Reports until 14:28, Friday 09 April 2021
H1 AOS (TCS)
georgia.mansell@LIGO.ORG - posted 14:28, Friday 09 April 2021 - last comment - 15:19, Friday 09 April 2021(58547)
EY Hartmann alignment work today

Camilla, Georgia

Today's goal: Align ETMY such that there is a return beam. Following on from alog 58522. Refer to this diagram for mirror numbers.
 
Camilla steered HWS S2 to center the beam on the iris before HWS-BS2, and on HWS M5.
 
We steered HWS M4 to center the beam on HWS M2 (it’s a 1” optic with a >1” beam so there is some clipping). This also centered the beam on the iris between HWS-L2, HWS. Beam is clipping on the dog leg - HWS M1B and HWS M1C which is giving an egg-shaped beam going into the vacuum.
 
Removed the Hartmann plate from the camera (dot on top left). This one is the old design, where the spacer plate is bolted to the camera body, so when we took off the outside plate, the thin dot-array-plate is exposed, see first attached pic.
 
Had trouble streaming - images were choppy and streaked, like in the dark images we tried to take on EX. Camilla init’d the camera and ran pkill python, this cleaned up the stream.
 
Found the HWSEY picos labelled incorrectly on the Y PICO A medm screen: HWS M1A is labeled as #7, HWS M2 is labelled as #8. In reality HWS M2 is pico #5, HWS M1A is pico #6. Maybe this is something that needs to be fixed in Beckhoff?
 
Return beam looks saturated and small compared to Aidan’s alog, Camilla grabbed a screenshot. When we misaligned the TMS (significantly!) the beam went away so it is coming from in vacuum. Switched frame rate from 1Hz to 58Hz, this helped with the saturation, but the beam looked too dim so we put the frame rate back.
 
Try to fix egg-shaped beam by recentering on HWS-M5, didn’t make it any better (maybe worse??). 
 

We re-attached the Hartmann plate and ran a ring heater test, we don't see the ring heater on the Hartmann quiver plots so something is wrong.

Note: we have left the HWSY laser source on, if this causes problems for ALS someone will need to go to the end station and switch it off.

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aidan.brooks@LIGO.ORG - 14:50, Friday 09 April 2021 (58548)
Link

FYI - images appear choppy and streaked when two processes are simultaneously trying to access the images stored in the capture card memory space. Likely candidate is a "python run_HWS" process running in a TMUX session.

camilla.compton@LIGO.ORG - 15:19, Friday 09 April 2021 (58549)
Link

Thanks for the tip Aidan, that must have been the case as we ran a pkill python which solved the problem.

Photos attached showing our 1st "aligned beam" and the final alignment through the hartmann plate (didn't take a photo before replacing the plate but it almost looked like an upside down version of our first alignment which is a little strange).

Before we had any return beam on the camera there was some strange streaks, at the time we thought it could have been something wrong with the camera but it could have been a tiny bit of misaligned return beam.  

4th and 5th: Photos of signage added to ISCTEY as stated in TSOP M1900163. As Georgia says the laser diode is on and cannot be turned off remotely. 

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