Fig. 6: Dark count trends.
Dark count rate and temperature measurements directly from the two GM-APDs, APD1, and APD2. On the ground before launch, APD1 and APD2 dark count rates at 20 °C were approximately 17 kcps and 26 kcps respectively. a, b Dark counts recorded over one orbit plotted as a function of its temperature during the measurement for 27, 190, 362, 719 orbital days. c All of the dark count rate measurements are adjusted to 10 °C using the exponential fits from (a) and (b). The initial DCR recorded on the ground are subtracted to help capture the radiation induced dark counts (DCRR).
