least in comparison to beta and gamma. Basically, the velocity of beta particles is approximately equal to the velocity of light and gamma particles move with the velocity of light.
  5. The mass of an alpha particle is more than a beta particle, as the mass of the beta particle is 1/1000 to that of the proton. While gamma particle is massless.
  6. In the presence of the electric and magnetic field, alpha and beta particles are deflected towards negative and positive plates respectively. But gamma particles show no such deflection.
  7. When emission occurs then alpha particles generally travel up to a range of certain centimetres only. While the highest propagation range is offered by the gamma particles as against beta can travel a significantly moderate distance in meters.
  8. The highest mass of the alpha particle than beta and gamma accounts it for the highest ionization power. However, as the neutron is massless thus has the least ionization power and beta particle possesses moderate ionization power.


So, the above discussion concludes that according to the property possessed alpha, beta and gamma particles are differentiated. Alpha particles are used in radiotherapy during the treatment of cancer as it has low penetration ability thus the chances of damage of healthy cells are least.

While beta particles are used to check for the thickness of the material and gamma particles are used in the nuclear industry.

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