  Applications of Unruh-Fulling (UF) effect are well studied in literature via
the interaction of Unruh-DeWitt (UD) detector and {\it single} scalar field. In
this work, we investigate a toy model, where the detector is interacting {\it
simultaneously} with the {\it multiple} scalar fields. Our study reveals that
the transition rate of the system significantly depends on the acceleration of
the detector and the number of scalar fields ($n$). For $n\gg1$, there exists a
{\it critical acceleration}, beyond which the transition rate becomes
drastically high than the accelerations below the critical point. The
appearance of such critical point never occurs in case of the interaction of UD
detector and {\it single} scalar field.
