kiwamu.izumi@LIGO.ORG - posted 04:13, Friday 14 February 2014 - last comment - 11:11, Friday 14 February 2014(10091)
TMSX red QPD centering: good enough
Yuta, Evan, Kiwamu
We steered the picomotors on TMSX again tonight to center the red transmitted light on the QPDs. After a couple of hours of struggling, we managed to bring both of them within their linear range. This is good enough for now as this should be able to monitor some alignment-related signals. The numbers below are the current picomotor settings:
M4 X = -12813, Y = 38475
M14 X = -12810, Y = -75268
Because of this alignment work, we lost the red trans signal and red trans camera view again. We don't have energy to realign them on ISCTEX table at the moment and therefore are leaving it as it is.
This morning we found the beam was clipped coming out of the viewport onto the ISC table, so we moved M4 to get it back. The current position is X:9267 Y: 1665
Also, the IR camera was moved so that the beam was directly incident on it. This doesn't work, you can't se the difference between the different modes. I put it back the way I had it set up originally, with the beam incident on the baffle and the camera focused on the baffle. This was kind of a pain to redo, Alexa and I replaced the dichroic with a green optic to find the image of the green beam, re set up the camera, then replaced the optic.
We see now flashed of up to 60000 counts on the TR X PD.
I am sorry. That's me who changed the camera setup (alog 10086).
For future reference: the CCD was OK without the TV lens last night as the camera automatically adjusts the gain. The higher spatial mode was distigushiable from the 00 mode. Also, the alignment could be done by the infrared when it is on a resonance either by ALS or infrared locking.