In support of the European space agency (ESA) Euclid mission, NASA is responsible for the evaluation of the H2RG mercury cadmium telluride (MCT) detectors and electronics assemblies fabricated by Teledyne imaging systems. The detector evaluation is performed in the detector characterization laboratory (DCL) at the NASA Goddard space flight center (GSFC) in close collaboration with engineers and scientists from the jet propulsion laboratory (JPL) and the Euclid project. The Euclid near infrared spectrometer and imaging photometer (NISP) will perform large area optical and spectroscopic sky surveys in the 0.9-2.02 μm infrared (IR) region. The NISP instrument will contain sixteen detector arrays each coupled to a Teledyne SIDECAR application specific integrated circuit (ASIC). The focal plane will operate at 100K and the SIDECAR ASIC will be in close proximity operating at a slightly higher temperature of 137K. This paper will describe the test configuration, performance tests and results of the latest engineering run, also known as pilot run 3 (PR3), consisting of four H2RG detectors operating simultaneously. Performance data will be presented on; noise, spectral quantum efficiency, dark current, persistence, pixel yield, pixel to pixel uniformity, linearity, inter pixel crosstalk, full well and dynamic range, power dissipation, thermal response and unit cell input sensitivity.
Cleanliness specifications for infrared detector arrays are usually so stringent that effects are neglibile. However, the specifications determine only the level of particulates and areal density of molecular layer on the surface, but the chemical composition of these contaminants are not specified. Here, we use a model to assess the impact on system quantum efficiency from possible contaminants that could accidentally transfer or cryopump to the detector during instrument or spacecraft testing and on orbit operation. Contaminant layers thin enough to meet typical specifications, < 0.5μgram/cm2, have a negligible effect on the net quantum efficiency of the detector, provided that the contaminant does not react with the detector surface, Performance impacts from these contaminant plating onto the surface become important for thicknesses 5 - 50μgram/cm2. Importantly, detectable change in the ”ripple” of the anti reflection coating occurs at these coverages and can enhance the system quantum efficiency. This is a factor 10 less coverage for which loss from molecular absorption lines is important. Thus, should contamination be suspected during instrument test or flight, detailed modelling of the layer on the detector and response to very well known calibrations sources would be useful to determine the impact on detector performance.
The Reionization And Transients InfraRed (RATIR) camera has been built for rapid Gamma-Ray Burst (GRB)
followup and will provide quasi-simultaneous imaging in ugriZY JH. The optical component uses two 2048 × 2048
pixel Finger Lakes Imaging ProLine detectors, one optimized for the SDSS u, g, and r bands and one optimized
for the SDSS i band. The infrared portion incorporates two 2048 × 2048 pixel Teledyne HgCdTe HAWAII-2RG
detectors, one with a 1.7-micron cutoff and one with a 2.5-micron cutoff. The infrared detectors are controlled by
Teledyne's SIDECAR (System for Image Digitization Enhancement Control And Retrieval) ASICs (Application
Specific Integrated Circuits). While other ground-based systems have used the SIDECAR before, this system
also utilizes Teledyne's JADE2 (JWST ASIC Drive Electronics) interface card and IDE (Integrated Development
Environment). Here we present a summary of the software developed to interface the RATIR detectors with
Remote Telescope System, 2nd Version (RTS2) software. RTS2 is an integrated open source package for remote
observatory control under the Linux operating system and will autonomously coordinate observatory dome,
telescope pointing, detector, filter wheel, focus stage, and dewar vacuum compressor operations. Where necessary
we have developed custom interfaces between RTS2 and RATIR hardware, most notably for cryogenic focus stage
motor drivers and temperature controllers. All detector and hardware interface software developed for RATIR
is freely available and open source as part of the RTS2 distribution.