Virgo Logbook

As we believe that the problem is the remaining central spot at the center of the ring, we changed again the setup of the WI TCS bench. By experience, we know that this central spot is weaker when the input diameter of the ring is larger. So we moved again the lens L3 towards the axicon and realigned the setup by moving M2 and the axicon.
So the new ring can be seen on image 1. The ring with the central spot on image 2. These images have been taken at 16W. The remaining spot at the center of the ring is still there but much weaker than before.

initial positions
UL 6400
BR 700
Checked CS is centered in this position
12W WI Ring at Jan16,09-22:58:17 -> GPS: 916178312
PC_image3 23H18
moved UL 6400 to 6100 at Jan16,09-23:21:59 -> GPS: 916179734
moved BR 700 to 1000 at Jan16,09-23:22:25 -> GPS: 916179760
Increased power up to 16Wat Jan16,09-23:22:56 -> GPS: 916179791
PC_image4 23H30
moved UL 6100 to 5600 at Jan16,09-23:31:21 -> GPS: 916180296
moved BR 1000 to 1500 at Jan16,09-23:32:01 -> GPS: 916180336
PC_image5 23H40
moved UL 5600 to 4600 at Jan16,09-23:41:44 -> GPS: 916180919
moved BR 1500 to 2500 at Jan16,09-23:43:10 -> GPS: 916181005
moved UL 4600 to 3600 at Jan16,09-23:49:20 -> GPS: 916181375
PC_image6 23H50
moved BR 2500 to 1500 at Jan16,09-23:54:13 -> GPS: 916181668
closed at Jan17,09-00:01:53 -> GPS: 916182128

Not so bad!!!!