camilla.compton@LIGO.ORG - posted 10:43, Tuesday 16 September 2025 (86962)
Beam Profiles Taken of MC REFL on IOT2L
Sheila, Elenna, Camilla. WP#12797 . IOT2L layout D1300357
We took the PSL input power down to ~100mW, locked out the rotation stage and then used the nano scan to take some beam profiles in the IMC REFL path on IOT2L. Elenna and Sheila also moved a beamdump to fully block the MC REFL rejected beam that was getting on the MC REFL camera.
| Location | D4 Sigma A1 Horizontal (um) | D4 Sigma A2 Vertical (um) | D4 Sigma A1 at 45deg (um) | D4 Sigma A2 at 45deg (um) |
| A: Profiler 11 3/4" upstream of IO_MCR_BS1 | 4685 | 4240 | 4345 | 4450 |
| B: Profiler 10 1/16" downstream of IO_MCR_BS1 (7" + 1 1/4" + 1 13/16") | 4678 | 4647 | 4605 | 47921 |
| C: Profiler 14 1/2" downstream of IO_MCR_BS1 (7" + 1 1/4" + 6 1/4") | 4800 | 4807 | 4784 | 4676 |
By eye the beam looked gaussian and the numbers show it is mainly symmetric. Maybe last measurements where when the WFS were being installed in 2013 6439.
For positions B and C, we added a temporary steering mirror between IO_MCR_M7 and IO_MCR_L2. Distance between IO_MCR_BS1 and IO_MCR_M7 = 7"; Distance bewtween IO_MCR_M7 = 7" and temporary steering mirror = 1 1/4".
Images attached to this report
