  We show that a two-level atom resonantly coupled to one of the modes of a
cavity field can be used as a sensitive tool to measure the proper acceleration
of a combined atom-cavity system. To achieve it we investigate the relation
between the transition probability of a two-level atom placed within an ideal
cavity and study how it is affected by the acceleration of the whole. We
indicate how to choose the position of the atom as well as its characteristic
frequency in order to maximize the sensitivity to acceleration.
