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| ==== Report for the week of 3/11 ==== * Fabian helped Fujii-kun with the PRM most of the week. Hirata-san also helped at various times. * Fabian monitored the SRM yaw drift. It gradually reversed but so far remained small. We will try resetting it to zero with the pico and see if the trend changes. * Mark and Hirata-san debugged the BS: * We inspected the payload section and quickly found the problem: two RM EQ stops were touching, on the +L (-X,+Y) side at the top. This was probably because the stops had been adjusted with the IP unlocked and sitting a few mm to -L, whereas now we have the DCCTRL running and have been locking the IP at the LVDT zero. We drove the IP to L=+1.5 mm as a near-worst case, and backed off all the stops to give several mm of margin. Then we zeroed the IP pitch, roll and yaw with the picos. * We also opened the top of the BS and confirmed that the mechanical zero defined by the locking mechanism agreed with the LVDT zero. It was very close in L and T, but -728 µrad in Y, driven mostly by a -805 µm offset in H3. That much is probably not a dumb error but just a difference in technique among the three people using calipers to take data for the calibration. * We then prepared the BS for close-up: * We wiped and inspected the O-ring for the lid and replaced the lid. * We wiped all accessible surfaces in the lower half of the tank, rescued some dropped items (some PEEK tube and a small nut) and un-immobilized the LBB. * After all the above, the OL was a bit off-center but still on the QPD, and Nagano-san fairly quickly recovered the original alignment. * Terrence rebuilt the BS TILT OL according to a new layout suggested by Simon, which avoids scrambling the pitch/yaw at the first steering mirror and greatly reduces the amount of diagonalization required. He started on the LEN OL, but unfortunately the QPD stage fell and bent the brackets holding two of the micrometers. It's useable but we haven't installed it yet. * Terrence noticed some anomalous cross coupling on the SR2 (but not the SR3) and we investigated. * We suspected it might be an odd position of the beam spot on the optic, so we took pictures through the camera and LED viewports of SR3, and opened the SR2 tank and used a white target, but the beam spots were in very similar positions - close to central vertically and about 3 cm to the left of center horizontally. * We suspected it might be something touching at the IRM (because the IM OSEM TFs were fine), so we checked using a stick mirror with the IP centered, but all EQ stops were well backed off. * We suspected it might be a ghost beam from the LEN/TILT beamsplitter (and one was clearly visible on the SR2 TILT QPD) so Terrence set up a beam block, which improved things slightly but not completely. * Finally Terrence discovered that the problem was mainly uneven sensitivities of the QPD quadrants, and devised a new calibration procedure which allowed for it. Later we discovered that one of the 3 dB gain stages on the whitening filter was engaged, even though the switch on the BIO Config card was not. It mysteriously came good after we removed and replugged the card. * Enzo and Terrence did a health check of the SRM and it was fine except for some apparent electrical noise around 240 Hz. They put in a notch filter to get rid of it for now. |
==== Report for the week of 3/25 ==== * Mark and Fabian helped Fujii-kun with PR2. The problem turned out to be two broken flags. Hirata-san drew up a design for a jig to help reglue the flags in situ. * Fabian documented the height budget for the Type B suspension in the wiki ([[KAGRA/Subgroups/VIS/OpsManual/TypeB/SR3Data]] etc). * Terrence wrote up the final version of his OL diagonalization scheme. * Terrence worked on L2P decoupling for the TM. * Terrence and Mark edited the Type B Guardian to turn on the payload damping later in the sequence, after IP and GAS, to help ensure that the OSEMs are not touching by the time they're needed (which can happen if the BF is buoyancy compensated for vacuum but the suspension is vented). * Mark started on a big tidy-up of the cleanbooth. * Mark asked LIGO colleagues about use-by dates for EP30-2. Masterbond says it's good for 6 months in cartridge form and 12 months in jar form (although presumably only if the jars are not opened). If it's too old it may remain tacky after curing. The batch that Type B has was manufactured 2017-11-02 and KEK has a batch from early 2018. |
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| ==== Plan for week of 3/18 ==== * Mark, Fabian, Terrence at Kamioka full week. * More OL stuff. * SRM controls and Guardian. * Reset SRM yaw and continue monitoring yaw drift. * Assist with pump down. |
==== Plan for week of 3/25 ==== * Mark, Fabian at Kamioka Mon-Fri. * Assist with PR2. |
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| * Modify RT models and/or Guardian to revert to the SAFE state under control in all but the most extreme emergency situations (rather than suddenly shutting off all output). | |
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| * Throw out foil and other garbage. | |
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| * Pull out unused cables in cable tray near SR3. | |
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| * Enzo at JPS then final vacation, 3/13-29 * Terrence's last day, 3/29. |
* Enzo's last day 3/29. * Terrence's last day for now, 3/29. * Mark compensation day for 3/21: 3/29. (He is not really typing these minutes, and anyone who sounds like him in the meeting is an impostor!) * 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 vacation from about 5/22 to 6/11 (TBD). * 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 3/25
- Mark and Fabian helped Fujii-kun with PR2. The problem turned out to be two broken flags. Hirata-san drew up a design for a jig to help reglue the flags in situ.
Fabian documented the height budget for the Type B suspension in the wiki (KAGRA/Subgroups/VIS/OpsManual/TypeB/SR3Data etc).
- Terrence wrote up the final version of his OL diagonalization scheme.
- Terrence worked on L2P decoupling for the TM.
- Terrence and Mark edited the Type B Guardian to turn on the payload damping later in the sequence, after IP and GAS, to help ensure that the OSEMs are not touching by the time they're needed (which can happen if the BF is buoyancy compensated for vacuum but the suspension is vented).
- Mark started on a big tidy-up of the cleanbooth.
- Mark asked LIGO colleagues about use-by dates for EP30-2. Masterbond says it's good for 6 months in cartridge form and 12 months in jar form (although presumably only if the jars are not opened). If it's too old it may remain tacky after curing. The batch that Type B has was manufactured 2017-11-02 and KEK has a batch from early 2018.
Plan for week of 3/25
- Mark, Fabian at Kamioka Mon-Fri.
- Assist with PR2.
- Work on Type B paper.
- Modify RT models and/or Guardian to revert to the SAFE state under control in all but the most extreme emergency situations (rather than suddenly shutting off all output).
- Tidy up.
- 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.
Vacation/Travel Info
- Enzo's last day 3/29.
- Terrence's last day for now, 3/29.
- Mark compensation day for 3/21: 3/29. (He is not really typing these minutes, and anyone who sounds like him in the meeting is an impostor!)
- 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 vacation from about 5/22 to 6/11 (TBD).
- Mark's final day 6/28.