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Revision 368 as of 2019-01-18 13:23:52
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==== Report for week of 12/17 ==== ==== Report for week of 1/14 ====
 * Etc
  * Hirata-san ordered three 41 mm spanners for adjusting the jacks under the top of the tanks.
  * Mirapro installed bellows on the -Y side of BS and the +Y side of SR2.
  * Simon got us an LED, a 2D QPD stage and a second 300x400 mm breadboard, which should be enough to do the SRM TILT OL. He's working on a few more items needed for the LEN OL.
  * Terada-san and Uchiyama-san placed height markers on the SR tank frames showing the BS height and the desired SR heights allowing for 1/300 gradient: SR2 BS+17 mm, SR3 BS+56 mm, and SRM BS+70 mm.
  * Terrence and Mark reworked the Type B Guardian code to simplify future maintenance, so that the scripts `VIS_BS.py` etc are now tiny stub files which call common code in `TYPEB.py`.
  * Mark, Terrence and Enzo updated all the Type B models and MEDM screens to add support for binary output to the stepper driver enable inputs, and Enzo ran cables from the front ends to the BIO adapters, and thence to the drivers. We tested the SRM setup but it doesn't yet work.
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  * 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.   * We installed the three new geophones originally prepared for SRM and then realized we'd made a serious mistake: the old wiring used adapters at both ends of the cable to compensate for the flipped preamps in the original geophones, and we forgot to take out the ones at the rack end. So two of the new ones appear to have been damaged and will have to be repaired. VIS has enough preamps to fix all the broken Type B geophones, but Type A will also need some more soon and there aren't enough in total, so we will have to repair them.
  * Hirata-san tried various things including turning the F0 FR carriage upside down to try to fix the jamming problem but it didn't seem to help. After advice from Takahashi-san and further debugging we discovered that we had a half-dead channel on the BS_GAS stepper driver, so we switched to a working channel, and that fixed things.
  * We recalibrated the F0 LVDT, this time measuring the height from the top down as we had been doing for the SRs. We also measured the range of the F0 FR in steps and millimeters and its effect on the keystone.
  * We tuned the IP for frequency and centered it in L, T and Y.
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  * 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. We still need to test this stepper.
  * 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 so we could inspect the payload, especially the OSEMs. We closed it back and covered with tape a small gap at the door.
  * Hirata-san checked the F0 yaw stepper and it worked.
  * (CHECK!!) Hirata-san checked the channels on the SRM stepper drivers and found they all worked. However the F0 FR still didn't move, so he tried turning the carriage upside down, and that fixed it. So between the BS and SRM there were two independent causes of the same problem.
  * Fabian surveyed the height of the SRM relative to Terada-san's reference with the GAS filters at nominal height and found it was 3.5 mm low. This is well within the range of the jacks, so we will raise the entire suspension to fix it.
  * Fabian inspected the optic. It seems OK for dust, but there is still some residue left from removing the FC. We may try some more dabbing with acetone.
 * SR2
  * Terrence and Enzo tested the third and last type of collimator (3500 mm) in the OL, but it had much too small a spot and dynamic range. We will standardize on 1.1 mm collimators for all OLs.
  * Fabian inspected the optic and found patterns that may be FC residue on both sides.
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  * 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 did f=1100 mm and will do f=3500 mm soon.
  * 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 day after installing the yaw stepper, we noticed the RM was touching the security structure but we were able to move it free by adjusting the cylinder with the spring and leaving the stepper motor in its nominal position. After this, for the other suspensions, we always checked the yaw of the payload immediately after installing the stepper.)
 * 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.
  * Fabian and Ohishi-san tried using the Top Gun to remove dust found earlier by Hirose-san. The AR side came clean but the HR did not improve. Fabian wiped the security structure and LBB with Vectra10 wipes and ethanol.
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==== Plan for week of 1/21 ====
 * Mark in Australia.
 *
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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.

==== Plan for week of 12/24 ====
 * Mark and Hirata-san on holidays, Enzo at Mitaka, Fabian.

==== 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).
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 * Mark: 12/24 - 1/4.
 * Hirata-san: 12/24 - 1/4.
 * Fabian: 12/31 - 1/4
 * Enzo: 12/31 - 1/4.
 * Hirata-san at Mitaka Thu 1/31, Fri 2/1.
 * Enzo at Mitaka Fri 2/8.
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 * Terrence: back at Kamioka from 1/7.  * Terrence at Kamioka till 3/29.

Scraps of text for incorporation in the VIS Meeting Minutes

KAGRA/Subgroups/VIS/MeetingNAOJ

Type B (Mark)

Report for week of 1/14

  • Etc
    • Hirata-san ordered three 41 mm spanners for adjusting the jacks under the top of the tanks.
    • Mirapro installed bellows on the -Y side of BS and the +Y side of SR2.
    • Simon got us an LED, a 2D QPD stage and a second 300x400 mm breadboard, which should be enough to do the SRM TILT OL. He's working on a few more items needed for the LEN OL.
    • Terada-san and Uchiyama-san placed height markers on the SR tank frames showing the BS height and the desired SR heights allowing for 1/300 gradient: SR2 BS+17 mm, SR3 BS+56 mm, and SRM BS+70 mm.
    • Terrence and Mark reworked the Type B Guardian code to simplify future maintenance, so that the scripts VIS_BS.py etc are now tiny stub files which call common code in TYPEB.py.

    • Mark, Terrence and Enzo updated all the Type B models and MEDM screens to add support for binary output to the stepper driver enable inputs, and Enzo ran cables from the front ends to the BIO adapters, and thence to the drivers. We tested the SRM setup but it doesn't yet work.
  • BS
    • We installed the three new geophones originally prepared for SRM and then realized we'd made a serious mistake: the old wiring used adapters at both ends of the cable to compensate for the flipped preamps in the original geophones, and we forgot to take out the ones at the rack end. So two of the new ones appear to have been damaged and will have to be repaired. VIS has enough preamps to fix all the broken Type B geophones, but Type A will also need some more soon and there aren't enough in total, so we will have to repair them.
    • Hirata-san tried various things including turning the F0 FR carriage upside down to try to fix the jamming problem but it didn't seem to help. After advice from Takahashi-san and further debugging we discovered that we had a half-dead channel on the BS_GAS stepper driver, so we switched to a working channel, and that fixed things.
    • We recalibrated the F0 LVDT, this time measuring the height from the top down as we had been doing for the SRs. We also measured the range of the F0 FR in steps and millimeters and its effect on the keystone.
    • We tuned the IP for frequency and centered it in L, T and Y.
  • SRM
    • Hirata-san checked the F0 yaw stepper and it worked.
    • (CHECK!!) Hirata-san checked the channels on the SRM stepper drivers and found they all worked. However the F0 FR still didn't move, so he tried turning the carriage upside down, and that fixed it. So between the BS and SRM there were two independent causes of the same problem.
    • Fabian surveyed the height of the SRM relative to Terada-san's reference with the GAS filters at nominal height and found it was 3.5 mm low. This is well within the range of the jacks, so we will raise the entire suspension to fix it.
    • Fabian inspected the optic. It seems OK for dust, but there is still some residue left from removing the FC. We may try some more dabbing with acetone.
  • SR2
    • Terrence and Enzo tested the third and last type of collimator (3500 mm) in the OL, but it had much too small a spot and dynamic range. We will standardize on 1.1 mm collimators for all OLs.
    • Fabian inspected the optic and found patterns that may be FC residue on both sides.
  • SR3
    • Fabian and Ohishi-san tried using the Top Gun to remove dust found earlier by Hirose-san. The AR side came clean but the HR did not improve. Fabian wiped the security structure and LBB with Vectra10 wipes and ethanol.

Plan for week of 1/21

  • Mark in Australia.

To-Do Lists, Schedule

Vacation/Etc Info

  • Hirata-san at Mitaka Thu 1/31, Fri 2/1.
  • Enzo at Mitaka Fri 2/8.
  • Mark and Enzo: KAGRA International Workshop in Perugia, 2/14-16.
  • Terrence at Kamioka till 3/29.

KAGRA/Subgroups/VIS/TypeB/Minutes (last edited 2022-06-24 12:23:36 by fabian.arellano)