Blooming in H2RG arrays: Laboratory measurements of a second brighter-fatter type effect in HgCdTe infrared detectors

Abstract

Improved measurement and calibration of detector behaviors will be crucial for future space missions, particularly those aiming to tackle outstanding questions in cosmology and exoplanet research. Similarly, many small detector effects, such as the nearest-neighbor interactions of the brighter-fatter effect and interpixel capacitance, will need to be considered to ensure measured signals are truly astronomical in origin. Laboratory measurements confirming the existence of an additional brighter-fatter type effect in HAWAII-1RG and HAWAII-2RG HgCdTe infrared arrays with cutoff wavelengths ranging from 5.7 to 16.7 μm are presented. This effect is similar in nature to the blooming observed in charge-coupled devices and is characterized by a pixel spontaneously sharing a current with its neighbors upon reaching saturation, serving to make the brightest sources appear fatter. In addition to exploring the cause and mechanism of current sharing for this effect, measurements for several arrays show the magnitude of the shared current is greater than 60% of the incoming photocurrent hitting the saturated pixel. A proof-of-concept correction method for this effect is also described along with the necessary next steps to improve this correction and investigate the amplitude of other nearest-neighbor interactions. © 2021 Society of Photo-Optical Instrumentation Engineers (SPIE).