Comparison of Monte Carlo methods for adjoint neutron transport

Solving the adjoint linear transport equation by Monte Carlo methods can be convenient for applications emerging in radiation shielding, where the detector is typically small (in terms of probability of detecting a signal). In this work we compare a few stochastic models that can be used in order to formally solve the adjoint transport equation by simulating artificial particles called adjunctons: these models differ in the form of adjuncton cross-sections, scattering laws and multiplicities. In view of testing the accuracy and the performances of these schemes, we have selected some benchmark configurations for continuous-energy transport in infinite media, where reference solutions can be established. The role of population control techniques, such as Russian roulette and splitting, is also carefully examined.