Med mode focus

We took some gas cell with rinsed cell spectra on Friday, Feb 8.  We used the pinhole arc to get readings across more of the detector.  We did 2T, 4T, 6T, 8T, 10T, and 12T.  Data were acquired using NSNSNSD.  I analyzed 2-8 using the third N differenced with the first N.  I then differenced charged and rinsed cells to get a series of spots (see clipped picture below from 6 Turns)

The spots with the red crosses were the ones fit with 2D Gaussian.  The results are below.

CLICKFIT on 2D data gives a fit along rows and columns.  In the figure above, the X axis is the column number, so we see the difference in focus caused by the tilted detector.  The different colors are for different turns:  White - 2T; Red - 4T; Green - 6T; Blue - 8T.  The dots are the FWHM along columns and the crosses are for along rows.  As a general rule, the fits along columns (spatial dimension) are generally narrower than the spectral dimension.

I'd say 2T is safely out.  Looking at the spatial, I'd say 6T is closest to where the focus is best near the middle.  This is mostly because 4T and 8T have larger excursions near the ends.  This is a couple turns further out than Curtis found with the odd/even impacted data.  The 6T spectral looks better than the 8T, although I could be convinced that the 8T is more centered.  

I think I'd go with the 6T as our starting point for the High-Med mode.