Check ResourceSpace for the photo collection of last week's cartridge move. This is the one-arm test cartridge that came out of BSC 8 early in October 2012. Once on the test stand in October, the ISI's folding mirror suspension was transferred to the neighboring BSC 2 ISI and re-christened as the beam splitter suspension while the quad's position was adjusted on the BSC 1 ISI. SUS locking photos courtesy of Jeff Bartlett.
Gathering closed loop transfer functions on H1 SUSITMY, started ~1:30p ET / 10:30a PT, will cease (regardless) at 3:00p ET / 12:00p PT.
Transfer functions complete.
[Dick / Kiwamu]
We found an RF cable whose signal level depends on the angle of one of the cable end. This is not good. I consulted with Filiberto on this issue and we decided to leave it to the electricians who are coming in the next week from Caltech. Or if the cable turns out to be necessary soon, we can just swap or fix it by ourselves.
--- the Cable
place: remote rack C4
connection between : U42-1 and U9-1
description:71 MHz for a VCO
length: ~ 2 m
type: N male / N male
--- Symptoms
* The RF power dropped from 11 dBm to -8 dBm suddenly while doing nothing
* Applying tension at the cable end (the U9-1 side) introduces variation in the RF power by ~15 db or so.
--- Assessment
At the beginning we thought that the power variation was due to the connector which is a part of the U9 circuit box (i.e. the channel 1 output of an RF distribution amplifier D100024/S1000595). We pulled out the circuit box and brought it to the EE shop to do a further investigation. We didn't find anything wrong. So we put the box back to the rack and it seems working fine.
Eventually we located the issue and confirmed that it was in the RF cable and not in the box. Currently everything is back to place.
I have just removed the cable and cut it so that noboday can accidentally use it.
For the 35W beam
The 59 Hz chiller pumps at EY produce turbulence in the water lines that results in a peak at about 9 Hz in seismic spectra at Y-end. This peak creates problems e.g. for ISI. We have been planning to install a variable frequency drive (VFD) at EY so that we could reduce the water flow, in hopes of reducing the turbulence. The VFD was installed at EY this week and I ran some tests at various frequencies (pump speeds). Figure 1 shows that the peak is nearly at background with the VFD set to 30 Hz, instead of the nominal 60 Hz. 40 Hz is also pretty good so we decided to run at 35 Hz from now on. We believe that the cold water flow rate is down by less than a factor of 2 and that this should be sufficient for our needs. We will find out for sure when it gets hot next summer. We also now have VFD at EX and the corner station so we can adjust these as needed.
End Y is, as of now, in a seismic condition pretty similar to what we plan for aLIGO science mode. There are still a few pumps making sharp lines, but the broad band should be pretty close, especially when people are not out at End Y. To test the pointing of the seismic array, I placed a shaker on the floor at two locations Wed. night, running at 12 Hz. The times were:
Nov. 15 2012 0:54:54 UTC to 2:20:40 UTC (last ten minutes were the most quiet) and
Nov. 15 2012 2:29:40 UTC to 3:00:00 UTC (first fifteen minutes were the most quiet).
Robert S., Richard M., John W.
Attached are plots of dust counts > .3 microns and > .5 microns in particles per cubic foot from approximately 6 PM Nov. 15 to 6 PM Nov. 16. Also attached are plots of the modes to show when they were running/acquiring data. There is still an occasional calibrate failure alarm on the dust monitor in the OSB optics lab. Dust monitor 4 in the LVEA was turned back on.
[Michael Rodruck, Alberto]
Today we finished setting up the optical path to couple the PSL reference cavity tranmsitted beam into the ALS fiber. After we mode matched the beam to the fiber launcher, we aligned it into the fiber by using the OzOptics auxiliary fiber laser. We coupled 3.0mW into the fiber, out of the 5mW coming from the reference cavity: a 60% matching. It didn't look like this could be imrpoved by much.
Both ALS setups on the PSL table are now almost complete. The only work left to complete is the replacement of the Faraday's mount on the ISCT1 pick-off path: the mount is currently under construction at the machien shop.
Details on the optical alyotu of the fiber setup are in LIGO-T1200471-v7.
One hypothesis for the source of excess vibration noise on the PSL table from the crystal chiller circuit (here) is that the ~2 mm aperture in the quick-connect hose fittings on the 5/8” ID hoses causes a turbulent jet of water that, especially if bubbles are present, modulates the flow of water. Figure 1, lower plot, shows that a quick-connect is about two orders of magnitude more noisy than a barbed barrel connector for the 10 - 15 l/m flow through the crystal circuit of the crystal chiller. Figure 2 has a photograph of the setup.
To see if the noise from the quick connect might be loud enough to explain the noise from the whole circuit, we clamped the quick connect setup used for the above measurement to the outside manifold of the crystal box (setup photo shown in Figure 2). The upper plot in Figure 1 compares the nominal noise to the noise from this setup. The peaks produced in this way are relatively large but don’t match the peak from nominal flow through the box. However, the momentum transfer to the table for our test is much different than in the actual setup.
I think the results are suggestive enough that it would be worth an experiment where we replace the two quick connects at the crystal box manifold with barbed connectors. To further improve the flow, we suggest that we use the capped threaded holes for this in order to make one less 90 degree turn. Figure 2 also has a photograph illustrating the proposed modification.
Robert S., Michael R., Rick S.
WP#3568
Following the wiring of the new BSC6 75l/s Ion Pump, I created a new database file for the h0veey VME IOC called HVE-EY:75IPBSC6.db. This is essentially a copy of the existing BSC10 database, with BSC10 replaced by BSC6 and 411 replace with 425.
At 13:31 we restarted h0veey with the new database, all went well. I also changed:
I also fixed the MEDM to MEDM links for the vacuum screens on the control room machines.
Unifirst arrived with floor mats. A viewport was installed in the septum between HAM 1 and 2. Michael R. transitioned the LVEA to laser hazard for MC locking work. Michael R. transitioned the LVEA to laser safe. Richard and Dave added the ion pump on BSC6 to the control system. Michael R. and Alberto worked on aligning the PSL ALS optics. Dale lead a tour through the control room.
This afternoon Andres and I removed the H1-Pr3 and H1-PRM HAM suspensions from their storage containers and placed them on the chamber-side optics table in the LVEA. No problems were encountered during the move.
I needed a little hardware for the dial indicators for BSC1 and I had to rob from BSC6. The two western DI trees are no longer engaged but the East side has three axis monitoring still on both corners. And of course there are still the HEPI IPS. Before disconnecting the west side, I recorded the indicators and comparing to my last recordings, they are still reading valid. I see a coherent rotation of about 0.1mrad clockwise wrt the readings I logged on 30 Aug. The vertical readings are unchanged.
For new shells started after 12:03 PST, the default nds server has been changed to h1nds0.
Installation of last Custom Wedged Viewport VP2 to IO Septum (between HAM 1 & 2) completed with Apollo. Wedged VP orientation was with the thick part of wedge (scribe mark on flange) to 3:00 O,clock position so deflection is horizontal in nature. HAM1 can now be isolated as needed.
The IR beam was successfully aligned from the PSL to HAM2, through the IO periscope, off 2 steering mirrors, and through MC1 to HAM3. In HAM3, we discovered that MC2 has FC, which precludes bouncing a beam back to HAM2. We aligned the beam to MC2, explored some options for continuing to work, and then called it for tonight.
Attached are plots of dust counts > .3 microns and > .5 microns in particles per cubic foot from approximately 6 PM Nov. 14 to 6 PM Nov. 15. Also attached are plots of the modes to show when they were running/acquiring data. The sensor may be failing in the dust monitor in the optics lab (H0:PEM-LAB_DST1). The calibrate failure alarm is being raised momentarily (status of 1 in attached plot). Dust monitor 4 in the LVEA may have been turned off after the cartridge install. It was in the clean room over the test stand farthest from the Y manifold.
I continued the build of the SUS frontend for ITMY (h1susb123). Richard resolved the SFP timing issue this morning and the IOP model has been running all day. I built the h1susitmy model by copying the H2 model this afternoon but then found that the H1.ipc IPC file has exceeded the 64 Dolphin channels limit. It exceeded it some time ago when EY was copied over to H1. So I have put a halt on ITMY development until we can get this resolved. I have taken out the ITMY IPC channels from H1.ipc and stopped the h1susb123 models for now.
Noted that the computer time was about 4 minutes fast, investigated, found ntp had not been installed on h1dmt0. Installed the ntp package, configured, set the date, and started the ntp client.
John took the attached RGA scan of the Y-end station today using the iLIGO RGA (not Rai's hydrocarbon RGA)
Note -the pressure at PT 410 is currently 7e-9 torr.