Abstract: A mass sensor includes a magnet assembly and a mass analyzer. The mass analyzer includes a ceramic housing formed from two end plates and a center portion. The mass analyzer further includes a thermionic electron emitter ionizer, a double focusing mass spectrometer having superimposed orthogonal magnetic and electric fields, and a microchannel plate ion detector located in the housing cavity. The double focusing mass spectrometer includes an electric sector energy analyzer having a film resistor deposited on an inside surface of each end plate. The film resistors are substantially concentric and congruent and have a circular arc shape. Boundary electrodes are positioned adjacent each curved edge of each film resistor. The mass sensor includes a non-evaporable getter mounted inside the housing cavity and external electrical contacts arranged to form a multi-layer printed circuit card that is installable in a circuit card edge connector.