question_answer 53)

  Deuteron is a bound state of a neutron and a proton with a binding energy B = 2.2 M. A -ray of energy E is aimed at a deuteron nucleus to try to break it into a (neutron + proton) such that the n and p move in the direction of the Incident -ray. If E=B, show that this can not happen. Hence, calculate how much bigger than B must E be for such a process to happen.

Answer:

                  Applying principle of conservation of energy in the given situation,                         ?(i) From the principle of conservation of linear momentum,                                ?(ii) If E=B, eqn. (i) would give p n= pp =0. Hence, the process cannot take place. For the process to take place, let                 From (i),                               using (ii),  or For pp to be real, the determinant on RHS must be positive.             or Hence, E must be bigger than B by =B2/4mc2, for the given process to happen.