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| ==== Report for the week of 3/18 ==== * BS * Terrence notice that one of the IP LVDTs was not working. We traced it to an unplugged cable, plugged it back in and screwed it together to prevent a recurrence. * Simon helped us rebuild the damaged LEN OL QPD stage and Terrence reinstalled it. We removed a C-clamp that we had been using to immobilize the breadboard because it interfered with the QPD stage, and replaced it with a more elegant solution using a dog clamp underneath. * We noticed that the BS IP had fallen over in +L at some time shortly before Nakano-san aligned the optic on 3/18. Terrence tried to recenter it but it was unstable. We decided to remove the tank lid one more time and remove some arc weights. The IP frequency had been 39 mHz the last time it was measurable, and we increased it to a much-safer 80 mHz by removing 9 kg. We believe we were able to recover Nakano-san's alignment fairly closely. * Terrence then recalibrated and diagonalized both the TILT and LEN OL. * SR2 * Terrence recalibrated the OL. * SR3 * Mark pulled out unused cables leading into the SR3 cleanbooth. * SRM * Terrence set up the SRM Guardian. * Etc/All * Mark did an audit of the OL whitening/dewhitening system and fixed a bunch of problems: the SRM chassis was the wrong type, with no actual whitening card; SR2 and SRM needed whitening filters turned on; BS LEN needed the dewhitening turned on; SR2, SR3 and SRM needed dewhitening filters installed and turned on; SRM needed more gain. * Terrence weeded out a minor error from his OL diagonalization scheme and got L, T and Y independent at the 1% level for SR2 and SRM. He will do SR3 next. * Fabian measured the gain resistor values and other settings of the LVDT drivers, in case a card or chassis fails and we have to approximate the original state without the chance to recalibrate from scratch. * Fabian monitored the pumpdown. |
==== Report for the week of 5/13 ==== Report on the simulation by Fabian: |
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| ==== Plan for week of 3/25 ==== * Mark, Fabian, Terrence at Kamioka Mon-Thu. * Assist with alignment. * Work on Type B paper. * Tidy up. * Throw out foil and other garbage. * Gather and clean tools. * Gather and organize unused parts and fasteners. * Return all unused cables to tent. * Tidy up cables in rear of SR2 rack. |
* Modified Takanori's Simulink/Matlab simulation in order to include the length sensing oplev and its control feedback path. * Imported Enzo's IM/GAS/IP-LVDT filters into the simulation. * Imported into the simulation the measured LVDT floor noise (sensitivities) and * Calculated the IP-L, IP-T and IP-Y sensitivities. ==== Report for Golden Week ==== * Mark monitored vent and pumpdown, and worked on vistools.py. ==== Report for the week of 5/6 ==== * Lucia and Terrence got the blending working for the IP LVDTs and geophones. * Terrence and Mark modified the models and MEDM screens to add a new IP block, IDAMP, for damping using the blended signal with inertial information, and a new DAMPMODE block for ramping smoothly between IDAMP and the old DAMP. * Mark worked on vistools.py, improving the support for cdsMuxMatrix blocks (e.g., OSEM2EUL) and adding support for cdsRampMuxMatrix blocks (e.g., the newly introduced DAMPMODE). He also created two sets of unit tests, unittest.py and unittest.sh, for the two modes of use (as a Python module in other Python programs, and as a command-line utility in bash). ==== Report for week of 5/13 ==== * Terrence and Mark looked at the velocity and angular velocity noise of the SR2 as reported by the LEN OL. The Y signal was fairly clean and the Y RMS angular velocity requirement was met. However the L signal was quite noisy, and was also contaminating the P signal due to the large cross terms in the diagonalization matrix. The RMS L from 5 Hz down with damping on was around 10 µm/s, which is 10 times the requirement. However little of this was due to pendulum resonances - most of the noise was featureless and broadband. In displacement units the noise was flat up to about 1 Hz and then smoothly rolled off to f^-2. The noise in the raw P and Y signals (not yet divided by the sum) was about 10 times the noise in the SUM * We tried improving the noise with different whitening settings. Increasing the overall gain, increasing it at the QPD but reducing it at the whitening filter, and switching off the 1-10Hz boost whitening filter (and compensating software filter) had no effect. Blocking the beam reduced the noise by about 2 orders and brought the raw P and Y in line with the SUM, suggesting that the problem was before the QPD. * Mark swapped in an improved version of `vistools.py`, debugged a few small issues, and simplified the `TYPEB.py` Guardian. |
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| * Enzo's final vacation till 3/29. * Terrence's last day for now, 3/29. * Mark compensation day for 3/21: 3/29. * Type B going-away party for Terrence/Enzo, 3/29 in Tokyo. * Terrence's next visit from 4/18. * Fabian's vacation 4/26 to 5/10. * Mark's final day ≈6/28 (TBD). |
* Terrence's next visit from 4/18 to 7/27. * Mark's US vacation from 5/22 to 6/11. * Mark's final day 6/28. |
Scraps of text for incorporation in the VIS Meeting Minutes
KAGRA/Subgroups/VIS/MeetingNAOJ
Type B (Mark)
Report for the week of 5/13
Report on the simulation by Fabian:
- Modified Takanori's Simulink/Matlab simulation in order to include the length sensing oplev and its control feedback path.
- Imported Enzo's IM/GAS/IP-LVDT filters into the simulation.
- Imported into the simulation the measured LVDT floor noise (sensitivities) and
- Calculated the IP-L, IP-T and IP-Y sensitivities.
Report for Golden Week
- Mark monitored vent and pumpdown, and worked on vistools.py.
Report for the week of 5/6
- Lucia and Terrence got the blending working for the IP LVDTs and geophones.
- Terrence and Mark modified the models and MEDM screens to add a new IP block, IDAMP, for damping using the blended signal with inertial information, and a new DAMPMODE block for ramping smoothly between IDAMP and the old DAMP.
- Mark worked on vistools.py, improving the support for cdsMuxMatrix blocks (e.g., OSEM2EUL) and adding support for cdsRampMuxMatrix blocks (e.g., the newly introduced DAMPMODE). He also created two sets of unit tests, unittest.py and unittest.sh, for the two modes of use (as a Python module in other Python programs, and as a command-line utility in bash).
Report for week of 5/13
- Terrence and Mark looked at the velocity and angular velocity noise of the SR2 as reported by the LEN OL. The Y signal was fairly clean and the Y RMS angular velocity requirement was met. However the L signal was quite noisy, and was also contaminating the P signal due to the large cross terms in the diagonalization matrix. The RMS L from 5 Hz down with damping on was around 10 µm/s, which is 10 times the requirement. However little of this was due to pendulum resonances - most of the noise was featureless and broadband. In displacement units the noise was flat up to about 1 Hz and then smoothly rolled off to f^-2. The noise in the raw P and Y signals (not yet divided by the sum) was about 10 times the noise in the SUM
- We tried improving the noise with different whitening settings. Increasing the overall gain, increasing it at the QPD but reducing it at the whitening filter, and switching off the 1-10Hz boost whitening filter (and compensating software filter) had no effect. Blocking the beam reduced the noise by about 2 orders and brought the raw P and Y in line with the SUM, suggesting that the problem was before the QPD.
Mark swapped in an improved version of vistools.py, debugged a few small issues, and simplified the TYPEB.py Guardian.
Vacation/Travel Info
- Terrence's next visit from 4/18 to 7/27.
- Mark's US vacation from 5/22 to 6/11.
- Mark's final day 6/28.