ASA 124th Meeting New Orleans 1992 October

3aEAb2. Electron tunneling sensors.

T. W. Kenny

W. J. Kaiser

H. K. Rockstad

J. K. Reynolds

Ctr. for Space Microelectron. Technol., Jet Propulsion Lab., Pasadena, CA 91101

Many physical sensors operate by coupling the signal of interest to deflection of a sensor component, and utilizing a displacement transducer to produce an electrical signal. The development of miniature high-performance sensors have been limited by the availability of small, sensitive transducers. A novel accelerometer has been designed that utilizes an electron tunneling transducer to detect the relative motion of a suspended proof mass. The sensitivity of the tunneling transducer allows miniaturization of the device with resolution near 10[sup -8] g/[radical Hz] from 10 Hz to 1 kHz. Thermal noise in the positions of sensor components is important for high-resolution miniature accelerometers, and is the dominant factor in selection of design parameters. Thermal noise for this dual element system will be discussed and compared with other noise sources. A simple closed-loop electronic feedback system that is used with these sensors will also be described. Preliminary test results will be described. This system offers improved resolution, compact geometry, low mass, and low cost relative to present miniature accelerometers or acoustic sensors. A wide range of possible applications exist including underwater acoustics. [Work supported by NAWC, and SDIO/IST.]