Three-dimensional simulation of electron-acoustic detections

Abstract

In electron-acoustic ͑EA͒ detection, a periodically modulated electron beam is impinging on a sample to excite thermo-acoustic signals, and a PZT transducer bonded on the back surface of the sample is used to detect the thermo-acoustic signals. Based on the conditions of the EA detection experiment, theoretical analyses of 3-D temperature distributions in the sample, 3-D elastic fields in the sample and piezoelectric transducer, and piezoelectric output signals of the transducer are given. Generally, the vibration modes and the electrical output signals of the transducer are hard to calculate because of the complicated structures, i.e., complicated boundary conditions, thus a finite element method ͑FEM͒ is used to simulate the electron-acoustic signals. According to the corresponding FEM model, the frequency spectra of the detected EA signals can be calculated. Meanwhile, the related experimental measurements for several homogeneous samples are carried out. Comparing the theoretical simulated results with those of the experiments, it shows that both are in good agreement with each other. Finally, using this FEM model, the dependences of the electron-acoustic signals on the thermal and elastic properties of several samples are investigated.