The Dark Current and Hot Pixel Percentage of James Webb Space Telescope 5 μm Cutoff HgCdTe Detector Arrays as Functions of Temperature

Abstract

We measured the median dark current and "hot pixel" percentage of $λ${\~{ }}5 $μ$m cutoff HgCdTe James Webb Space Telescope (JWST) Near Infrared Spectrograph HAWAII-2RG (H2RG) detector arrays as functions of temperature. Although these measurements were made in the context of JWST, we believe that they will interest others using H2RGs. We found that the median dark current depended only weakly on temperature throughout the 36.5 K$\le$T$\le$45 K temperature range (although there were some exceptions). In contrast, the hot pixel percentage depended strongly on temperature, with the percentage of hot pixels approximately doubling for each 6 K temperature increase. Moreover, the data suggest that this trend becomes stronger at warmer temperatures. These new measurements broadly confirm our previous finding that T{\~{ }}38 K is close to optimal for current-generation $λ${\~{ }}5 $μ$m cutoff H2RGs, although somewhat warmer (T$\le$45 K) temperatures may be used if lower pixel operability is acceptable.