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| ==== Report for week of 10/22 ==== ===== SRM ===== * We borrowed the TM HPCDs from SR2 and SR3 so that SRM had HPCDs for IM-H, IM-V and GAS. * Fabian adjusted the last two OSEMs (IM-H2 and H3). * We closed the BF and weighed the BF/... section. * Fabian and Hirata-san routed all the BF/... cables via the BF cap (except for the four TM OSEM cables, where we're still waiting for extensions). * We built up the assembly frame and security structure to the SF level and craned in the SF. * We installed the SF-BF rod and flying saucer. * Hirata-san collected a suitable CuBe spring and bracket parts from Type A. He ultrasonically cleaned the bracket and then installed the bracket and spring on the F0. * Enzo soldered some short and/or broken cables to make longer cables that we need urgently. He got in touch with Yamamoto-san to arrange bringing them to Toyama University and ultrasonically cleaning them. * We pulled out cables running to the OMMT area that were used for the old OSEM/geophone testing setup and started a new geophone testing setup in the SR3 area using the optical table from the SR2 assembly frame. * Hirose-san reported results from his astigmatism test on the second SRM small optic and metal mass. With the tight shims (1.0 mm thickness, as used for the installed SRM) there was substantial astigmatism, but with the next looser available size (1.5 mm), there was no astigmatism but the optic is held very poorly and rattles. Hirose-san is ordering some intermediate thicknesses and will make a recommendation. However he will almost certainly suggest that we change the shims on the hanging SRM, so we need to think about whether that is feasible. |
==== 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. |
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| ===== SR2 ===== * Akutsu-san collected the parts we will need for the SR2 OL so that Terrence can install it next week. * Hirata-san supervised the disassembly of the assembly frame. The pieces are now in the IMMT area, although we may need to move them again because they're a bit in the way. |
* 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. |
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| ==== Plan for week of 10/29 ==== * Mark, Enzo, Hirata-san, Fabian and Terrence at Kamioka Mon-Fri. ===== SR2 ===== * Set up OL. * Do a measurement of how much torque is required on the F0 keystone to move the system in yaw. (This will help Sato-san choose a suitable stepper driver for the new design.) * Possibly add more arc weights, to get below 0.1 Hz. ===== SRM ===== * Continue assembly. ==== 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)]] |
* 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 BIO Config 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 low-pass filter to get rid of it for now. |
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| ==== Vacation/Visitor Info ==== * Terrence: 10/29-11/2 at Kamioka. |
==== Plan for week of 3/18 ==== * Mark, Fabian, Terrence at Kamioka full week. * More OL stuff. * SRM OL setup. * Recalibration of all OLs per new procedure. * Improve mounting of BS OL RX breadboard. * Reinstall BS LEN OL. * SRM controls and Guardian. * Reset SRM yaw and continue monitoring yaw drift. * Length/pitch decoupling. * 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. |
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 BIO Config 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 low-pass 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 OL setup.
- Recalibration of all OLs per new procedure.
- Improve mounting of BS OL RX breadboard.
- Reinstall BS LEN OL.
- SRM controls and Guardian.
- Reset SRM yaw and continue monitoring yaw drift.
- Length/pitch decoupling.
- 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.