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ALFOSC CCD14 linearity with ccd3-controller


The x-axis shows the signal level in ADUs and y-axis the "linearity residual" (LR). The horizontal dashed lines show the +-1% level of non-linearity. The data was taken April 2016 using the beta-light source and Novemeber 2016 using the beta-light source + filters.
This indicates that the system is linear (better than +-1%) up to ~600 kADUs (full well= 135ke-/pixel, 700 kADU/pixel). The integration time are from 0.4 to 600 seconds.

The "linearity residual" (LR) equation:

LR=100(1-\frac{S_M(DN)/t_{EM}}{S(DN)/t_E})

where LR is the linearity residual at a specific signal level (%). The variables S(DN) and tE are the measured signal and exposure time (seconds). The tEM is the exposure time required to produce a signal (sec), SM at mid-scale in the plot (DN) [Taken from "Scientific Charge-Coupled Devices" pp 117 by James R. Janesick, SPIE press 2001].


More measurements based on the cryostat LEDs (Oct/Nov 2018), for various CCD setups.

Back to top Last modified: May 31 2023