The two EUV detectors are Crossed Delay Line Detectors (XDLs). The detectors
have 360 pixels in the spatial direction and 1024 pixels in the spectral
direction.
The Ly-
detector has a 
window and a KBr photocathode.
The O VI detector is windowless, but has a protective cover which is to
be removed before launch. Both XDLs
have vacion pumps to maintain vacuum conditions inside the detector during
ground operations.
Each XDL detector has an associated image processor (IP) located in the telescope assembly. The operation of these IPs is described in the next section. Following completion of an exposure, image data is transferred from the IP to either the primary or redundant electronics in the remote electronics unit (REU).
The visible light detector (VLD) consists of a single photomultiplier tube. The device can be used in either a photon-counting mode or a photo-diode mode. Since the amount of visible light data is rather small, generally a number of measurements will be collected in a buffer before the data is telemetered.