Particle Physics Seminar

With the availability of high energy neutrons in the environment of nuclear energy systems like Accelerator Driven subcritical System (A.D.S.), the probability of occurrence of many non-elastic reaction channels like (n, xn), (n, xnyp), (p, xn), (p, xn) is enhanced. These new reaction channels raise the requirement of fundamental nuclear data in extended high energy regions for a variety of materials which are useful for the development of A.D.S. The (n, xn) and (p, xn) type of reactions which do not have any significant role in conventional thermal and fast reactors except for x = 1 (n, n), or at the most x = 2 i.e. (n, 2n) reaction, have now become important in case of A.D.S., and that is because of the fact that these reactions enhances the neutron multiplication in case of spallation targets like (Pb/Bi). Also, the impact of these reaction channels on the neutronics of the system is quite high. The pronounced possibility of occurrence of new reaction channels like high order (n, xn) reactions in the environment of high energy spallation neutrons has put forward a need to evaluate their contribution and to review their importance w.r.t. to other inelastic reaction channels and also in the candidate materials (target, fuel, and structure) of A.D.S. Having these ideas in mind, the results to be presented will be mainly focused on the following topics: (a) What is the status of cross-section data of (n, xn) like reactions in the present libraries? (b) What is the contribution of (n, xn) reactions w. r. t. to other inelastic channels and fission? (c) Can we use the same definitions of parameters like neutron multiplicity, criticality and energy gain etc. of a conventional reactor for an A.D.S. or is there a need to redefine these parameters? and (d) What are the challenges in measurement of (n, xn) like reaction channels?
The approach followed in this work is theoretical/ phenomenological as well as experimental.