Summary of the Nancy Grace Roman Space Telescope flight detector performance

The Nancy Grace Roman Space Telescope will study the dark matter content of the universe, the expansion history of the universe, and the diversity of exoplanets in the Galaxy using unprecedented wide-field infrared surveys. Roman will accomplish this using a focal plane of 18 newly developed HgCdTe detectors. Roman’s detectors, the H4RG-10, are 4 K×4 K format 10-micron pixel pitch devices manufactured by Teledyne Imaging Sensors. After acceptance testing at the Goddard Detector Characterization Lab, 18 flight detectors were selected for the flight focal plane. Histograms of the performance parameters of the flight detectors are provided and compared against the requirements, deriving yield statistics. The dominant yield loss was read noise (32%) rather than persistence (21%), which may be attributed to the development and use of the PV3 passivation for Roman’s sensors. The 18 flight sensors were selected and positioned in the focal plane according to sensor performance in addition to other criteria such as crosshatch and the presence of high total noise and low correlated double sample noise pixels. System-level testing of the focal plane was completed at Goddard in 2023, after which the focal plane was integrated into the Wide Field Instrument (WFI) at BAE Systems (formerly Ball Aerospace). At the end of 2023, the WFI completed its first thermal vacuum test, providing the first instrument-level performance measurements of the focal plane. In the spring of 2024, the WFI completed environmental (vibration and acoustic) testing and finished its second thermal vacuum test before being shipped back to Goddard for integration into the spacecraft assembly. We review the performance of Roman’s flight lot of detectors and early results from integration and testing.