Answer Happy

Dissociation of alpha particles (Phillips Problem 6.2). The energy needed to dissociate an “He nucleus into two neutrons and two protons is Q = 28.3 MeV. Consider classical and non-relativistic conditions. (a) Derive an expression relating the number densities, statistical factors and quantum concen- trations of 4He nuclei, neutrons and protons coexisting at a temperature T in an equilibrium set up by the reaction 2n+2p. 7 + 4He (b) If the density is p, derive a transcendental equation in terms of Mn, Mp, Mhe, P and Q which can be solved numerically to obtain the temperature for 50% dissociation. [NO need to solve the equation.] Both neutrons and protons are spin-1/2 particles and so have statistical factor 2. Take the statistical factor of 4He nuclei to be 1.