Absolute detection efficiency of space-based ion mass spectrometers and neutral atom imagers

Space-based ion mass spectrometers and neutral atom imagers often utilize a thin foil for generation of secondary electrons and employ a coincidence measurement between detection of the secondary electrons and detection of the primary ion or neutral atom, allowing unambiguous detection of the particle in a large noise background and determination of properties of the particle using time-of-flight measurement. We demonstrate a simple and straightforward method for laboratory calibration and in situ quantification and monitoring of the absolute detection probabilities of the detectors and the absolute detection efficiency of the detector subsystem without knowledge of the incident particle flux.