The thermal conduction and Navier- Stokes equations are used to obtain the stress field generated by a chopped electron beam incident on a disk sample. The piezoelectric equation is then used to obtain the output sign...The thermal conduction and Navier- Stokes equations are used to obtain the stress field generated by a chopped 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 the signal generation mechanism and spatial resolution in scanning electron acoustic microscopy ( SEAM). It is shown that a time- variant heat source generated both a thermal wave and an acoustic wave simultaneously, and thermal- to- acoustic wave mode conversion oc-cured on the boundary surfaces depends on the amplitudes and the gradients at boundary surfaces of both heat source and thermal waves. It is argued that the spatial resolution of a imaging system operated in the near field, such as SEAM and thermal wave microscope, is dependent on the distance between the heat source and scatterer and, at best, the lateral resolution in SEAM is of the order of the diameter of the focal spot of the electron beam.展开更多
文摘The thermal conduction and Navier- Stokes equations are used to obtain the stress field generated by a chopped 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 the signal generation mechanism and spatial resolution in scanning electron acoustic microscopy ( SEAM). It is shown that a time- variant heat source generated both a thermal wave and an acoustic wave simultaneously, and thermal- to- acoustic wave mode conversion oc-cured on the boundary surfaces depends on the amplitudes and the gradients at boundary surfaces of both heat source and thermal waves. It is argued that the spatial resolution of a imaging system operated in the near field, such as SEAM and thermal wave microscope, is dependent on the distance between the heat source and scatterer and, at best, the lateral resolution in SEAM is of the order of the diameter of the focal spot of the electron beam.
