For the last several weeks we have been testing a rss feed of the alog.  It is now being moved to be a publicly exposed and advertised feature.

The feed is located at rss-feed.php.  If you are using a RSS aware browser you should be able to find the feed in whatever method your browser exports feeds.  For example in Firefox the 'Subscribe to this page...' entry of the bookmark menu becomes available.

This update is scheduled to be rolled out to the LLO logbook tonight.

END Y after 6 days of pumping. No change in trend - suggests this is not an air leak.

[Stuart A, Mark B, Jeff B, Vern S]

Whilst last visiting LHO I was able to quickly make some open-light and one dimensional responsivity measurements using three dirty AOSEMs and a test-jig kindly loaned from Mark. The test-jig has previously been used for characterising BOSEMs, and so had to be reconfigured to accommodate the smaller AOSEM coilformer. More importantly, rather than using the rectangular flag employed for the BOSEM, a ~1" long x ~2 mm diameter cylindrical flag was provided by Jeff B.

A UK production Satellite Box (D0901284) was connected up to the AOSEM under test using a dirty in-vacuum quadrapuss harness (D1000234). The Satellite Box was provided with it's required supply lines via a Satellite Box Testing Board (courtesy of Filiberto). For electronics set-up please see image 504 below. A DVM was used to read-out the amplified voltage signal via the diagnostics port (J4) on the Satellite Box (Pins 9 and 28). Note that, the production Satellite Boxes have a input gain of 242k V/A or 0.242 µA/V (double-ended).

Image 506 (below) shows the opto-mechanical set-up for the reconfigured test-jig, including the translation stages and flag assembly. For these tests, only the responsivity is sought, and therefore a one-dimensional characterisation along the sensitive axis is adequate.

When connected up to the Satellite Box, each of the AOSEMs had the following open-light differential voltage measurements:-

- Unit #1, open-light = 14.75 V (i.e. an open-light photo-current of ~61 µA). Corresponds to ~24k counts
- Unit #2, open-light = 10.14 V (i.e. an open-light photo-current of ~42 µA). Corresponds to ~17k counts
- Unit #3, open-light = 12.19 V (i.e. an open-light photo-current of ~50 µA). Corresponds to ~20k counts

Over a ~0.7 mm operating range, these AOSEMs were found to have the following responsivity (see plot below):-

- Unit #1, responsivity = 18784 V/m (i.e. 78 mA/m).
- Unit #2, responsivity = 13028 V/m (i.e. 54 mA/m).
- Unit #3, responsivity = 15721 V/m (i.e. 65 mA/m).

These responsivity results can be compared with the default value we have previously assumed of ~80 mA/m (see LLO aLog entry 2715).

To summarise, these measurements can be used to validate our assumption of using the AOSEM calibration factor of, 1/(80e-3 [A/m] * 240e3 [V/A] * (2^16)/40 [cts/V]) = 3.2e-8 [ct/m], is consistent for units with open-light counts above Jeff K's goal of 25k.

I have reorganized and added medm snapshot screens to the CDS web page (LIGO.ORG authenticated):

https://lhocds.ligo-wa.caltech.edu/screens/

Vacuum and FMCS detailed medm screens have been moved to their own web pages, the overview screens are shown on the main page

A H1 section has been added, it contains the H1 CDS OVERVIEW MEDM

The H2 IOP SUS/SEI watchdogs screen has been added to the H2 section

Yesterday Keita and I found that the output of the ALS PLL Phase-Frequency Discriminator unit was noisy and oscillating between its voltage rails.
We traced the problem back to a very noisy output signal from the frequency divider which provides the LO to the P-F Discriminator board.
Going up the chain, we found that the frequency divider unit was getting 0dBm instead of the nominal 13 dBm from the VCO unit. 

Apparently the VCO unit is not working properly. We removed it from the rack and took it to the corner station for inspection.
We are going to check it inside to find the cause of the mismatched power levels.

The problem of HAM front end startup corrupting the H1PSL data was tracked down to a switch configuration and was corrected.

The following front ends and models were created by porting the LLO running models to H1. 

All the models started with no problems except for h1susim (which has an undefined symbol).

All systems were added to H1 DAQ using the INI files generated from the models. The H1 frame size roughly tripled in size from 1MBps to 3MBps.

Laser current set to 1.5 amps.

IR output 1.125W (after the laser head), 50.0mW (after Faraday, we're using wave plate to intentionally dump some power), 10mW after PBS (another  attenuation, we can decrease this, or increase this up to 50mW)

With 10mW going to the PLL diode, we have about -3dBm beat note.

green output 22.9mW (right after the laser head), 17.5mW (after the first Faraday), 13.85 (after the second Faraday), 12mW (just before the bottom periscope mirror)

Retroreflection (measured after 10:90 splitter) 0.73mW, this means that the retroreflection is 7.3mW.

Apparent table efficiency is 7.3/12 = 61%.

Aluminum mirror reflectivity is probably not that good (95%-ish if they're good) (turns out that they're silver, not aluminum, coated, thanks Matt for pointing it out, and this means that the reflectivity of these is 98% or so rather than 95), and there are four such mirrors (TMS telescope mirrors), double path, meaning there are 8 reflections. This should amount to 0.98^8 = 85%-ish.

There is a splitter for QPD (5%? I don't remember), again double path, so if it's 5% splitter this removes 10%. 

0.85*0.9 = 77%-ish.

Helium spraying this afternoon has been inconclusive - intermittent response has been sufficient to keep us interested but we were not able to pinpoint any source. Maybe leakage through the annulus and orings.

We decided to try starting up the BSC10 RGA.

After finding and resurrecting the computer and controller we found that the controller would not power up. Retreived another unit from YMID, installed it, and found filament emission error on startup.

Documentation shows the last operation of this RGA was in 2008.

We will continue on Monday. I am starting to wonder if this can just be a very saturated system as we were vented for 3 months while the cartridge install was performed. For this period the iLIGO stack in BSC10 was exposed to the purge air.

Kyle,Gerardo,John

The ISI is sitting on Spacers (Between Stage0 & SEI Support Tubes)--D1101180 type 00 (2.830+-.005" tall).  The Spacers are bolted to the Support Tubes with one bolt at each end (torqued after ISI was landed and torqued).  The ISI is bolted to the Support Tubes sandwiching the Spacers.  The ISI has six bolts on the East (-Y) side and would nominally have 9 bolts on the West side.  This is due to the trisymmetric ISI blocking the middle three bolts on the East side with one Spring Support Post.  This ISI only has seven (7) bolts on the West Side rather than 9.  First, the ~3" tall spacer requires the use of a 5" bolt.  This length prevents the middle bolt in the run of 9 on the West side from being installed as it runs into the Corner1 Vertical Actuator.  HAM3 will also see this issue.  Further, it would appear the second hole in from the SW corner (+Y-X) of the Support Tube is stripped.  We will try to review our 12 & 13 year old records for this problem.  The Support Table was extracted by the In-Chamber Cleaning group and maybe they'll recall a missing bolt.  Otherwise, we did not wish to re-lift the ISI and remove the Spacer to inspect the hole.  So again, only 7 bolts on the West side--not standard.

I took over the afternoon shift for T-Vo (he had work at EY)

Afternoon Activities

• Alignment on ALS table (Thomas V)
• Leak checking at EY (Gerardo, Kyle)
• Purge air-related work (Ski)
• HAM-ISI work:  Added payload to Optics Table, Shipping Braces removed & ISI torqued down to Support Table (eric, greg, hugh, jim)

The PSL was shut down today to allow for work in and behind the racks (to avoid accidental power disconnections). That work has been completed and the PSL has been brought back up.

The ILS would not lock the lasers, but once the phase of the ILS LO was set back to 42 degrees (from 242 degrees) it locked up immediately. Had similar issues with the PMC, but by adjusting the phase of the PMC LO to minimize the error signal it was able to lock. Phase was set to 247 degrees (90+157). REF value was set to 1.02V and gain is at 13dB.

PMC and ISS are locked. FSS is still refusing to lock, it has been turned off for now. LRA and watchdogs are enabled.

Additionally the PMC reflected power level channel does not seem to be connected, and the ante-room camera did not come back up. I've unplugged it for now.

Mark B. & Szymon S.

On Thursday June 7, 2012 we tried testing the L2 (penultimate mass) OSEMs after Jeff G. reported a problem with the upper right OSEM.

We saved a DTT template under: 
/ligo/svncommon/SusSVN/sus/trunk/QUAD/H2/ETMY/SAGL2/ETMY_L2_OSEM_testing_template

Shaking the top mass M0 in the longitudinal direction [H2:SUS-ETMY_M0_TEST_L_EXC] and monitoring the OSEM readback signals [H2:SUS-ETMY_L2_OSEMINF_UR_OUTMON] in DataViewer, we found that the UR OSEM was only responding with 1/5 of the amplitude as the other three OSEMs on that stage.

Setting up a 0.43 Hz (at around the first pendulum mode) sinusoidal drive with about 50 counts of amplitude in the reaction chain top mass [H2:SUS-ETMY_R0_TEST_L_EXC], we saw that there was no cross coupling between the main and reaction chains which indicates that they weren't rubbing together.

We then took a passive measurement of the L2 OSEMs, by looking at the power spectra of the channels:

H2:SUS-ETMY_L2_OSEMINF_UL_OUTMON
H2:SUS-ETMY_L2_OSEMINF_UR_OUTMON
H2:SUS-ETMY_L2_OSEMINF_LL_OUTMON
H2:SUS-ETMY_L2_OSEMINF_LR_OUTMON

In the attached plot we noticed that the UR OSEM on L2 did not have a magnitude consistent with the other three OSEMs around the 0.99 Hz mode.  We also picked up a transverse mode around 1.03 Hz from the UR, LR, and UL OSEM sensors - something that should not be present in these OSEMs, which are ideally only longitudinal sensors.  These features lead us to suspect that the stage L2 UR OSEM is misaligned, despite the painstaking efforts of members of the suspension team to get it right.

At this time, we don't think this problem merits going into the chamber to diagnose because of the delay that would be introduced from pumping.

Air drill brushing was completed early this afternoon and then the crew worked on hand-brushing. A total of five drills were used in this chamber:  four general purpose drills plus the dedicated brush for fins and rings.

I checked and documented the wipes that have been hanging in a flow-bench in the OSB Optics lab. The "last wipes" were taken in BSC2 on 25 May 2012 and have been exposed to air for ~15 days. There is no visible change in coloring. Please see pix attached.

ENDY pumpdown.

After 3 days. The glitch at 11:15 UTC (4:15 am local) is likely the gauge behavior.

Kyle and Gerardo are spraying helium today.

[Stuart A, Jeff B, Mark B, Jeff G]

Initial M1-M1 damped and un-damped transfer functions have already been taken for the PR3 (HLTS), see LHO aLOG entry 2649. Recently, magnets and AOSEMs have also been added to the lower stages (M2 and M3) to complete the full metal suspension, see LHO aLOG entry 2953.

As part of Phase 1b testing, these transfer functions can be compared with the model as well as TFs obtained from LLO's PR3 Phase 1b results. Also, since BOSEM and AOSEM sensors are available at all stages, power spectra can now be be taken.

Pre-flight checks have been carried out:-
- Confirmed watchdogs are configured to within accepted limits (see LHO aLog entry 2576).
- Confirmed M1 BOSEM INPUT FILTERS, gains and offsets (as per LHO aLog entry 2645).
- Configured M2 and M3 AOSEM INPUT FILTERS, gains and offsets:-

M2-UL s/n = 448, open-light = 18318.0, off-set =  -9159.0, gain = 1.638 
M2-LL s/n = 601, open-light = 20793.0, off-set = -10396.5, gain = 1.443 
M2-UR s/n = 336, open-light = 19426.0, off-set =  -9713.0, gain = 1.544
M2-LR s/n = 413, open-light = 18210.0, off-set =  -9105.0, gain = 1.647  

M3-UL s/n = 489, open-light = 17727.0, off-set =  -8863.5, gain = 1.692 
M3-LL s/n = 269, open-light = 23463.0, off-set = -11731.5, gain = 1.279
M3-UR s/n = 461, open-light = 25154.0, off-set = -12577.0, gain = 1.193
M3-LR s/n = 287, open-light = 17820.0, off-set =  -8910.0, gain = 1.684

- Configured COIL OUTPUT filter gains and signs, as specified in T1200015-v1. However, the sign has to be switched from - to + for the "side" BOSEM, since it has been relocated to the opposite side of the structure (as requested by SYS).

Firstly, I conducted some quick low-res M1-M1 TF's on all dofs in DTT (not recorded), just to confirm that no earthquake stops, blade stops or OSEM flags were rubbing since the last TF's were taken. The TFs obtained for Phase 1b testing of PR3 have now been compared with those obtained at previous phases of testing (allhltss_2012_06_07_AllHLTS_ALL_ZOOMED_TFs.pdf). 

Plot Key:-
Blue trace = Model
Orange trace = LLO PR3 Phase 1b at test-stand with damping OFF
Black trace = LHO PR3 Phase 1b at test-stand with damping OFF
Pink trace = LHO PR3 Phase 1b at test-stand with damping ON

Prior to taking power spectra data, it was necessary to enable the following DQ channels, so that data could later be extracted from the frames:-

X1:SUS-HXTS_M2_OSEMINF_LL_OUT_DQ
X1:SUS-HXTS_M2_OSEMINF_LR_OUT_DQ
X1:SUS-HXTS_M2_OSEMINF_UL_OUT_DQ
X1:SUS-HXTS_M2_OSEMINF_UR_OUT_DQ

X1:SUS-HXTS_M2_WIT_L_DQ
X1:SUS-HXTS_M2_WIT_P_DQ
X1:SUS-HXTS_M2_WIT_Y_DQ

X1:SUS-HXTS_M3_OSEMINF_LL_OUT_DQ
X1:SUS-HXTS_M3_OSEMINF_LR_OUT_DQ
X1:SUS-HXTS_M3_OSEMINF_UL_OUT_DQ
X1:SUS-HXTS_M3_OSEMINF_UR_OUT_DQ     

X1:SUS-HXTS_M3_OSEMWIT_L_DQ
X1:SUS-HXTS_M3_OSEMWIT_P_DQ
X1:SUS-HXTS_M3_OSEMWIT_Y_DQ

To ensure the above channels were available it was necessary to restart the framebuilder. 

Power spectra have been taken (using the Matlab script "plothlts_spectra.m") with damping loops both ON and OFF for each stage (2012-06-08_1800_X1SUSPR3_M*_ALL_Spectra.pdf)

Power spectra data, again with both damping ON and OFF have been taken, which compare X1 PR3 (at LHO) and X2 PR3 (at LLO) on the triple test-stands (allhltss_2012-06-08_ALL_Spectra_Don.pdf and allhltss_2012-06-08_ALL_Spectra_Doff.pdf).  

In addition, power spectra for specific degrees of freedom (L, P and Y) can be more conveniently compared across multiple stages (M1, M2 and M3) of the same suspension in the final plots found below (allhltss_2012-06-08_X1SUSPR3_M1M2M3_Spectra_ALL_Don.pdf).

A BURT snapshot has been taken of the latest PR3 functioning environment "20120606_x1sushxts_PR3.snap" and stored in the following directory:-
"/opt/rtcds3/tst/x1/cds_user_apps/trunk/sus/x1/burtfiles".

All data, plots and scripts have been committed to the SUS svn as of this entry.

This should now be sufficient to complete Phase 1b testing of the PR3 suspension.

Finally, thanks also to Jim Batch for being able to restart the trippleteststand when I was unable to log-in remotely earlier today.

Attached are plots of dust counts > .5 microns.

Pressure is moving slowly. Today the annulus system was evacuated with no noticeable impact. Tomorrow Gerardo will spray helium on new conflat joints.

For reference BSC8 reached 1e-6 torr in ~2 days with the same size turbo. ENDY has the additional load of the iLIGO stack.