ocr: CELIAS INSTRUMENT The CELIAS instrument consists of three different sensors with associated electronics, which are optimized each for a particular aspect of ion composition. These aspects are the elemental, isotopic, and ionic charge composition of solar wind or energefic ions emanating from the Sun. In addition, the Solar EUV Monitor (SEM) has been included into CELIAS for monitoring the absolute EUV flux from the Sun. Sensors: MTOF (Mass lime-ot-Flight sensor) possesses unprecedented mass resolution for solar-wind composition studies. The MTOF sensor is a high resolution retarding potential ...