Elevation response of FM SWA-EAS sensors heads (SWA-EAS1 in left column, SWA-EAS2 in right column). Top row: counts received in each sensor elevation bin as a function of the elevation angle of the incident electron beam. Second row: elevation angle showing peak response as a function of the voltage ratio applied to the deflectors, showing good linearity. Bottom row: FWHM of the response angle as a function of the voltage ratio, indicating that there is an asymmetry in the response for “upward” and “downward” sweeps and that the acceptance angle is larger at larger deflections.