ANTI MATTER

What is antimatter?

• Matter contains particles (electrons, protons etc).

• Antimatter contains antiparticles (antielectrons, antiprotons etc).

• An antielectron (also called "positron") and an antiproton could form an antihydrogen atom in the same way that an electron and a proton form a normal matter hydrogen atom.

History• The modern theory of

antimatter begins in 1928, with a paper by Paul Dirac.

• Dirac realized his version of the Schrödinger wave equation for electrons was predicting the possibility of antielectrons.

• These antielectrons were discovered by Carl D. Anderson in 1932 and named positrons.

Annihilation

•Annihilation is the process that occurs when a subatomic particle collides with its respective antiparticle.•Ex . Positron + electron = energy

• A Feynman diagram of a positron and an electron annihilating into a photon (gamma rays).

Big bang • During big bang matter and antimatter was

created in equal proportion.• But due to unknown reasons matter overtook

antimatter and what's left is mostly matter!• This is called baryon asymmetry.• This is one among the greatest unsolved

problems in physics.

Storage

• Antimatter cannot be stored in a container made of ordinary matter because antimatter reacts with any matter it touches, annihilating itself and an equal amount of the container.

• Antimatter that is composed of charged particles can be contained by a combination of an electric field and a magnetic field in a device known as a Penning trap.

Penning trap

Uses

• Medical : Antimatter-matter reactions have practical applications in medical imaging, such as positron emission tomography (PET).

POSITRON EMISSION TOMOGRAPHY (PET)

Uses

• Fuel : The reaction of 1 kg of antimatter with 1 kg of matter would produce 1.8×1017 J (180 petajoules) of energy or the rough equivalent of 43 megatons of TNT !!!

Disadvantages

• Cost : To produce 1 gram of antimatter, CERN would need to spend 100 quadrillion dollars and run the antimatter factory for 100 billion years.

• One researcher of the CERN laboratories, which produces antimatter regularly, said:

“ If we could assemble all of the antimatter we've ever made at CERN and annihilate it with matter, we would have enough energy to light a single electric light bulb for a few minutes. “