Will the true 00-mode please stand up!

(Daniel, Stefan)

Based on yesterday's mode scan we identified where the 00 mode should be (tiny peak, with transverse modes spaced at 17890Hz to the right).

We did a dither alignment, first green (moving TMSY, ITMX and ETMX), then locked on the now identified 00-mode (moving PR2 and IM4).
That gave us 500 cts in the transmission quad sum (up from 250 counts).

Attached is the mode scan after the alignment.

We also used the opportunity of having measured the 00 mode offset frequency in a grossly misaligned state.
We can set a limit on the effecy of alignment on frequency offsets.

00-mode in grossly misaligned state (yesterday): -22842Hz
00-mode in aligned state (today):                -22856Hz

The difference is only 14Hz. Given that both numbers were derived by finding the top of the fringe with about 10Hz RMS fluctuations, the error in that measurement is also about 14Hz.

Cavity Mode Scan

(Daniel, Stefan)

First we realized that the 10x higher fluctuations we obserbed on Wednesday were entirely due to alignment. So we tweaked up what we thought was the carrier, and indeed reproduced the ~8Hz RMS performance.

At this stage we rand a mode scan (attached, plots 1 sand 2). The two attached plots are from two adjacent locks - they differ by 1/2 FSR, as expected.
For the 2nd one, the modes sit at

H1:ALS-C_COMM_VCO_TUNEOFS = [-4.744, -3.242, -1.882, -1.638, -0.380,  0.877,  2.187,  3.557,  3.837,  5.348]  V
Frequency offset           =[-62075, -44240, -26212, -22842, -05055,  12770,  30803,  48585,  52070,  69855] Hz

The transverse mode spacing 8945Hz ( 17890 Hz on the VCO)
The odd this is that the frequencies make most if the 10 mode is the biggest.

We also redid the transmon camera and LSC diode, taking out the ND filter which distorted the view. While the new image is not distorted, we still don't get a nice modal picture. Not sure why.

Here is another mode scan after the alignment drifted off more.

We now suspect that we maximized the wrong mode.

Green sidebands

Yesterday we found a rather large contamination in the corner ALS COMM signal. There is highly non-stationary line around 24.5 MHz. Suspecting this maight be the green RF sidebands that are leaking through, we went to EY to look for their exact location. Measuring the transfer function from the FIBR servo to the PDH error signal, we were unable to identify the sidebands. Next, we took a close look at the notch feature which marks the first FSR. It is located at FSR = 37.4658 kHz with an uncertainty of 0.1Hz. The 3 dB points (down from the flat part) are at 37.426 kHz and 37.506 kHz, 80 Hz wide.

The cavity length then becomes FSR / 2 / c = 4000.88 m.

The RF frequency is f_M = 24.515730 MHz. Dividing by the FSR we get
f_M / FSR = 654.350, or in other words the sidebands ar expected at 0.35* FSR =  13.113 kHz +/- 0.065 kHz.

Looking again at the full sweep and zooming in near 13.1kHz we indeed see a tiny feature in the phase plot around 13.188 kHz. It moves to 12.868 kHz when the RF sidebanda frequency is lowered by 300 Hz.

The only other features in the sweep which are clearly identifyable are at 17.739 kHz and 19.731 kHz symmetrically around half the FSR. These are most likely the second order modes. Dividing 17.739 kHz by 2 we get a corresponding mode spacing of 8.87 kHz. For OAT the mode spacing was measured at 8.92 kHz with a different ITM at a different position.

(Daniel, Stefan)

The spurious frequency we observed at the corner beat node is 24.5025 MHz. This is inconsistent with the end station pdh signal.

This signal fluctuates between -25dBc and -8dBc  (-55dBm to -38dBm, with the beat node sitting at -30dBm).

We left a Minicircuit 50MHz high pass in that line - this fixed the glitches in the PFD.

VCO work

(Stefan Daniel)

We moved the additional frequency difference divider to the common VCO. This required an increase of the PLL gain from 5 to 20. The unity gain was measured to be around 40 kHz. This also means that the gain for the common mode feedback increased by 10. We adjusted by lowering the gain of the SR560 from 10 to 1.

We took the opportunity to set all VCOs to a nominal frequency. The nominal frequency of the PSL/IMC VCO and the fiber AOM driver is 79'200'000 Hz. All ALS VCOs (EX/EY, COMM, DIFF) are set to a nominal frequency of 78'920'000 Hz.
 

Nominal frequencies at 532 nm

Location	Frequency (Hz)	Comment
Fiber	–79'200'000 x 4	downshift
PSL	–79'200'000 x 4	downshift, laser relative to ref. cav.
EX laser	–78'920'000 + fiber	relative downshift
EY laser	+78'920'000 + fiber	relative upshift
COMM VCO	+78'920'000
DIFF VCO	+78'920'000
Beat EX/laser	–78'920'000	fiber - PSL + EX laser
Beat EY/laser	+78'920'000	fiber - PSL + EY laser
Beat EY/EX	+157'840'000	EY laser - EX laser
EX invariant	0	fiber - PSL + EX laser + COMM VCO
EY invariant	0	fiber - PSL + EY laser - COMM VCO
DIFF invariant	0	EY laser - EX laser - DIFF VCO

 

The lasers in the end stations can be locked up or down by changing the sign of the phase frequency discriminator.

MSR room doors to hallway open for cooling

Due to cooling issues with the MSR, we have left the double doors between the MSR and the hallway opened for this weekend. We have set up a fan which blows the hot air at the rear of the racks out into the hallway. Please do not close the doors of move/obstruct the fan.

I have a script running which emails the MSR room temperature to CDS staff hourly, we will monitor the room over the four day weekend. We have contingency plans set up if we experience any further AC problems.

TMS-X Status

   The TMS-X suspension is mounted on the Bosch frame at End-X and the dummy mass table is suspended. The table is hanging almost level with no adjustments. The Upper Mass blades look to be in their correct position. The Upper Mass is still in stops, so we won't get a good read on how things are really hanging until the Upper Mass is leveled and suspended. This will be one of the first agenda items for next week.

  No real issues were encountered during the installation of the Upper Structure or with suspending the dummy mass table. The dummy table may be a bit low, but we will not know until we take some measurements.

  The Genie is parked under the dummy mass table as a safety stop during the long weekend. 

HAM6 Chamber Side Testing - Done

After pleny troubleshooting of minor electronics issues, we finally got to the point where we could check out the newly-installed sesnors of HAM6-ISI.

Sensors look fine. We can shoot for installation next week. Spectra are attached.

 

Note: One of the preamps of the HAM5-ISI ADE boxes (H3) needs fixing. It was used while HAM6's ADE was getting fixed. Symptom was a gain of 1/2 on the spectra of H3

Ops Day Summary

Alignment tweaking on RefCav (Rodruck)

Investigating Dust Monitors at EY (Patrick).  EY Dust Monitor-2 is exhibiting odd behavior.  The 0.3um readings are several 100,000 counts (while 0.5 is zero). 

PCal work in H2psl (Colin, Pablo)

Truck came by to pick up barrel from Flammable Storage Bunker.

TMS Suspension work at EX (Andres, Jeff B)

TMS Telescope work at EX (Keita)

HAM6:  GS13 cards swapped, cps interface investigations continue

SURF Student (Emily) will mount accelerometers on Southern doors of HAMs 4&5.

Helium removal

Valved-out YBM MTP @ 1530 -> 2.2 x 10-7 torr*L/sec indicated

Ref cav alignment

I aligned the reference cavity to give ALS more light into their fiber. The TPD voltage increased from 1.1 V to 1.8 V, but I could not get it higher. I believe it used to be around 2 V before the laser shut off this last weekend.

I increased the Common gain to 29 dB to give a UGF of 400 kHz. The light on the RFPD is quite low, around 200 mV, hence the large amount of gain.

HAM6 ISI aLIGO HAM ISI Interface Chassis

Replaced power board D1001975 inside aLIGO HAM ISI Interface Chassis S1201747.
Replaced two AD8672ARZ Opamps inside aLIGO HAM ISI Interface Chassis S1201746. 

Units were cabled with external cables (3 Pin power cables) that feed power to CPS units. Before powering up the CPS units, I used a voltmeter to see the output at the end of the cable and discovered a 7 volt drop on the minus leg. The cables had the third pin tied to shield. This drew excessive current from the power board. The connection to the shield was disconnected from pin three. When the ISI Interface units were powered back on, the power board had one of the rails dead and AD8672ARZ outputs were railing on one of the GS-13 boards.

More SUS screen cleanup

Further to SUS screen cleanup in alogs 6926 and 6893, I went through the whole $(USERAPPS)/sus/common/medm/quad directory, checking that all linked screens were supplied with a full set of arguments via the argument macro files. I opened each file in gedit and searched for the "args=" lines corresponding to the Arguments fields of the Related Display Data dialog in the MEDM editor. Because nearly all the links were between generic screens but for the same optic I used the following args string:

args="%(read $(USERAPPS)/sus/common/medm/sus$(optic)_overview_macro.txt),USERAPPS=$(USERAPPS),SITE=$(SITE),site=$(site),IFO=$(IFO),ifo=$(ifo)"

Everything worked, so I committed the mods. As time permits I'll do the same for all the other suspension types.

Files updated today:

SUS_CUST_MAIN_MENU.adl - did token cleanup because probably not used. Made H2 and L1 specific calls generic but didn't remove FMx/FMy stuff.

SUS_CUST_QUAD_DACKILL.adl - 2 args lines updated.

SUS_CUST_QUAD_L1_CENTERING.adl - 6 args lines updated.

SUS_CUST_QUAD_L1_WD.adl - 6 args lines updated.

SUS_CUST_QUAD_L2_CENTERING.adl - 6 args lines updated.

SUS_CUST_QUAD_L2_WD.adl - 3 args lines updated.

SUS_CUST_QUAD_L3_OPLEV.adl - 3 args lines updated.

SUS_CUST_QUAD_M0_CENTERING.adl - 8 args lines updated.

SUS_CUST_QUAD_M0_WD.adl -  4 args lines updated.

SUS_CUST_QUAD_R0_WD.adl - 4 args lines updated.

SUS_CUST_QUAD_R0.adl - 14 args lines updated.

SUS_CUST_QUAD_R0_CENTERING.adl - 8 args lines updated.

FIles modified previously (alogs 6926 and 6893):

SUS_CUST_QUAD_OVERVIEW.adl - 64 args lines and 6 name lines updated.

SUS_AUX_QUAD_OVERVIEW.adl - 1 args line and 1 name line updated.

No action required: SUS_CUST_QUAD_IPC.adl, SUS_CUST_QUAD_ADC_MONITOR.adl, SUS_CUST_QUAD_L1_CENTERING_??ZOOM.adl, SUS_CUST_QUAD_L1_COILOUTF.adl, SUS_CUST_QUAD_L1_DAMP.adl, SUS_CUST_QUAD_L1_EUL2OSEM.adl, SUS_CUST_QUAD_L1_DRIVEALIGN.adl, SUS_CUST_QUAD_L1_LOCK.adl, SUS_CUST_QUAD_L1_OSEM2EUL.adl, SUS_CUST_QUAD_L1_OSEMINF.adl, SUS_CUST_QUAD_L1_SENSALIGN.adl, SUS_CUST_QUAD_L1_TEST.adl, SUS_CUST_QUAD_L1_WD_ACT_BANDLIM.adl, SUS_CUST_QUAD_L1_WD_OSEMAC_BANDLIM.adl, SUS_CUST_QUAD_L1_WD_OSEMDC_BANDLIM.adl, SUS_CUST_QUAD_L2_OSEM_ALIGN_??ZOOM.adl, SUS_CUST_QUAD_L2_COILOUTF.adl, SUS_CUST_QUAD_L2_DAMP.adl, SUS_CUST_QUAD_L1_DRIVEALIGN.adl, SUS_CUST_QUAD_L2_EUL2OSEM.adl, SUS_CUST_QUAD_L2_LOCK.adl, SUS_CUST_QUAD_L2_OSEM2EUL.adl, SUS_CUST_QUAD_L2_OSEMINF.adl, SUS_CUST_QUAD_L2_SENSALIGN.adl, SUS_CUST_QUAD_L2_TEST.adl, SUS_CUST_QUAD_L2_WD_ACT_BANDLIM.adl, SUS_CUST_QUAD_L1_WD_OSEMAC_BANDLIM.adl, SUS_CUST_QUAD_L2_WD_OSEMDC_BANDLIM.adl, SUS_CUST_QUAD_L3_DRIVEALIGN.adl, SUS_CUST_QUAD_L3_ESDOUTF.adl, SUS_CUST_QUAD_L3_EUL2ESD.adl, SUS_CUST_QUAD_L3_ISCINF.adl, SUS_CUST_QUAD_L3_LOCK.adl, SUS_CUST_QUAD_L3_OPLEV_MTRX.adl, SUS_CUST_QUAD_L3_OPLEV_SEGS.adl, SUS_CUST_QUAD_L3_TEST.adl, SUS_CUST_QUAD_L3_WD.adl, SUS_CUST_QUAD_M0_CART2EUL.adl, SUS_CUST_QUAD_M0_OSEM_ALIGN_??ZOOM.adl, SUS_CUST_QUAD_M0_COILOUTF.adl, SUS_CUST_QUAD_M0_DAMP.adl, SUS_CUST_QUAD_M0_DCDRIVECAL.adl, SUS_CUST_QUAD_M0_DRIVEALIGN.adl, SUS_CUST_QUAD_M0_EUL2CART.adl, SUS_CUST_QUAD_M0_EUL2OSEM.adl, SUS_CUST_QUAD_M0_ISIINF.adl, SUS_CUST_QUAD_M0_LOCK.adl, SUS_CUST_QUAD_M0_OFFLOAD.adl, SUS_CUST_QUAD_M0_OPTICALIGN.adl, SUS_CUST_QUAD_M0_OSEM2EUL.adl, SUS_CUST_QUAD_M0_OSEMINF.adl, SUS_CUST_QUAD_M0_SENSALIGN.adl, SUS_CUST_QUAD_M0_TEST.adl, SUS_CUST_QUAD_M0_WD_ACT_BANDLIM.adl, SUS_CUST_QUAD_M0_WD_OSEMAC_BANDLIM.adl, SUS_CUST_QUAD_M0_WD_OSEMDC_BANDLIM.adl, SUS_CUST_QUAD_ODC.adl, SUS_CUST_QUAD_R0_OSEM_ALIGN_??ZOOM.adl, SUS_CUST_QUAD_R0_COILOUTF.adl, SUS_CUST_QUAD_R0_DCDRIVECAL.adl, SUS_CUST_QUAD_R0_DAMP.adl, SUS_CUST_QUAD_R0_DRIVEALIGN.adl, SUS_CUST_QUAD_R0_EUL2OSEM.adl, SUS_CUST_QUAD_R0_OPTICALIGN.adl, SUS_CUST_QUAD_R0_OSEM2EUL.adl, SUS_CUST_QUAD_R0_OSEMINF.adl, SUS_CUST_QUAD_R0_SENSALIGN.adl, SUS_CUST_QUAD_R0_TEST.adl, SUS_CUST_QUAD_R0_WD_ACT_BANDLIM.adl, SUS_CUST_QUAD_R0_WD_OSEMAC_BANDLIM.adl, SUS_CUST_QUAD_R0_WD_OSEMDC_BANDLIM.adl

EX TMS Work Yesterday (Tues)

(Andres, Corey, G2, Jeff, Keita)

Upper Mass Suspension

Andres, Jeff, & G2 delivered their Upper Mass Suspension from the Staging Bldg to the EX TMS Lab.  It was a tight fit & a shuffle to move the Upper Mass In A Box in the TMS Lab, but we were able to get the Box & Genie positioned under the Bosch Frame.  These guys will stay here for a while...

This is because there is an issue with the Blade Springs for the Upper Mass.  As it was built the springs are too stiff so it would be hard to have a double pendelum.  The solution for this is to re-machine the Angle Bases for the springs (and possibly add a little more weight).  The Bases are being machined today (Wed), and should be in an Oven today for baking over the long weekend.  Once they are Class-A, the SUS crew will need to swap them out (as a cartridge).  This will be done from the "ground" or with the Upper Mass "in the air" clamped to the Bosch Frame.

Telescope

Telescope work is on hold due to ugly mirrors.  It has been confirmed by Garilynn at CIT that the 6" Alignment Mirror from LHO is an acceptable mirror.  It is currently en route back to LHO (to be received today or Monday).  Once we have it, procedures for cleaning this optic are next (tbd offline).  Once we have this mirror is cleaned, we can finally begin alignment of these mirrors.  

Misc

• Spent time with clean up to clear space for a SUS workspace.
• We have "rain" from the AC unit in the lab.  Condensation from the AC Unit has been "raining" a few cups of water in the lab.
• Continue search for cables
• Photos of progress continue

high .3 micron dust counts at end Y

Corey G. told me that the dust monitor at location 2 in the end Y VEA had started reading exceptionally high counts at .3 microns, but nothing at .5 microns. I went out to take a look, but didn't find anything obvious to account for it.

However, this dust monitor was shoved up against the west side of BSC 10 under the beam tube. I moved it farther southwest out into the VEA. The dust monitor at location 1 was near a table next to the electronics racks and I moved it northwest away from the table. I will post pictures of them before and after the moves once I can get them off my phone.

Pictures attached.

WBSC6/10-EndY HEPI Pump Servo Restarted with New database & medm control

re WPs 4012 & 3884, I brought down & restarted the HEPI Pump Station Pressure maintenance servo yesterday.  I am working on an operations manual but for now know that the FWD button inside the Pump Station Control Panel has been hardwired and the Pump will respond as the Medm directs as soon as the Green start button is pressed on the PS Control panel.  This is only needed in the case of a Power Outage or Reservoir Level trip.

Anyway, attached are the old (boring) and the new (ever so exciting) control medms.  I snapped the EndX screen but EndY looks the same.  In general, the operator needs to do nothing with this system.  If anything takes the pressure down, the bottom line is to make sure the output of the medm or the Setpoint is zero'd before pushing the green start button on the Pump Station Controller.  The output or setpoint is then slowly ramped up(a few psi at a time) by the operator (could/should be automated) to minimize any great shakes of the HEPI/ISI/Optics in chamber.

ETM03 PUM in oven.

As of 4:30 this afternoon, Gerardo and Gerardo Jr. were in the process of loading the replacement PUM into the airbake oven, the last step needed before use in a monolithic suspension. Tomorrow morning it can go to an end station for welding. Knock on wood. Well done powering thru placing 2 prisms and 4 magnet mounts, cure times included, in 2 days, guys.

Great Job Gerardo^2!

Your fast work is really appreciated.  Marty