[dsg-hallb_rich] d0 tests repeated for mirror 5 and 5C

[Tyler Lemon]

Hello,

This morning Mindy and I repeated d0 tests for RICH spherical mirror 5 and 5C with both mirrors in the horizontal and vertical position while testing whether the ambient light background or time CCD is active have an effect on the measurement.

Before each set of mirror measurements, we took a new background image for use with that set of data.

The first measurement was taken of mirror 5C in the horizontal position with the room in the same conditions as the last week's measurements.

Next we eliminated as many sources of ambient light as possible, repeated the measurement of 5C in horizontal position, then measured 5C in the vertical position, switched mirror to measure 5 in the vertical position, and finally measured 5 in the horizontal position.

When comparing background images for without and with ambient light sources covered, CCD pixel counts were an average of 0.13 +/- 2.39 counts lower when ambient light was eliminated (histogram in Fig 1).

When comparing the first no-ambient-light background with the last no-ambient-light background (~1 hour 15 minutes later), the CCD pixel counts for the last background measurement were an average of 0.36 +/- 2.38 counts lower (histogram in Fig 2).

>From these results, I do not think that leaving the ambient light in the room affects the background data too much. However, I do think that it is a good idea to take the multiple background measurements for each set of measurements.

The table below has the results of the d0 test for each mirror.

Mirror
Position
Ambient Light Eliminated?
Lowest d0 Observed [mm]
Fit d0 [mm]
Fit Mirror Radius of Curvature [mm]
5C
horizontal
No
1.969   2.12
2708.1
5C
horizontal
Yes
2.008
2.16
2708.23
5C
vertical
Yes
2.989
3.01
2702.15
5
horizontal
Yes
2.468
2.81
2709.8
5
vertical
Yes
2.670
2.69
2704.26

Because the PDFs of the results are each ~10 MB, I have put them on my JLab userweb page at the link below.

https://userweb.jlab.org/~tlemon/RICH/RICHII_mirrors/

-Tyler
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