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. We got 78 mHz.
• 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.

Report for week of 1/21

BS (top priority)

• Last Friday: We tuned the IP to have a lower frequency. At the begginig we measured 78mHz.
• Last Friday: With Lucia, we centered the IP and diagonalized the IP. After this process we measured a resonant frequency of 40mHz. We closed the position control loop for the IP.
• We checked during the weekend and the suspension was not in a healthy state. We checked the IM horizontal OSEM coil driver, and there were some cables in the wrong connectors. (Test in instead of ...)
• The commissioning team steered the BS IM to reach the Y-end and then Terrence centered the oplev with this orientation.
• Fujii-san and Enzo fixed old BS geophones by replacing the Preamp.
• We replaced the Geophones for the recently fixed ones.
• Hirata-san and Fabian secured trim masses to the keystone.
• We installed GAS Filters and IM control loops.

SR3 (priority 2)

• Fabian measured the optic height and we raised suspension on jacks (180 deg).
• Terrence reinstalled OL LED, replaced the collimator and relaigned the OL.
• We removed tape, writing etc on PI and PI items.
• We calibrated the F0 FR against the readout of the F0 LVDT. We removed the trim masses (110 g). Then we moved the F0 keystone by 1.3mm downwards.
• Fabian and Terrence centered the IP by using the Horizontal stepper motors.
• We diagonalized the IP actuation matrix. We closed the position control loop for the IP.
• We installed GAS Filters and IM control loops.

SR2

• Fabian measured the optic height and we raised suspension on jacks (180 deg).
• We removed tape, writing etc on PI and PI items.
• We secured the trim masses on the keystone.
• We centered the IP by using the Horizontal stepper motors.
• We diagonalized the IP actuation matrix. We closed the position control loop for the IP.
• We installed GAS Filters and IM control loops.

SRM (low priority)

• Hirose-san, Hirata-san and Fujji-san fixed the RM to the SS and removed the SRM for cleaning.

Postponed

• Raise suspension 3.5 mm on jacks.
• Check/improve payload alignment and IM OSEMs. Recheck optic pitch with OL as needed.\
• Adjust F0 keystone trim to give desired height and secure weights in place.
• Install geophones and arc weights.
• Center and tune IP.
• Hook LBB and add just enough ballast to have it bouncing.
• Wipe inside tank with Vectra-Alpha wipes and IPA.
• Set up TILT OL.