At midnight this morning the main control room NFS server suffered a scsi error and the /ligo file system went into read-only mode. This means you cannot modify or create files on the /ligo file system, which includes user home directories and the cds wiki pages. This is a known problem with this type of integrated computer and file server, and the only resource is to power cycle the machine, which cannot be performed remotely.

The immediate problem this causes is the hourly autoburt backups are not recording. I can reroute those to the h1boot file system temporarily until I can get to the site to reboot the server.

The problem occured at 4 mins past midnight, Sat 9 Feb.

Vincent was keen to test IPC between his new BSC2 ISI model and the BS SUS model, but the latter hadn't been created so I waded in and created it. I adapted the existing BSTST model and then compared it at the end with the L1 version - they were gratifyingly similar, except for the IPC stuff, which only exists in the H1 version so far. I got it running and updated the sitemap to point to it. I installed projection matrices, filters, and default gains and offsets, and created a safe.snap. 

Along the way I discovered that the SUS_CUST_BSFM_ADC_MONITOR.adl screen had been hardwired to L1, so I fixed that.

I noticed a few anomalies that need further debugging:

* The output fields on the SUS_CUST_BSFM_OVERVIEW.adl screen between the USER DACKILL and the IOP DACKILL (H1:FEC-31_DAC_OUTPUT_2_4 etc) are white. There's also whiteness in the H1CDSOVERVIEW.adl screen.

* The M2LR OSEM is showing a non-zero, fluctuating value (≈±2500 counts) despite having no OSEM connected.

* There's red in the Dolphin IPC bit on the H1CDSOVERVIEW.adl screen.

Apart from all of that(!), very possibly when the physical suspension is connected up it will damp.

[Paul, Kiwamu, Keita, Dick, Rodica]

Today we measured the mode cleaner cavity length by modulating the EOM at 45 MHz and doing a sweep around this frequency. We measured the spectrum using an HP 43968 Spectrum Analyzer. The maximum source power was 19 dBm from a Mini-Circuits RF amplifyier with gain 19 dB. The bandwidth for the highest zoom on the peak was 300 Hz.

The frequency of the dip in the middle should correspond to the 5th FSR away from the carrier resonance. The calculated length is 9.09918 MHz +/-  100 Hz, only 291 Hz away from the design value of 9,099,471 Hz. This is equivalent to 1.05 mm difference from the design length.

We tried a full sweep over one FSR but we realized that the modulation away from resonance would be too small to give us any useful results, so we focused on the 45 MHz resonant peak. Attached is a plot of the data over a full FSR, that also shows a peak corresponding to the non-resonant polarization, and few other peaks possibly due to higer order modes.

Similar measurements at LLO are described in alog 4702.

Attached are plots of dust counts > .3 microns and > .5 microns in particles per cubic foot requested from 5 PM Feb. 7 to 5 PM Feb 8. Also attached are plots of the modes to show when they were running/acquiring data.

Data was taken from h1nds1.
1440.0 minutes of trend displayed

[Rodica, Kiwamu, Dick, Michael R., Keita, Paul]

Last night and today we finally managed to get what looked like a good measurement of the IMC pole response. Here is a brief description of the measurement setup:

Swept sine signal applied directly from the SRS785 to the AOM driver box inside the PSL. Frequency range was 1kHz to 100kHz, signal amplitude was 400mV pkpk. 1000 intergration cycles, and 101.56ms integration time. Measurement was a transfer function from the DCPD on the PSL installed recently (PDA55) to the DCPD on the IOT2L table (DET100A). ~200mW injected to modecleaner.

The PDA55 on the PSL table didn't give us an observable signal from the amplitude modulation previously when we tried on Wednesday. Rodica checked the Thorlabs recommendation for best linear performance, which states that the maximum intensity should be less than 10mW/cm^2. Even with a very low beam power we may have been exceeding this value due to the very small beam size. The PD was therefore moved to have a larger incident beam size.

We were struggling to get a decent signal on the SRS785 until Kiwamu suggested reducing the light power reaching the PDs to less than 1V. Once we brought the power down to less than 600mV, we were able to see a decent signals on the SRS785 and began taking TFs. 

The first attached transfer function is directly from the PSL PD to the IOT2L PD. In the event that the response of both PDs is linear, this should just give the cavity response. However, we noticed that the phase dropped below -90deg on the TF, indicating the presence of another pole - likely that of one of the PDs. We therefore took a TF from the PSL PD to the IOT2L PD, with the IOT2L PD repositioned in the IMC REFL path and the cavity misaligned (as Giacomo did previously). This TF is the second attached plot, and shows the pole of the IOT2L PD. Finally, we then divided the first transfer function by the second to eliminate the different PD response, leaving us just with the cavity response. This transfer function, along with a fit, is shown in the third attached plot.

For now, I just fitted the phase of the pole measurement, which gave the result 8812.36 Hz for the cavity pole. I'll try a complex data fitting routine soon and post the result.

Following the install of OneStop cards in the IO Chassis for h1seib2 and h1susauxb123 I made the first release of the IOP models for these front ends.

h1iopseib2 and h1iopsusauxb123 models were started this morning.

I went through all the H1 IOP models this afternoon to clean them up, bring the comments up to date and add the SVN keywords $HeadURL$ and $Id$.

I then added the propset for these keywords and submitted to svn.

I'll schedule a rebuild and restart of all IOP models at some future maintenance time.

h1susauxh34 received a new OneStop card but is still showing a power supply problem.

I also cleaned up the LHO CDS Overview medm screen to remove systems we are not immediately installing (e.g. SUS ITMX) to remove misleading white blocks.

• IO team worked on MC cavity pole measurements
• Apollo worked on the transition of install infrastructure from BSC 1 to BSC 2 and drilled for cable tray supports along the Y beam manifold.
• Eric and others worked on HEPI actuators at BSC 3
• Michael R and Joe D inhabited the H2 PSL enclosure for much of the day, prepping for PCal assembly
• Richard -- EX access controls
• Hugo, Mark and Vincent working on SEI and SUS in the afternoon.
• No surprising alarms
• No work permits signed by ops today
• Second-Saturday tour tomorrow, RIck and Gregorio
• Note other entries about today's activities below
• Cyrus restored joystick control of the roof and LVEA cams; this disables the Web controls

Dust monitor 4  in the beam splitter test stand clean room was of interest today because of drilling for cable trays along the Y beam manifold.  Signals from this monitor were quiet throughout the drilling, with only occasional 3um counts of 10 or 20.  There have been several higher count episodes (100-200) over the last 1.5 hr while someone has been working on the suspension.

That is half of the L4Cs have been leveled.  We got the East side done today and will work on the West side corners Monday.  The HEPI remains unlocked--mind the signs please.

Attached are plots of dust counts > .3 microns and > .5 microns in particles per cubic foot requested from 5 PM Feb. 6 to 5 PM Feb 7. Also attached are plots of the modes to show when they were running/acquiring data.

Data was taken from h1nds1.
1440 seconds worth of data was unavailable on this server
1440.0 minutes of trend displayed

Betsy (sadly logged in as Robert)

Today, we finished adjusting the roll, pitch, and z DOFs of the glass PRM.  The center of the optic is sitting at 158.75mm above the table surface (if it had the 19.1mm spacer under it).  The nominal is 158.8 +/- 1mm.

Travis adjusted the top stage BOSEMs to center in x,y,z and Mark is on deck to run TFs.

We;ll refit the lower stage OSEMs next week.

Found BSC5 dome annulus is leaking badly -> Will spray new CF joints next week

Vincent told me that H1 TMSY was ringing up when the damping was on. BIO was working.

Eventually I found that I had to turn down the damping gain of all rotational modes by half, plus turn off ELF10 filters in the coil outputs, to get going stably. Since there is zero reason to go aggressive under the air, I'll leave them like that for now.

H1:SUS-TMSY_M1_DAMP_R_GAIN is -10 instead of -20.

H1:SUS-TMSY_M1_DAMP_P_GAIN is -5 instead of -10.

H1:SUS-TMSY_M1_DAMP_Y_GAIN is -5 instead of -10.

All ELF10 filters are disabled instead of enabled.

My guess is that somebody decided to go aggressive under the vacuum a long time ago, and now, in the air, OSEM positions are different and that makes coupling between DOFs different, causing oscillations.

Viton pads are usually set under the balancing masses of the HAM-ISIs in order to damp resonances at high frequencies (above 100Hz).

The SEI team would like to asses the improvements that the Viton Pads help achieving. To do so, we decided to have viton pads under the balancing masses of the ISIs of LLO's IMC, and to try without those pads here at LHO.

Transfer functions were measured ovenight on LHO HAM3-ISI. We compared those transfer functions with the ones measured at LLO under an equivalent state:

• ISI is in vacuum
• MC2/PR2 are installed and damped
• TMDs are intalled on the ISI
• HEPI is locked

Comparative plots are attached.

I acknowledged the following alarms Friday morning:

• HVE-LY:CP1_LT100 (minor alarm, value=83.9 at 23:36:25 on 2/7)
• H0:PEM-LVEA_DSTl_3
• H1:PSL-ENV_DIODERM_TEMP_DEGF major (exceeding 70F between 1:00 and 2:00 on 2/8)
• H1CDS_IOP_SUS_WATCHDOG ITMY OSEM6 (minor, value=500, 18:11:29 on 2/7)

All of these cleared when acknowledged except the IOP which remains yellow.

The Apollo crew removed the ISI from BSC 10 and placed it on the north side of the termination slab, wraped, bagged and sealed. We chose to stand down on the ICC for now, instead we relocated the clean rooms that were over HAM 4 and BSC 1 and began disassembly of the E module and work platform around BSC 1 to be relocated to BSC 2.

At approx 08:10 this morning the network to the EX FMCS system and the wall camera was disrupted. Upon investigation we found that the ethernet cable in the VEA rack was disconnected. This cable had an extender and a 6 feet additional ethernet cable before it plugged into the Foundry switch. The connection at the extender was disconnected. We found that the extender was not needed any more and plugged the long haul cable directly into the switch.

[Hugo, Rodica, Paul]

Today we were finding it impossible to lock the IMC again. When we looked at the SUS-MC2-M3_LOCK_L_OUT_DQ channel, the signal appeared to be always railing (on both sides). We have seen this before at times, due to very noisy seismic states (see e.g. entry 5145). However, even with what we expected to be a quiet siesmic and ISI state, we still found this signal railing at ±40,000 counts, making it impossible to lock using the length path. In the end, Hugo realised that when the model was recently updated, the limit on the MC2 M3 lock filters had reverted to its initial old value of 40k counts. Apparently at some point this was increased to 400k counts, but not saved in a safe.snap file. Hugo increased the limit back to this value and the mode cleaner began locking again.

We should update the safe.snap file so that any further reboots revert to the 400k counts limit.