Photon/Optical Detectors
type: Concept

XPS
type: Concept
in scheme: instruments
definition: The XUV Photometer System (XPS) measures the solar soft x-ray (XUV) irradiance from 1 to 34 nm and the bright hydrogen emission at 121.6 (H I Lyman-alpha). The solar XUV radiation is mostly emitted from the hot, highly variable corona of the Sun, and these high-energy photons are a primary energy source for heating and ionizing Earth's upper atmosphere. Of all the SORCE instruments, the XPS is most sensitive to flare events on the Sun as the solar XUV radiation often changes by a factor of 2 to 10, or more, during flares. Additional information available at "http://lasp.colorado.edu/sorce/xps_print.html" [Summary provided by Laboratory for Atmospheric and Space Physics]