Speaker
Description
In this work, we studied the tree-rings in the LSST camera. Specifically, we compared the tree-rings observed in flat images under the normal operating voltage back bias and under a 0-volt back bias. We showed that tree-rings in the 0-volt back bias flat images have higher signal-to-noise ratios (SNR) and are more easily detectable, which therefore can be used to better infer tree-ring centers. However, we demonstrated that there is a large scatter in the relationship between the tree-ring amplitudes in the normal operating voltage and the 0-volt back bias images. This scatter presents a difficulty in estimating the tree-ring profiles using the higher SNR measurements from the latter images, but it may be resolved by further studies on the systematics and noises in the flat images. Meanwhile, we estimated the characteristic tree-ring amplitudes under normal operating voltage in the LSST camera to be $\lesssim$ 0.03%. We also observed wavelength-dependence of the tree-ring amplitudes, particularly in the UV-band of the E2V sensors.
Keywords for your contribution subject matter (this will assist SOC in accurately characterizing your contribution)
Tree-ring; LSST Camera
| contribution subject matter | CCD sensors |
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