Resonance parameters perturbation with Doppler broadening in Monte Carlo neutron transport problems

In Monte Carlo neutron transport problems, we study the effects of resonance parameters perturbation on collision density using the Taylor expansion methodʹ. The multilevel BreitWigner and Reich-Moore formalisms for only the elastic reaction are used to calculate cross section derivatives at 0 and 300 K. We also calculate collision density derivatives with respect to temperature to evaluate temperature perturbation