1. Mar 8, 2007

disregardthat

What velocity does the electron that is emitted from a beta-decay have? And what velocity does the Alpha particle have when it's emitted?

2. Mar 8, 2007

beta decay:The spectrum is continuous I think, It depends on the distribution of P, over the neutrino , electron , and the Nucleus.
But the energy is usually from several 100 Kev to Mev's

3. Mar 8, 2007

Meir Achuz

The beta decay spectrum is continuous. The electron has a maximum velocity determined by energy conservation. For neutron decay, the maximum electron energy is approximately given by E=M_n-M_p. Then v=p/E with p=\sqrt{E^2-m_e^2}~1-m_2^2/2E, which is close to but a bit
smaller than 1. (all in units with c=1)
For nuclear beta decay, put in the masses of the nuclei.

The alpha particle has a definite velocity. Its energy is the difference in masses of the initial and final nuclei. Then v is found as above, but a nonrelativistic approximation is usually good.

4. Mar 10, 2007

disregardthat

Hmm, I don't know how to use that equation since I know very little of particle physics. How would you approximate a normal velocity for an electron to be when it's released for example from an uranium-238?

5. Mar 10, 2007

Astronuc

Staff Emeritus