Through the application of a new approach to energy analysis to microelectromechanical systems, the flat plasma spectrometer (FlaPS) provides a solution to the investigation of plasma distributions in space. It is capable of measuring the kinetic energy and angular distributions of ions in the space environment for energies ranging from a few eV to 50 keV. A single pixel of a FlaPS instrument has been designed, built, and tested to occupy a volume of 1 cm3, and is characterized by a high throughput-to-volume ratio, making it an ideal component for small-scale satellites. The focus of this work is on the design, fabrication, simulation, and testing of the instrument front end that consists of a collimator, parallel plate energy analyzer, and energy selector mask. Advanced microfabrication techniques enable fabrication of the miniature plasma spectrometer with geometric factor 4.9×10-5 cm2-sr per pixel and an entrance aperture area of 0.01 cm2. Arrays of narrow collimator channels with 4-deg angular divergence and high transmission allow energy analysis of ions without the need for focusing, the key feature that enables large mass reduction. It is also shown that the large plate factors achievable with this approach to energy analysis offer definite advantages in reducing the need for excessively high voltages.
The function of a large number of MEMS and NEMS devices relies critically on the transduction method employed to convert the mechanical displacement into electrical signal. Optical transduction techniques have distinct advantages over more traditional capacitive and piezoelectric transduction methods. Optical interferometers can
provide a much higher sensitivity, about 3 orders of magnitude, but are hardly compatible with standard MEMS and microelectronics processing. In this paper, we present a scalable architecture based in silicon on sapphire (SOS) CMOS 1 for building an interferometric optical detection system. This new detection system is currently
being applied to the sense the motion of a resonating MEMS device, but can be used to detect the motion of any object to which the system is packaged. In the current hybrid approach the SOS CMOS device is packaged with both vertical cavity surface emitting lasers (VCSELs) and MEMS devices. The optical transparency of the sapphire substrate together with the ultra thin silicon PIN photodiodes available in this SOS process allows for the design of both a Michelson type and Fabry Perot type interferometer. The detectors, signal processing electronics and VCSEL drivers are built on the SOS CMOS for a complete system. We present experimental data demonstrating interferometric detection of a vibrating device.
Through the application of a new approach to energy analysis to microelectromechanical systems (MEMS), the Flat Plasma Spectrometer (FlaPS) presented here provides a solution to the investigation of plasma distributions in space. It is capable of measuring the kinetic energy and angular distributions of ions/electrons in the space environment for energies ranging from a few eV to 50keV. A single pixel of a FlaPS instrument has been designed, built and tested to occupy a volume of approximately one cubic centimeter, and is characterized by a high throughput-to-volume ratio, making it an ideal component for small-scale satellites. The focus of this paper is on the design, fabrication, simulation, and testing of the instrument front end that consists of a collimator, parallel plate energy analyzer, and energy selector mask. Advanced micro-fabrication techniques enable fabrication of the miniature plasma spectrometer with geometric factor 4.9x10-5 cm2-sr per pixel and an entrance aperture area of 0.01cm2. Arrays of narrow collimator channels with 4° angular divergence and high transmission allow energy analysis of ions/electrons without the need for focusing, the key feature that enables large mass reduction. It is also shown that the large plate factors achievable with this approach to energy analysis offers definite advantages in reducing the need for excessively high voltages.
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