MonChER: Monte-Carlo generator for CHarge Exchange Reactions. Version   1.1. Physics and Manual
  MonChER is a Monte Carlo event generator for simulation of single and double charge exchange reactions in proton-proton collisions at energies from 0.9 to 14 TeV. Such reactions, $pp\to n+X$ and $pp\to n+X+n$, are characterized by leading neutron production. They are dominated by $\pi^+$ exchange and could provide us with more information about total and elastic $\pi^+ p$ and $\pi^+\pi^+$ cross sections and parton distributions in pions in the still unexplored kinematical region. 
R.A. Ryutin, A.E. Sobol, V.A. Petrov
hep-ph hep-ex