SCANNING TUNNELING MICROSCOPE COMBINED WITH A SCANNING ELECTRON-MICROSCOPE (original) (raw)
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Active Vibration Isolation for a Long Range Scanning Tunneling Microscope
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Vibration isolation or control is critical for the optimum operation of the Molecular Measuring Machine (M 3), a high-resolution, length-metrology instrument at the National Institute of Standards and Technology. This paper describes the extension of the M3 Mallock isolation suspension from passive to six degrees-of-freedom (DOF) active vibration isolation. System modeling is presented, and experimental system identification is carried out for the purpose of model verification. The paper then compares the vibration isolation performance achieved using a classical proportional-integral-derivative (PID) controller versus that achieved using a modified, model-based, Linear-Quadratic-Gaussian (LQG) controller. Attenuation of 3 dB to 15 dB is achieved within the active vibration isolation control bandwidth, and images taken with the M 3 scanning tunneling microscope (STM) probe show improved performance.
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Review of Scientific Instruments, 1990
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