Dresden 2003 – wissenschaftliches Programm
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DS: Dünne Schichten
DS 24: Poster
DS 24.9: Poster
Dienstag, 25. März 2003, 14:30–17:00, P2a
Investigation of the ion acoustic effect in solids using high energy pulsed ion beam — •Chavkat Akhmadaliev and Lothar Bischoff — Forschungszentrum Rossendorf e.V., Bautzner Landstraße 128 (B6), 01328 Dresden
The interaction of a pulsed ion beam with solids leads to a small temperature variation in the near subsurface region. Due to the local heating of the target and the momentum transfer elastic waves are generated. The measurement of the waves gives new information about the internal structure and properties of the sample. Experiments were made using O+, O2+, O3+, O4+, Si2+, Si3+, Si4+, Au2+, Au3+ ions providing by a 3MeV-Tandetron accelerator. To form the needed very short pulses a high voltage switch based on a HV valve was designed allowing shortest pulse duration of about 500 ns. The energy was varied in the range from 1.5 to 12 MeV. The acoustic signal was detected on the back side of Al, Fe, Cu and Si samples using different piezoelectric transducers with a high frequency preamplifier. The amplitude as a function of pulse duration, energy, spot size and wave directivity was measured. The linear dependence of the amplitude on the energy underlines that the main mechanism of the elastic wave generation in solids is the thermal effect. No any dependence on the ions type or their charge state was found. The contribution of the momentum transfer from the projectile ions to the target atoms in this energy range is negligible.