Performance results of the GALEX cross delay line detectors

Abstract

We describe the performance results for the Galaxy Evolution Explorer (GALEX) far ultraviolet (FUV) and near ultraviolet (NUV) detectors. The detectors were delivered to JPL/Caltech starting in the fall of 2000 and have undergone approximately 1000 hours of pre-flight system-level testing to date. The GALEX detectors are sealed tube micro-channel plate (MCP) delay line readout detectors. They have a 65 mm diameter active area, which will be the largest format on orbit. The FUV detector has a spectral bandpass from 115 - 180 nm and the NUV detector has a bandpass from 165 - 300 nm. We report here on the performance of the detectors before and after integration into the instrument. Characteristics measured include the background count rate and distribution, gain vs. applied high voltage, spatial resolution and linearity, flat fields, and quantum efficiency.