Update on the Development of the Collision Meter

The collision meter will enable precise in-situ measurements of the major neutral gas species in the upper atmosphere (95-200 km). The principle of operation can be summarized as: A beam of charged particles is emitted from from the instrument, perpendicular to the ambient magnetic field. By gyromotion the beam returns to the instrument. From the amplitude of the collected beam, information can be extracted about the neutral density and composition, and about the nature of collisions between charged and neutral species in the upper atmosphere. The current technology readiness level (TRL) of the collision meter is 1, which means that paper study shows the possibility for a useful scientific instrument. We have begun a project which will ultimately advance to TRL 5. The present work reports on work to bring the TRL to 3. We present an update on the development of the collision meter in the laboratory. Using a magnetic field defined by a 3-axis Helmholtz coil, we have tested an initial prototype of the instrument in a controlled environment. By varying the ambient gas mixture and the characteristics of the emitted beam, we have made a preliminary investigation into the response of the instrument. We discuss the implications of this study for the continuing development of the collision meter.