Georgia, Camilla. Follow on from alog 61638. Refer to this diagram for mirror numbers. Last realigned in alog 58547.
Today we found the HWSY beam was very misaligned and clipping at M3 see photo and beam on camera. This is expected as the beam is larger than lots of the 1" optics.
We realigned as best we could using M5, M4, M3, M2, M1A. Image of beam attached. We've put the plate back on the camera and will run ring heater tests Monday morning.
I took some pictures of optics the beam is overfilling. When we talk about the beam being too large, it's not just larger than the usually acceptable 1/3 of the mirror diamater, it's larger than the mirror and in some cases the mount. The problem optics are HWS_M1c, HWS_M2, HWS_M4, and HWS_M5. See attachments.
I've been thinking about why we need to realign this path every year or so and I think it's not too surprising because there's such a long arm to the test mass and the temperature at the end station fluctuates.
We left the picomotors at the values below, these do not relate to previous values as we adjusted them by hand.
| Pico #5 (HWS M2) | -50, 300 |
| Pico #6 (HWS M1A) | 900, -1300 |
Attached plots of this morning's ETMY ring heater test. We are still seeing the opposite sign than is physical. You can see we start seeing a heating pattern after ~45minutes but it gets much clearer at the end of the 2 hour test. It takes ~1hr30 after the test finished before the heating is less clear. Ran: python3 /opt/rtcds/userapps/release/tcs/common/scripts/power_adj_scripts/ring_heater_schedule.py ETMY -s 1328890800 -d 2 -p 0.5
I had a look at the ETMY HWS measurement of the ring heater thermal lens. There is a negative lens that develops with approximately the correct time scale. It is, however, extremely noisy.
If we compare this measurement to a previous measurement on a ITMY:
- This measurement: approximately -50uD for 1W of applied power (for a double-passed (DP) measurement), or about -50uD/W DP
- Previous measurement: approximately -30uD for 2W of applied power (for a single-passed measurement), or about -30uD/W DP
This RH measurement passes a santy check for sign and magnitude.
