We moved the green iLIGO cleanroom from the HAM6 Laser Bay so that we could use it on the E Module at BSC8. I also worked on the cleanroom curtains.
This morning, Bubba and I moved three optic table enclosures from the LEA to the LVEA. One went to the HAM6 Laser Bay and two will be craned over into the West Bay for dis-assembly and storage since they are destined for LIGO India. This afternoon, Bubba fired up Big Red and moved the BSC ISI from Y-mid to the LEA.
Attached are plots of dust counts > .5 microns in particles per cubic foot.
The bug has been fixed, so I've reinstalled new gds tools for Ubuntu workstations. Mac OS X to follow in the morning. See note from earlier today describing changes.
Something is causing the iLIGO HAM1 Optical Table to be too low. First I measured the weights of the masses I'm using for the payload. A drawing error has me 11.254lbs heavy; I don't think this is enough to make a large effect. D080001 & 2, HAM Trim Mass Large & Small have their weights noted in lbs; looks to me they should have been Kg. So D080001 is noted to be 1.14lb, I measured 1.106kg; D080002 is noted to be 0.26lbs, I measured 0.25kg. I'll put redlines in the DCC. The Spacer D1200530 (between Support Tubes and Support Table) measured as drawn as I remember Mitchell confirming when we received these. I measured the Gap between the two Leg Elements (large masses in the isolation stack) in a few places to measure the compressed height of the Spring. This value is 1.86+-0.01". I did not measure an uncompressed Spring. T1000310 (PeterF's HAM1 Isolation Stack doc) notes a 2.03" tall Spring with 0.14" of compression. So about 3/4mm more compression (still early days too) x 3 for the three layers of Springs in the system. So, this would put us 2.5mm low...OK not enough there. Sam Barnum of MIT reports to me the compressed Spring height in the model (used to determine the Spacer height?) is 1.93" putting us 5.25mm (over 3 layers) lower than expected.... So I don't see enough from these listed issues to get us to 15mm, maybe 6mm low... Other possibilities are the leg elements and Optical Table are heavier than modeled...maybe I can put some numbers on that soon.
JimW, HugoP,
We recently huddle-tested the T240s received in LLO's shipment #4386. We took power specra that look fine. We also checked the pressure readouts which appeared surprisingly low: ~40kPa instead of the usual ~100kPa.
We investigated this issue and found that it was caused by a model discrepancy at X1, which does not match what is installed at ETMY and ITMY (see attached screenshots of the models: X1, ETMY, ITMY).
Pressure signal processing at X1: Pressure_Displayed
Pressure signal processing at ETMY/ITMY: Pressure_Displayed
If we reverse the processing applied at X1, and then apply the one of ETMY/ITMY we then obtain:
( 40kPa / 2.879e-3 * 5.065e-3) + 30.625 = 101 kPa
... Which is what we expected in the first place. The four T240 pods received in shipment #4386 were huddle-tested OK at recption. Results are available under the seismic SVN.
Other measurements performed during the investigation, at X1:
-We read 0 kPa when nothing is plugged into the T240 interface
-We read ~40 kPa with the T240s are plugged in
-We measured 8.36V at the T240 interface (D1002696) "to-Anti-Alias" output
-The power supplied to the T240 interface is:
-17.96V
+17.75V
Today marked the official end of the 1-Arm Test (laser powered down at EY [laser safe there now], venting of Y-Beam Manifold, etc.)
MC3 has all 6 top BOSEMs plugged in and backed off in prep for new OLVs and gain settings. As well, we've attempted to fix the side BOSEM flag cross coupling - we indeed found the flag to be mounted quite crocked and have straightened it. TFs will tell us if the cross-coupling is alleviated.
While rechecking the open light voltage offsets on the MC3 INMONs, I noticed that the T2 BOSEM gain was set to 1.405 (likely instead of 1.045). Possibly this is what was causing heart ache during the testing phase immediately after the build across the street in the staging building on this sus. The gain should now be set to 1.049 since I remeasured with the sus on the production cables/electronics. Attached is a snapshot of the inmon setting before my work today.
And the new settings from today snapshotted below - mostly small number tweeks except for the T2 gain noted above.
The burt restore file to be used should be the cds auto one at:
/ligo/cds/lho/h1/burt/2012/09/18/17:00/h1susmc3epics.snap
The user models on h1sush2b (IM) and h1susauxh34 were found to be stopped. Also the IOP models on these front ends had a large timing offset, consistent with a timing/Dolphin error.
I restarted the models on both of these front ends with no problems.
All brushing was completed this morning. First vacuum was completed this afternoon and wipe-down got started.
There was a transverse to yaw cross coupling noted in the TFs for H1-PRM (orange trace). To isolate the problem we moved the side BOSEM to the other side of the suspension and re-tested. With the BOSEM on the opposite side, the cross coupling disappeared (black trace). Before moving the BOSEM back to its correct side position, I found the magnet/flag base to be misaligned. This was corrected and the BOSEM was re-centered to 50% light. Subsequent testing shows the cross coupling has been removed (purple trace). H1-MC3 and H1-PR2 also show the same cross coupling. We will check the side magnet/flag base alignment on these two suspensions and re-align as necessary.
[Stuart A, Jeff K and Jeff B] Adjustment of the PRM (HSTS) side flag mounts rectified the Y to T cross coupling observed in previous measurements. But something else appears to have cropped up. The plots below (allhstss_2012-09-19_0940_All_Phase1b_PRMs_ALL_ZOOMED_TFs.pdf) show a comparison between the latest two complete data sets of un-damped M1-M1 TFs, with the most recent being the orange trace. It can be seen that these recent TFs exhibit signs off:- - Roll (slide 4) looks to show stronger vertical mode coupling at ~0.85Hz - Pitch (slide 5) looks to show stronger vertical mode coupling at ~0.85Hz Most likely, these are sensor-related cross couplings -- as in the usual imperfect subtraction of common mode signal (Vertical) in the differential signals (Roll and Pitch). But they were not so apparent in the 2012−09−06_2000 data, and we wish to be sure that they are not related to the re-alignment carried out on PRM to rectify the Y to T cross coupling. To demonstrate the significane of these Pitch and Roll cross couplings, we provide a plot showing similar couplings for ALL HSTSs from both sites (allhstss_2012-09-19_1040_All_Phase1b_HSTSs_ALL_ZOOMED_TFs.pdf). This demonstrates that compared to other HSTSs the feature in pitch (again the orange trace) is less of a concern. However, the feature in roll could be considered egregious. It should be noted that the most recent PRM TFs were taken during the middle of an active day. Therefore, the next data will be taken at a quieter time, when the common mode (Vertical) signal is reduced (or by just turning on the Vertical damping loops while taking the Pitch and Roll measurements with loops open). All plots and scripts have been committed to the sus SVN as of this entry.
Christina and Karen will do a gross cleaning of the uncovered Test Stand and vicinity this morning. That should give us some idea of how many cleanings will be required to get things into reasonable shape to receive the cartridge.
Phase 1 Cleaning of the HAM cleanroom is complete and signage posted.
There appears to be a favorable slope change starting ~ Aug 8 (65 days on this log/log plot) Browsing the aLOG I find that near that time there were ring heater operations, and one week prior to this Kyle disconnected a small turbo pumping the BSC6 annulus. I don't think either of these explain the slope change. I also looked at the big ion pump voltages during this period - there were no step changes anywhere near this time.
GV18 was cycled on August 7-8 -Rai might have been making RGA measurements?
John, You are correct I was making measuremants and moving the gate valve on both August 7 and 8. It seems that the slope became 1/t after the measurements. It is not easy to understand this. The first thought would have been a leak in the valve between the RGA and the chamber with a poor vacuum in the RGA. This is not the case as the 2 liter/sec ion pump was holding the pressure in the RGA volume below that in the chamber. Another possibility is that the annulus system was leaking but you rule this out from Kyle's measurements. I am stumped. RW
Kyle decoupled the annulus turbo pump on July 31 - probably not this.
A signal we do not yet have is the BSC 6 annulus ion pump current as this chamber and it's pump were brought from the mid station. - I'll ask Dave about this.
Kyle recalls that he disconnected the annulus turbo pump for noise reasons at the request of Robert rather than for vacuum reasons. Some days later he was surprised to find that the annulus ion pump had "come on scale" as if the pressure had fallen in the annulus space to the point where the ion pump could start.
This suggests that there may be an inner oring leak from the annulus to the BSC6 chamber which might explain the slope change. Once the annulus ion pump began pumping, this gas load was removed from the chamber.
Richard has our electrician working at connecting up our new annulus ion pumps to the CDS system so that in future we will be able to trend these signals. At the time we did not assign any priority to this work.
A new version of gds software has been installed for Ubuntu and Mac OS X workstations. The notable differences appear in foton and diaggui. Widgets for displaying channel names have been made much wider, forcing the layout of several screens to be changed. Diaggui measurement tab now shows 2 columns of channels instead of 3. Diaggui excitation tab has two channel name widgets for each excitation, the wider length required these to be put on separate lines. The plot options panel on the result tab is also wider to accomodate long names - this affects foton as well. Since the plot options panel is wider, there's less room for the actual plot, but the option panel can be detached so it "floats" which should allow plenty of room for the plot. The Export popup dialog in diaggui also has channel name fields that have been made wider, and there's now an option to add a header to the ASCII export file. The header contains information to allow identification of the source of the data. Complaints should be addressed to me or filed with bugzilla.
I have reverted GDS tools to the previous version, 2.16.3 due to a bug discovered by Hugo.
