F - Neutron Decay

Question 1

How was the neutron discovered?

Answer 1

Discovered by James Chadwick in 1932

Alpha particles bombarded beryllium—> Neutrons were then given off which bombarded paraffin wax —> Proton were given off which were then detected

Question 2

Thermal neutrons; energy state, velocity,

Answer 2

Thermal neutrons - 0.025eV
Fast neutrons - 1-20MeV

Neutrons lose energy until they reach thermal equilibrium - thermal neutron is at room temp - neutron energies have a Maxwellian distribution about the mean

Key result:

Both a neutrons energy and velocity are dependent on temperature

Question 3

How to find the velocities and energies of thermal neutrons? What are they?

Answer 3

Set the derivatives to zero and solve

Most probable velocity, vp = SQRT(2kT/m)
Most probable energy, Ep = 1/2 KT

Energy relating to most likely velocity = kT

@ 20c, E = kT ~ 0.025eV and velocity ~ 2197m/s