In the presence of synchrotron losses, diffusion of an ensembel of relativistic particles in an intraculster medium is investigated. The diffusion coefficient in the medium is found to be constrained by $28.8;{pm};0.4;{leq};Log;D;{leq};30.5;{pm};0.4;cm^2s^{-1}$ with the energy dependency of $D_0{varepsilon}^{mu}$ of ${mu}=0.4{pm}0.2$ as the previous observations suggested. As an important implication of the result, the brightest head-tail radio source NGC 4869, whose radio tail structure is indicative for its orbit within the cluster core, is considered to be the major contributor of particles for the formation of the Coma radio halo.