# High Energy Electron

## Main Question or Discussion Point

greetings..

i have 1 question:
When a very high energy electron hits a target material, four particles emerge from the target, that is three electrons and a positron, instead of just two electrons, the incident and ejected electrons. It seems that the two extra particles are created out of nothing. Do you agree with this statement?

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Nugatory
Mentor
greetings..
When a very high energy electron hits a target material, four particles emerge from the target, that is three electrons and a positron, instead of just two electrons, the incident and ejected electrons. It seems that the two extra particles are created out of nothing. Do you agree with this statement?
No. They are created, via Einstein's famous $E=mc^2$, from the energy of the incoming electron.

Dale
Mentor
i have 1 question:
When a very high energy electron hits a target material, four particles emerge from the target, that is three electrons and a positron, instead of just two electrons, the incident and ejected electrons. It seems that the two extra particles are created out of nothing. Do you agree with this statement?
I would say 5 particles emerge. 3 electrons, a positron, and a cation. The cation is important because it is required for conservation of charge. The net charge before the collision is -1 and the net charge afterwards is also -1. All other quantities are also conserved.