[Dsg-rich] RICH spherical mirror 4 reflectivity test

[Marco Mirazita]

Hi Tyler,
thank you for the data, the fact that the smudgetd spot has the highest 
reflectivity is definitely strange.
And 95% reflectivity looks to me too high.
By looking at the data, it seems that the measurements from Aug. 18 have 
much larger variations in the photodiode A (the reference) than in the 
previous data taken with mirror 3.
See the attachment.
Also, spot 2 has much lower reflectivity, I wonder how the surface on 
this spot looked visually.
Best regards,
Marco


Il 2017-08-18 22:20 Tyler Lemon ha scritto:
> Hello,
> 
> This afternoon, Mindy, Amanda, and I tested three additional spots on
> Mirror 4 with the reflectivity test station.
> 
> The location of the three additional spots are noted in the updated
> "Mirror 4 reflectivity test locations.JPG" that is attached. We were
> not able to measure any spots where the worst smudges are on the
> bottom of the mirror surface due to the placement of the test
> station's optics and the size of the darkbox.
> 
> Attached are the excel sheets for all five spots: two from yesterday
> and three from today.
> 
> Spot 3 was on an area of the mirror that looked smudged. However, the
> results for this mirror unexpectedly gave a reflectivity of 92% - 94%
> for wavelengths 420 nm to 650 nm. This was higher than spots 4 (89% -
> 91%) and spot 5 (88% - 90%).
> 
> Best regards,
> 
> Tyler
> 
> -------------------------
> 
> FROM: "Tyler Lemon" <tlemon at jlab.org>
> TO: "dsg-rich" <dsg-rich at jlab.org>
> SENT: Thursday, August 17, 2017 5:00:00 PM
> SUBJECT: [Dsg-rich] RICH spherical mirror 4 reflectivity test
> 
> Hello,
> 
> This morning Mindy and I took reflectivity measurements for RICH
> spherical Mirror 4.
> 
> As the mirror will soon be shipped to CMA, we wanted to finish taking
> reflectivity measurements for Mirror 4 to give us a reference for the
> mirror when it returns to JLab.
> 
> We measured Mirror 4's reflectivity in two spots. The location of
> these spots are noted in the attached "Mirror 4 reflectivity test
> locations.JPG".
> 
> Just looking at the data, Mirror 4's reflectivity for spot 1 is
> between 87% - 89%.
> 
> For spot 2 the reflectivity is between 79% and 81%. The lower
> reflectivity for spot 2 could be from an area of poor surface quality
> or a misalignment in the test station optics.
> 
> Best regards,
> 
> Tyler
> 
> _______________________________________________
> Dsg-rich mailing list
> Dsg-rich at jlab.org
> https://mailman.jlab.org/mailman/listinfo/dsg-rich
> 
> _______________________________________________
> Dsg-rich mailing list
> Dsg-rich at jlab.org
> https://mailman.jlab.org/mailman/listinfo/dsg-rich
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 2017-08-21_reflectivity.pdf
Type: application/pdf
Size: 102150 bytes
Desc: not available
URL: <https://mailman.jlab.org/pipermail/dsg-hallb_rich/attachments/20170821/259866ec/attachment-0002.pdf>