WFC3 IR Gain Monitor
Abstract
Gain, the conversion factor from electronic analog digital units (ADUs) to electrons, is a fundamental parameter needed to characterize the WFC3 IR detector. In order to ensure that the true value of the gain in each quadrant does not deviate significantly from the nominal gain setting of 2.5 e-/ADU in the WFC3/IR data reduction pipeline, it must be monitored each cycle. We propose an observing program for the IR channel of WFC3 that will measure the gain in each of the four quadrants of the detector with a series of flat field pairs taken no more than a week apart. For each quadrant of each ramp pair, the measured mean signal is plotted against the variance. The gain is the inverse of the slope of the best fit line. This proposal is an identical continuation of Cycle 25's program 14988. Ramp pairs are taken twice a year, providing two seperate calculations of gain each cycle.
- Publication:
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HST Proposal
- Pub Date:
- November 2018
- Bibcode:
- 2018hst..prop15580K