Monday, July 6, 2009

Changing the Time Constant and Taking More Scans

As I mentioned yesterday, I wanted to take some more precise scans today (Friday) and also learn how to plot the ratio of the two scans via MATLAB. I was able to take data at all five postions mentioned earlier:

(0,0)
(+HM,0)
(-HM,0)
(0,+HM)
(0,-HM)

I changed the time constant from 1 second per point (as we used earlier this week) to 100 ms. This changed the length of the scan to take about 9 min instead of the 90 min from earlier in the week. I took four scans at each of the above positions using the positions of FWHM that Antoine had determined. The only problem that I ran into was the position for the (0,+HM) gave scans a lot different from the others and the position was about 0.5 mm different from what I estimated on my initial data. Because of this, I took one more scan at the point I had expected the FWHM to be at. I labelled this point as:

(0,++HM)

For the first five positions listed above, I took data in a cyclic permutation, but for the point (0,++HM), I just took the four scans all right after each other.

During these scans, I was able to update my lab notebook and I made a note to look at how a Fabry-Perot effect might alter this data.

I tried to learn how to take the ratio with MATLAB but was unsuccessful. I talked to Guilhem about this and he gave me some commands to use. I plan on trying this out either this weekend or sometime next week. I should also have plots of the data early next week.

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