Muons Penetrate Ancient Xi'an Fortress Wall | 07 Feb 2023

Why in News?

As per a new study, researchers are examining the fortress wall of Xi’an, an ancient city in China, by using tiny outer space particles Muons that can penetrate hundreds of metres of stone surfaces.

  • Scientists have used a muon detector, called CORMIS (Cosmic Ray Muon Imaging System), to examine the wall of Xi’an city.

What are Muons?

  • About:
    • Muons are subatomic particles raining from space. They are created when the particles in Earth’s atmosphere collide with cosmic rays.
      • Cosmic rays are the clusters of high-energy particles that move through space at almost the speed of light.
    • According to Scientific American magazine, “about 10,000 muons reach every square metre of the Earth’s surface a minute”.
  • Properties:
    • These particles resemble electrons but are 207 times as massive. Therefore, they are sometimes called “fat electrons”.
    • Because muons are so heavy, they can travel through hundreds of metres of rock or other matter before getting absorbed or decayed.
      • In comparison, electrons can penetrate through only a few centimetres.
    • Also, muons are highly unstable and exist for just 2.2 microseconds.

What is Muography?

  • About:
    • The method of scanning large structures owing to the penetration power of muons is called Muography.
  • Applications of Muography:
    • Archaeology:
      • With unique advantages, muography has gained increasing attention from archaeologists as a novel and innovative tool to investigate large-scale archaeological sites.
        • Example: The first use of muography was in the late 1960s when a Nobel Prize-winning physicist named Luis Alvarez teamed up with Egyptologists to look for hidden rooms in the Pyramid of Khafre in Giza.
    • Other Applications:
      • Muography has also found use in customs security, internal imaging of volcanoes and others.

Source: IE