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Dr Mark Marais

May 2025

when particle and antiparticle meet, they annihilate

Particles, Antiparticles & Annihilation

Dr Mark Marais - 2025

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  • explain what a particle and antiparticle is
  • understand and explain particle-antiparticle annihilation
  • explain in the application of PET imaging
  • complete particle-antiparticle annihilation reactions
  • calculate gamma energies in particle-antiparticle annihilation

let’s aim to

Dr Mark Marais - 2025

Dr Mark Marais - 2025

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Dr Mark Marais - 2025

Dr Mark Marais - 2025

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Dr Mark Marais - 2025

Dr Mark Marais - 2025

Bananas, the human body, and other natural sources of potassium-40 release positrons from β+ decay. These positrons react with electrons and release energy from the annihilation, but the reaction poses no health threat. Lightning also produces positrons, which react with matter to generate some gamma radiation. Cosmic rays contain positrons and some antiprotons. PET scans involve positrons. Solar flares may release antiprotons, which become trapped in the Van Allen radiation belt and can cause an aurora. Neutron stars and black holes produce positron-electron plasma.

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Annihilation

If an electron encounters a positron, they annihilate with the transformation of their mass into the energies of two gamma rays.

Annihilate

destroy completely

Physics

convert (a subatomic particle) into radiant energy

Dr Mark Marais - 2025

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In PET Imaging

Dr Mark Marais - 2025

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Radioactive glucose

Dr Mark Marais - 2025

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Gamma pairs

electron

positron

Gamma ray

Gamma ray

Dr Mark Marais - 2025

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Write down the reaction

for…

Dr Mark Marais - 2025

 

 

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Annihilation and Pair Production | vt.physics

Dr Mark Marais

May 2025

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Dr Mark Marais - 2025