Positron Annihilation

Most recent answer: 05/14/2017

You must have heard about positron emission which happens in some radioactive substances. But why don't these released positron don't annihilates with electron as we have seen such decays but never heard of any annihilation explosion caused by the substance.
- Raghav (age 14)

Yes, positron emission is quite familiar. It's often used in medical tests, under the name Positron Emission Tomography (PET scan). The positrons do end up annihilating with electrons. The energy released in each annihilation is small because the masses are small.

Mike W.

(published on 05/14/2017)