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| ==== Report for week of 12/17 ==== * BS * Miyakawa-san worked on the BS real-time model and the gain/offset settings for the F0 LVDTINF block were lost, so we reentered them and did a new safe.snap file. * SRM * We unlocked the IP adjusted the level with the jacks to center it. As hoped, this also improved the alignment of the chain insecurity structure and fixed a touching issue. * Hirata-san installed and cabled the new F0 yaw stepper. We had allowed plenty of reserve mass, so there was no problem getting back to nominal height of the keystone. [''As of Thursday afternoon, it had not yet been tested - UPDATE?''] * We found that the Nikhef method Fabian had used to tune the F0 LVDT driver gave an artificially narrow working range, so he retuned it with Enzo's method and recalibrated the LVDT. * Fabian did a vertical position survey with all the GAS filters at nominal and found the height of the RM above the SS bottom plate was about 2.5 mm lower than in the CAD. This is about what we expected from a chain 7 mm longer than CAD and and F0 keystone set to 5 mm higher than CAD. In future we can survey to either the optic or the security structure as convenient, and we are in the range where we should easily be able to match the correct beam height with the jacks under the PI. * We got two OL viewports for SRM from Akutsu-san, and will install them sometime in January, whenever we have a free moment. Akutsu-san pre-torqued the inner ring of screws around the glass, so we only need to torque the outer bolts. * We took transfer functions for the IM. All of them look good except IM-T. We will inspect the payload next week in case anything is touching or rubbing. * Hirata-san opened the +X door of the vacuum chamber for visual inspection. We closed it back and covered with tape a small gap at the door. * SR3 * We also got a camera viewport for SR3 from Akutsu-san and will install it sometime in January. * Hirata-san installed and cabled the new F0 yaw stepper. * SR2 * Enzo calibrated the SR2 OL. He noted that with the standard f=2500 mm collimator, the angular range was only about 100 µrad in pitch and 150 µrad in yaw, which is rather less than Enomoto-kun's preferred range of more like 400 µrad, so we borrowed f=1100 mm and f=3500 mm collimators to characterize. [''Enzo was going to do f=1100 mm and maybe f=3500 mm on Friday morning 12/21 - UPDATE?''] * Hirata-san installed and cabled the new F0 yaw stepper. We did not have enough reserve mass for SR2, so to save 300 g we had Mesco make a new, lighter top plate, and Hirata-san ultrasonically cleaned it. We were then able to get the desired F0 keystone height with about 200 g to spare. * The RM was touching the security structure due to a large yaw displacement. We were able to move it free by adjusting the cylinder with the spring and leaving the stepper motor in its nominal position. The f=1100 mm collimator was installed and the QPD was calibrated. * Etc * Enzo did a historical survey of the temperature as the various suspensions were being built and concluded that ideal operating temperature would be 25°C in the BS/SR2 area and 24°C for SR3/SRM. * Mark wrote a bash script to log all the GAS filter heights and LVDT actuation offsets, and an Excel spreadsheet to analyze the data to get an overview of the heights of the suspensions and the amount of height adjustment being used. He also reviewed old TF data to get near-DC values for the effect of GAS actuation on GAS height. This uncovered a few issues with calibration settings (such as for BS F0) having been lost because they hadn't been recorded in a safe.snap file, which we fixed. |
==== 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. |
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| ==== To-Do Lists, Schedule ==== * [[KAGRA/Subgroups/VIS/TypeB/ToDoBS]] * [[KAGRA/Subgroups/VIS/TypeB/ToDoSR]] * [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=7779|JGW-L1807779 Type B Schedule (SR)]] |
==== 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. * Work on Type B paper. * Tidy up. * Throw out foil and other garbage. * Gather and clean tools. * Gather and organize unused parts and fasteners. * Pull out unused cables in cable tray near SR3. * Return all unused cables to tent. * Tidy up cables in rear of SR2 rack. * |
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| ==== Plan for week of 12/17 ==== * Final alignment of SRM payload, plus BF and SF GAS. * (Time permitting) unlocking/centering/tuning of IP. * Installation of Enomoto-kun's beam target on SRM (if available). * Installation/testing of F0 steppers on SR2, SR3, SRM, and (hopefully) final vertical height adjustment. * Installation of viewports on SRM. |
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| ==== Plan for week of 12/24 ==== * Mark and Hirata-san on holidays, Enzo at Mitaka, Fabian. |
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| ==== Plan for week of 1/7 ==== * Make sure BS is floating, recenter OL to capture current yaw position. * Vent BS. * Inspect BS F0 blades for cracks. * Install new BS F0 FR, and (if necessary) auxiliary CuBe spring. * Confirm geometry of LVDTs, geophones, FRs etc and update T1707205 if necessary. * Replace geophone preamps and cables (to fix noise, offset, pinout flip issues). * Add more mass to IP to get lower frequency. * Adjust all GAS filters to near mid-range (using keystone mass for F0 as much as possible, and FR+LVDT for SF and BF). ==== Vacation/Etc Info ==== * Mark: 12/24 - 1/4. * Hirata-san: 12/24 - 1/4. * Fabian: 12/31 - 1/4 * Enzo: 12/31 - 1/4. * Mark and Enzo: KAGRA International Workshop in Perugia, 2/14-16. * Terrence: back at Kamioka from 1/7. |
==== Vacation/Travel Info ==== * Enzo at JPS then final vacation, 3/13-29 * Terrence's last day, 3/29. |
Scraps of text for incorporation in the VIS Meeting Minutes
KAGRA/Subgroups/VIS/MeetingNAOJ
Type B (Mark)
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.
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.
- Work on Type B paper.
- Tidy up.
- Throw out foil and other garbage.
- Gather and clean tools.
- Gather and organize unused parts and fasteners.
- Pull out unused cables in cable tray near SR3.
- Return all unused cables to tent.
- Tidy up cables in rear of SR2 rack.
Vacation/Travel Info
- Enzo at JPS then final vacation, 3/13-29
- Terrence's last day, 3/29.