What are Muons?

1 min read
Prelims: Science & Technology
What are Muons? Blog Image

Why in news?

  • To analyse 14 kilometres long rampart, researchers deployed a technique called muon tomography or muography, which uses muons to generate three-dimensional images of such large structures.

What are Muons?

  • Muons are subatomic particles raining from space. 
  • The muon was discovered as a constituent of cosmic-ray particle “showers” in 1936 by the American physicists Carl D. Anderson and Seth Neddermeyer.
  • They are created when the particles in Earth’s atmosphere collide with cosmic rays — clusters of high-energy particles that move through space at just below the speed of light.
  • It has two forms, the negatively charged muon and its positively charged antiparticle.
  • These particles resemble electrons but are 207 times as massive. Therefore, they are sometimes called “fat electrons”. 
  • Muons are so heavy, they can travel through hundreds of metres of rock or other matter before getting absorbed or decaying into electrons and neutrinos
  • They are highly unstable and exist for just 2.2 microseconds.

What is muon tomography?

  • Although muon tomography was first used in the 1960s, it has only recently gained widespread use among researchers, particularly in archaeology.
  •  It is conceptually similar to X-ray but capable of scanning much larger and wider structures, owing to the penetration power of muons.
  • All that is required is to place a muon detector underneath, within, or near the object of interest.
  • The detector then tracks the number of muons going through the object from different directions, to form a three-dimensional image.
  • The image is then compared with a muon image of the “free sky.” This indicates how many muons have been blocked. The final picture is essentially a shadow of the object, in the light of cosmic muons.”


Q1) What is an electron?

An electron is a stable subatomic particle with a negative electrical charge.

Source: Scientists use outer space particles to examine the fortress wall of Xi’an city: What are muons and how are they used to analyse large structures?