A Monte Carlo reaction simulation for small-angle correlations between light charged particles

Nuclear reactions often proceed via fusion of projectile and target into a thermalized compound nucleus. For hot compound nuclei of temperature ≈1–5 MeV one expects that a chain of particles (neutrons, protons, alphas…) will be evaporated with a variety of time intervals of ≈10-22-10-20 s. The determination ofthese emission times is a major challenge for nuclear physicists. Such time intervals are too short to measure directly, but they do lead to final-state interactions between charged-particle pairs due to their mutual Coulomb repulsions. Therefore, one expects correlations between the charged-particle pairs that depend on their velocities and separation distances at birth, i.e. the flight distance of the first particle before birth of the second. The KALLIOPI program is a reaction simulation designed to predict the particle-particle correlations as a function of predicted or assumed values of the mean emission times. By comparison of the simulated results to experimental data one can test the basic predictions of decay rates for particle ejection from hot nuclear emitter.