Signal generation and spatial resolution in scanning electron acoustic microscopy
-
-
Abstract
The thermal conduction and Navier-Stokes equations are used to obtain the stress field generated by an electron beam incident on a disk sample. The piezoelectric equation is then used to obtain the output signal of the transducer coupled to the sample. The results lead to a consideration of a signal generation mechanism and the spatial resolution in scanning electron acoustic microscopy (SEAM). It is shown that both thermal and acoustic waves are generated by time-variable heat source simultaneously and the thermal-to-acoustic mode conversion is dependent on the magnitudes of the thermal wave and the driving source and their gradients at boundary surfaces. It is argued that in the near-field the spatial resolution is dependent on the distance beteween the driving source and scatterer and, at best, the lateral resolution is of the order of the diameter of the focal electron beam. Comparisons with experimental findings in SEAM are presented.
-
-