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When you calculate the kinetic energy or the angle of deflection, etc, do you need to take in account relativistic effects (whether you are in the center of mass or in the laboratory system)?

I mean for nuclear reactor physics range (up to 200 MeV).

Maj
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  • A neutron has a (rest) mass of around 940 MeV/c². So you should calculate the $\gamma$ of a neutron with KE of 200 MeV and thence its velocity. As you can see from my graph, the difference between Newtonian & relativistic KE starts becoming significant above 0.1c. – PM 2Ring Jan 17 '21 at 23:26
  • Look at a neutron fission spectrum to see how many neutrons are above 5 MeV in energy . – Jean Jacques Jan 18 '21 at 06:36

1 Answers1

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You could convert MeV to Joules and from there calculate the velocity in m/sec or km/sec. Compare that value to c. If the value you calculate is greater than 0.1c then you should take relativistic effects into account. Use the mass of the neutron in kilograms.

Natsfan
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