Thursday ETMY HWS notes
0934 – at etmy. Going to work on imaging first using the sharpness of the baffle shadow as a guide.
0940 – removed hartmann plate. Ready to take images.
Ruler, GPS time of image
77mm, 1255365740
44mm, 1255365872
100mm, 1255365916
150mm, 1255365961
191mm, 1255366027
230mm, 1255366071
0953 – back to corner station to analyze the data
1032 – not 100% clear but minimum looks to be at 90mm, with uncertainty of +/- 10mm.
So put it camera at 100mm to account for additional 10mm between Hartmann plate and the CCD. Leaves an uncertainty of ~ +/-6m from the test mass.
1117 – back at ETMY
1122 – FC/APC coupler installed. No change in the amount of power on the CCD
1127 – Using the pico mirro furthest from the periscope, I can move the beam around. When intensity is centered on the shadow, I can see clipping in the top left hand corner which gets much worse when I move it that way. Effect is asymmetric. I Do not see the same effect when moving it in the opposite direction.
1200 – 2.70units to 3.23units on translation stage
1210 - Back to 3.0units – 1255374607 to make a smaller beam. Trying to cover a range of 5mm on CCD = 110mm on ETM
1213 – Hartmann plate reinstalled.
1214 – door on
1215 – running HWS code
SSF = 2Hz, ----
1219 – Front end is down
_- Smaller beam helps a lot in making return beam look better
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1344 – Back from lunch
Going to redo imaging
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YAW0 = 128, YAW1 = 138
Z = 100mm
Dx = 5.05pixels
Z = 140mm
DX = 3.343
Z = 180mm
DX = 1.963
Z = 220mm
DX = 0.703
Z = 230mm
DX = 0.21
Z = 260mm
DX = -0.831
Zero crossing = 236.5
With plate = 246.5;
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1424 - New position – 1255382646
1505 – Going to clean fiber laser end.
1525 – Fiber cleaning only helped a tiny bit
1530 - 1255386598 – Intensity distribution
1536 – added iris to front of CCD
1537 – reinstalling Hartmann plate
(Z = 245mm on ruler)
1539 – Hartmann plate is on
1544 - Frame rate = 1Hz, 262 centroids, peak value = 2840
1255387575 – ETMY RH set from 0.8W to 4.8W
1547 – Changed ETMY magnification to 22.8x
See if can hook up remote control tomorrow.
How robust is launcher to misalignment/bumping?
Here is an image of the intensity profile on the ETMY HWS. It's the closest to a Gaussian beam that we've seen on any of the ETM HWS before.
This was mostly achieved by adjusting the translation stage of the focussing lens in the fiber launcher. Moving the lens further away from the fiber allowed us to create a smaller beam (at the expense of some mode-matching through the system).
The ring heater measurement looks promising. There are some bits of systematic noise near the edges but the central region of the wavefront looks a lot cleaner than yesterday.