  We report the performance of two prototype TeO2 macrobolometers, operated at
~25 mK, able to identify events due to energy deposited at the detector
surface. This capability is obtained by thermally coupling thin Ge active
layers to the main energy absorber of the bolometer, and is demonstrated by
irradiating the detectors with alpha particles. The temperature variations of
the main absorber and of the active layer are measured independently with doped
Ge thermistors. These results show clearly that an intrinsic limitation of
monolithic low temperature calorimeters, e.g., the impossibility to give
information about event position, can be efficiently overcome using composite
structures.
