Kavli Affiliate: Gabor Furesz
| First 5 Authors: Christopher Layden, Jill Juneau, Gustav Pettersson, Nathan Lourie, Benjamin Schneider
| Summary:
The Teledyne COSMOS-66 is a next-generation CMOS camera designed for
astronomical imaging, featuring a large-format sensor ($8120 times 8120$
pixels, each $10 mu m$), high quantum efficiency, high frame rates, and a
correlated multi-sampling mode that achieves low read noise. We performed a
suite of bench-top and on-sky tests to characterize this sensor and analyze its
suitability for use in astronomical instruments. This paper presents
measurements of linearity, conversion gain, read noise, dark current, quantum
efficiency, image lag, and crosstalk. We found that the sensor exhibits
nonlinear response below 5% of saturation. This nonlinearity is plausibly
attributable to the trapping of electrons in each pixel. We developed and
implemented a pixel-by-pixel nonlinearity correction, enabling accurate
photometric measurements across the dynamic range. After implementing this
correction, operating in the correlated multi-sampling mode, the sensor
achieved an effective read noise of $2.9 e^-$ and dark current of $0.12
e^-/pix/s$ at $-25^circ C$. The quantum efficiency exceeded 50% from 250 nm to
800 nm, peaking at 89% at 600 nm. We observed significant optical crosstalk
between the pixels, likely caused by photoelectron diffusion. To demonstrate
the sensor’s astronomical performance, we mounted it on the WINTER 1m telescope
at Palomar Observatory. These tests confirmed that the linearity calibration
enables accurate stellar photometry and validated our measured noise levels.
Overall, the COSMOS-66 delivers similar noise performance to large-format CCDs,
with higher frame rates and relaxed cooling requirements. If pixel design
improvements are made to mitigate the nonlinearity and crosstalk, then the
camera may combine the advantages of low-noise CMOS image sensors with the
integration simplicity of large-format CCDs, broadening its utility to a host
of astronomical science cases.
| Search Query: ArXiv Query: search_query=au:”Gabor Furesz”&id_list=&start=0&max_results=3