[Dsg-rich] Reflectivity test station - alignment tests

[Tyler Lemon]

Hello, 

Attached is an Excel sheet containing the results from today's alignment tests of the reflectivity tests station. The sheet contains the three data sets for separate calibration and reflectivity tests of the control mirror. After the three sets of results, there are statistics showing the mean photodiode currents, reflectivity, and percent error for a wavelength. 

The procedure for taking each measurements was: 
1.) Align test station to take calibration run. 
2.) Take calibration run. 
3.) Re-align test station to measure mirror. 
4.) Take mirror measurement run. 

Between measurements, we noted that the lamp power remained at 10.65V and 3.84A. We did not turn the lamp or picoampmeter off between measurements. 

The calculations at the end of the data show that there is a higher error of all measurements compared to yesterday's tests when the test station was not modified between measurements. Yesterday, the errors for calibrations were under 1%. Today, the errors for calibrations were about 6%. There are some exceptions at smaller wavelengths (300nm - 400nm) where the error for the calibration is greater. 

The calculations also show that the control mirror's reflectivity measurements had an error of about 6% for most wavelengths. Again, there are some exceptions for reflectivity measurements at smaller wavelengths (300nm - 420nm) where the error for the reflectivity was greater. One major exception was that the reflectivity measurement at 420 nm had an error of ~20%. This measurement is highlighted in orange in the table. 

In conclusion, today's results further support that the main source of error in the test station is in how repeatable the test station optics's alignment is between data runs. 

Best regards, 
Tyler 

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