The FUSE detectors: on-orbit use and lessons learned
Future EUV/UV and Visible Space Astrophysics Missions and Instrumentation
The FUSE (Far Ultraviolet Spectroscopic Explorer) instrument includes two large-format microchannel plate detectors with double delay line anodes. The generally good detector performance has permitted the collection of scientific data with high spectral resolving power, and has enabled the observation of fainter objects than could be easily observed with previous missions in this wavelength range. As with any complex instrumentation, however, there have been numerous challenges which have
... es which have arisen during the mission. We discuss the on-orbit performance of the FUSE detectors since launch, and describe some of the lessons learned. This includes a discussion of their operation on orbit and the effects that detector performance has had on the scientific data collected. The strategies taken to minimize the impact of detector anomalies on the data will also be discussed. The two FUSE detectors are identical microchannel plate (MCP) detectors with double delay line anodes. The active area of each is divided into two segments, each with its own MCP z-stack, anode, and associated electronics. The < 10 mm gap between the two segments allows each to be operated independently without affecting the other. The details of the design of the FUSE detector hardware has been presented earlier, and will not be repeated here. However, it is worth noting that the detector is 5,6 by nature an analog device, with no fixed pixels. The pixel values reported by the electronics are the results of an analog-todigital conversion of the calculated photon position; this fact has important implications for many of the effects discussed below.