KAGRA MIR (Absorption)
SimonZeidler - 10:55, Thursday 20 February 2020 (2050)
Test absorption measurement after upgrade

Pengbo, Simon

After having found a good calibration for the upgraded system, Shinkosha#7 has been characterized again in terms of absorption (input P-polarization). The results can be seen in the attached figures (Z = 76), compared to the ones before the upgrade (Z = 74.1).
The basic shape as well as the mean aborption coefficient are almost the same, which is a very good achievement.
However, there are also small differences. It seems that the center absorption, which is at maximum in both measurements, is higher than before the upgrade. Also, there are basically two peaks in the absorption-coefficient distribution for yesterday's measurement. The reason is not clear. Maybe the change in polarization has some effect on the results. We are going to further analyze this phenomenon by using a polarization control on the pump-beam.

Images attached to this report
2050_20200220025520_figure1.png 2050_20200220025525_figure1abstest.png 2050_20200220025535_figure2.png 2050_20200220025541_figure2abstest.png