Key elements of a low voltage, ultracompact plasma spectrometer

Taking advantage of technological developments in wafer-scale processing over the past two decades, such as deep etching, 3-D chip stacking, and double-sided lithography, we have designed and fabricated the key elements of an ultracompact (1.5 cm)³ plasma spectrometer that requires only low-voltage power supplies, has no microchannel plates, and has a high aperture area to instrument volume ratio. The initial design of the instrument targets the measurement of charged particles in the 3-20 keV range with a highly directional field of view and a 100% duty cycle; i.e., the entire energy range is continuously measured. In addition to reducing mass, size, and voltage requirements, the new design will affect the manufacturing process of plasma spectrometers, enabling large quantities of identical instruments to be manufactured at low individual unit cost. Such a plasma spectrometer is ideal for heliophysics plasma investigations, particularly for small satellite and multispacecraft missions. Two key elements of the instrument have been fabricated: the collimator and the energy analyzer. An initial collimator transparency of 20% with 3° × 3° angular resolution was achieved. The targeted 40% collimator transparency appears readily achievable. The targeted energy analyzer scaling factor of 1875 was achieved; i.e., 20 keV electrons were selected for only a 10.7 V bias voltage in the energy analyzer.