REVISION DATE: 31-Oct-2017 11:44:45

Mikes data set looking at the effect and reduction in signal using an iris on Tracks 1, 9, 11 and 13. All my ratios and signal reduction math is done on the Net signals (dark subtracted and divided by integration time). Also note that there are 2 causes of the signal being reduced. One is putting the Iris block in. Even fully open the signal is Reduced by ~2.5x and then Mike did additional adjustments to the iris to get the Es down by ~100x and the Lu channels down by ~40x.

File#1 has non-iris tracks 2:8 10, 12 and 14. Track 1, 9, 11 and 13 have the iris installed. So the first question is what is the reduction caused just by the iris being in place and fully open. As Mike says "Adding the iris, even with the iris fully open, attenuated the light signal by ~2.5 x by my reckoning." When I do the math on file#1 I get a 3.1x reduction. This was calculated by looking at the ratio of all the combinations if Iris tracks to non-iris tracks and then calculating a mean of all these ratios.

Figure 1

Next Mike wanted to confirm the amout of reduction the iris was capable of. So he close the iris completely. This graph shows the reduction in signal for a closed iris for Track 1, 9, 11 and 13.

Figure 2

Next Mike wanted to adjust Track 1, the Es track, by 40 times. So this measures the reduction he got on Track 1. He got close at 29 times less signal.

Figure 3

Next Mike wanted to adjust Track 9,11 and 13, the Lu tracks, by 4 times. This shows the reduction, looks like Mike is right on ~3.8 - 3.9 signal reduction.

Figure 4

A check of the final Iris adjustment changes for track 1, 9, 11 and 13. Looks good.

Figure 5

Checking the full reduction from no iris to the iris with Mikes adjsutments. It is 10x for the Lus and ~80x for the Es.

Figure 6