MAMA Darks

The dark current of the MAMA detectors varies considerably with time and detector temperature. The dark current in the NUV MAMA is dominated by a phosphorescent glow that results from impurities in the MgF2 faceplate of the detector. The FUV MAMA shows a fainter but less predictable glow, which intensifies as the detector warms up. Two 1380 s dark exposures are taken each week with each MAMA detector to monitor these dark currents, and the results of the these monitoring observations are summarized in the following plots and tables.

After several years in a cold environment, the NUV MAMA shows a high level of dark current. This is expected to decrease over time.