During the late afternoon of Jan 6/7, 2019, several of the RIT students (Marko Ristic, Teresa Symons, Kain McCall) took a series of dome flatfield images, varying both the lamp settings and exposure time in order to acquire images with a large range of light levels. We used the default amplifier 'ur' in single-amp mode, and the V-band filter.
We followed the procedures outlined in earlier measurements of gain
Below are the results of this set of exposures.
If one fits a line to the measurements with mean values between 0 and 30,000 ADU (= 15,000 ADU/2), one finds a formal result of
gain = 1.46 +/- 0.06 e-/ADU
Marko Ristic, Teresa Symons, and Brent Neves performed a similar analysis independently, using somewhat fewer measurements in each pair of images. They found values of gain between 1.35 and 1.45 e-/ADU, which are consistent with the value shown above.
This measurement is slightly higher than the values derived in tests in past years, which are about 1.3 e-/ADU.