Calculation of Residual Dose Around Small Objects Using Mu2e Target as   an Example
  The MARS15 code provides contact residual dose rates for relatively large accelerator and experimental components for predefined irradiation and cooling times. The dose rate at particular distances from the components, some of which can be rather small in size, is calculated in a post Monte-Carlo stage via special algorithms described elsewhere. The approach is further developed and described in this paper. 
V.S. Pronskikh, A.F. Leveling, N.V. Mokhov, I.L. Rakhno (Fermilab), P.   Aarnio (Aalto U.)
physics.acc-ph