How were Neutrinos Discovered?

By -

  Table of contents 

HOW WERE 

NEUTRINOS DISCOVERED?


View my previous article here -

View the next article here -

-----------------------------------------

As we discussed earlier, neutrinos are almost invisible, extremely small, almost undetectable particles. Although they are produced in trillions by the sun and travel through our body, it was hard to detect them because they rarely interact with the matter that we are made up of. 

So how were these neutrinos discovered?
  • According to the people who studied how subatomic particles behaved, there was a small particle, emitted every day, that no one had found yet. When it came to equations and paper, there was no getting away from this little particle.
  • People had known it existed since 1931 when Wolfgang Pauli was studying beta decay. During beta decay, an atom emits an electron (or a positron), but Pauli noticed that it emitted this electron in a wide and continuous spectrum of different energy levels. It was almost as if the electron were sharing the total energy with another particle, each carrying a proportion.
  • Three years later, Enrico Fermi confirmed the existence of a particle in his comprehensive theory of radioactive decay. According to Enrico Fermi, this particle could do impressive things. It could, for example, turn a proton into a neutron. When a proton captures a neutrino, it turns into a neutron, and in the process gives off a positron.
  • What it couldn’t do is show up on any instrument at all that measured charge, because it had no charge. It couldn’t show up on an instrument that measured mass because it was almost completely massless.
  • So looking for a neutrino was, at the time, impossible. But Fermi had given the world clues as to how to find the neutrino when he described its power—including its power to turn a proton into a neutron. This was the key that allowed scientists to prove the neutrino existed. The two people who picked up on it were the neutrino researchers Clyde Cowan and Frederick Reines.
  • Unlike a neutrino, a neutron and a positron were both nearly guaranteed to interact with the world sooner or later. The positron would interact sooner. It would hit an electron and annihilate, giving off a gamma ray. The neutron would interact later when it hit the right nucleus at the right time. It would also give off a gamma ray. 
  • The two particles could interact, and give off a gamma ray, at any time, but on average the time between the positron’s flash and the neutron’s flash would be five microseconds. So if they built a detector, put it next to a nuclear reactor which would be giving off neutrons, and got flashes five microseconds apart, they were seeing the evidence of neutrinos.
  • Cowan and Reines built a tank, filled it full of liquid that would send off flashes of light when disturbed, and surrounded the tank with light detectors. The flashes came as predicted, five microseconds apart. 
  • The rest is Nobel history. 😃

-----------------------------------------

View the next article here -


View more structured order of the articles here -

-----------------------------------------

Feel free to ask/share anything additional in the comments section!

I am still learning Particle physics, but will try my best to answer your questions :)

Kindly let me know about any errors here.

You can also share anything additional for this article here.

View my previous article here -

View the next article here -

View more structured order of the articles here -

See more articles here -

Solve brain teasers! View my other blog here-

With Warm Wishes,
Lavanya

Comments

Post a Comment

Popular posts from this blog

What are Quarks, Leptons and Bosons?

By -
    Table of contents  WHAT ARE  QUARKS, LEPTONS  AND  BOSONS? View my previous article here - How were Neutrinos Discovered? View the next article here - The Fundamental Forces ----------------------------------------- Here is a brief overview of what are quarks, leptons and bosons - families of particles that make up the Standard Model! (Based on what has been discussed so far).  * ADDITIONAL * -  A fermion is any particle that has an odd half-integer (like 1/2, 3/2, and so forth) spin.  Quarks  and  leptons , as well as most composite particles, like  protons  and  neutrons , are fermions. QUARKS: Quarks are subatomic particles that are found in protons and neutrons in the atomic nucleus. There are 6 quarks .  Up quark and Down quark belong to the first generation. Charm quark and Strange quark belong to the second generation. Top quark and Bottom quark belong to the third generation. The second and third generation particles are more massive and unstable when compared to the
Read more

Particle Physics - Introduction

By -
Table of contents   PARTICLE PHYSICS - INTRODUCTION View the next article here - More on Particle Physics and Why it matters? ----------------------------------------- What is Particle physics? Let me give a hint by telling you what particles are? Everything in our universe is made up of extremely small components known as particles. Now did you get it? Particle Physics is nothing but the study of how our universe was made and what our universe is constituted of. To prove their existence and see how they behave, scientists observe them until the particles leave a sign. Often, instead of waiting for the particles to leave a sign, they make particles by colliding known particles. How? Well, the accelerators speed up the known particles almost to the speed of light. The particles collide and release massive energy, which results in the creation of new particles. This is why Particle physics is also known as High Energy Physics . At present, there are 17 particles that have been identifie
Read more

Cosmic Rays

By -
Image
    Table of contents  COSMIC RAYS View my previous post here - The Survival of a Neutron View the next article here - (Coming soon!) ----------------------------------------- Cosmic Rays are super fast subatomic particles "raining" down on us from space.  These high-energy particles arriving from outer space are mainly (89%) protons – nuclei of hydrogen, the lightest and most common element in the universe – but they also include nuclei of helium (10%) and heavier nuclei (1%), all the way up to uranium. (Source of information: CERN) Their origin remains to be a mystery.  These are radiations or rather little bits of atoms whizzing by us, even through us, all the time! We cannot feel them, because they don't affect the human body . However, they do show their presence in different ways. For instance, they cause computers to malfunction . Scientists have been studying cosmic rays since the early 1900s. At the beginning of the 20th century, around 1911, a physicist, Vict
Read more