Matteo, Eleonora, Simon

With the alignment set yesterday and the day before (see log entries 1448 and 1445), we were able to start with inserting a sapphire mirror (SHINKOSHA, No. 7). We are using this mirror as a kind of a test-sample to check whether the system is giving reliable data since this sample has been measured already in the past.
 

• We removed the silica mirror from the mirror-holder (that one is now stored in the small shelf inside the clean-room - be very careful when moving around as it is easy to hit!!!)
• We took the sapphire mirror from its container and put it inside the mirror-holder (see attached pictures)
• For placing the mirror-holder inside the transition-stage, we removed the protection-shield around the detector-bench, relocated the imaging units of both red and IR (red -> 6.7mm), and moved the translation-stage to a convenient position
• Then, we placed the mirror-holder on the translation-stage
• After that, we put the protection shield

Note: In order to have enough clearance for the mirror (thickness ~15cm), we removed the IR imaging-unit later on

Once the mirror was set, we started a checkup measurement to compare our setup with measurements from the past:

• Setting the border-limits to define where the mirror starts and ends in Y and X direction
• Readjusting the imaging-unit to have a maximum in DC
• Run horizontal measurements to obtain the coordinates of input and output surface with ~1W of input power in the center
• Run horizontal measurements with 10.47 W of input power to check all initial settings (see screenshot)

With the results, we confirmed an absorption coefficient of ~130 ppm/cm which is in agreement with Manuel's measurements (~119 ppm/cm mean value over an entire map)

Then, in the afternoon, we started to take a X-Y absorption map in the center of the mirror (anticipated duration ~14h). That should be finished by tomorrow.