This morning after the meeting Thomas and I actuated the motorized rotation stage in order to attenuate the laser power in the H1 PSL path. The shutter for both the main PSL beam and the ALS pickoff has been closed, locked and tagged. However, we also decided to decrease the power leaving the PSL table so that 8 W of light is not hitting the shutter for the duration of the vent.

The MEDM interface for the rotation stage has multiple functions, but the two main calls are to REQUEST ANGLE for the motorized stage or to REQUEST POWER being output after the light passes through the waveplate. Currently only the REQUEST ANGLE function is useful because of some missing calibration data. I will work to get this fixed so we can request a specific power or use the GO TO MINIMUM POWER function.

For now we plotted the power output as we rotated the stage and then manually requested an angle corresponding to the minimum. 63 degrees in this case, which corresponds to approximately 50mW of light entering the PSL light pipe. note that the ALS pickoff is before the motorized stage, so that path still has somewhere around 250mW of 1064nm light.

see attached for the plot of power and rotation angle

A certificate has expired on the local CDS LDAP replica which is preventing LIGO.ORG logins on some of the control room workstations (depending on when they were last rebooted, or last connected to the LDAP server).  For now, if you cannot log in to a workstation with your personal login, use the controls account instead.  I am looking at a workaround until the new certificate is issued, but that will take a while longer to roll out.

In light of the upcoming vent, it seemed like a good time test the ability of the test mass optical levers to recover from the venting, swapping and re-pumpdown. I've recentered the optical levers on 2014-06-02 17:05 UTC with the following status:

SUS values:

ITMX_Pit =  38.7

ITMX_Yaw = -48.9

ITMY_Pit =  193.4

ITMY_Yaw = -181.1

HEPI Isolated and biases are:

ITMX_RX =  -6020

ITMX_RY = -45350

ITMX_RZ =  71250

ITMY_RX =  44920

ITMY_RY =  48020

ITMY_RZ = -23500

ISI Stg1 Isolated and biases are:

ITMX_RX = -17600

ITMX_RY =  27450

ITMX_RZ =  30450

ITMY_RX =  9760

ITMY_RY = -28600

ITMY_RZ =  6760

ISI Stg2 Isolated and biases are:

ITMX_RX =  -4565

ITMX_RY = -680

ITMX_RZ =  7744

ITMY_RX =  19623

ITMY_RY = -12484

ITMY_RZ =  7496

LVEA transitioned to laser SAFE

Teams taking fiducial measurements (ITMs/ETMs/OpLevs)

Ready to vent all three corner station volumes after lunch

Good results from Thomas measurements on the stability of RH over the weekend

HAM4/5 doors and HAM6 septum in place

HAM6 SLED ready to install, on hold for now

need visual inspect on HAM6 cabling lengths

Apollo restoring beer garden cleanroom---coupling with BSC1/3

installation of TCS table stops on hold

need to lock HEPI for BSC1/3 due to potential contact with HEPI crossbeams

need to protect TCS mirrors during in chamber work

The particulate mobility experiment that is mounted to HAM 3 is back up and running.  It will be running for the next 3 days to make sure the entire vent cycle is captured.

Betsy, Sheila, Keita, Arnaud, Thomas

Here is a snap shots of the current alingment offsets. This alingment was checked quickly this morning, both of the arms are flashing green so the ITMs are within a urad or so of alinged. 

We noticed that the ailngment of ITMY was off by about 8 urad in pitch from the saved offset, this seems to be because turning on and off the ring heater changes the ailngments.  Attached are trends of the OpLevs durring the ring heater stress test this weekend, the itms moved by 2-5 urad in yaw, and both moved by about 30 urad in pitch. The third screenshot shows how the pitch changed as the ring heater power cycled.

no restarts reported.

D. Hosken, G. Grabeel, T. Vo

We were able to fix the ring heater chassis EtherCAT wiring by referencing the drawings.  We initially turned both ITM ring heaters to 30 Watts at 6:46 PM PT but it seems as though the maximum power that the drivers can put out is ~15-16 Watts so we changed the script that Greg wrote to run the power at 13.5 Watts during the high power portion and .5 Watts in the low power portion.  I'll come in tomorrow morning to run some trends and take some measurements.  John verified in the first hour that there were no spikes in pressure.

It looks like we will need to go in chamber at end X to fins IR on the QPDs.  I searched for the beam today by locking ALS, and moving the picomotor for M4 to toward the position that Kiwamu et al found in February (alog 10091).  This was fine for the Y direction, but in the X direction I only got about a quarter of the way toward the old position before the green transmitted power started to drop.  One theory is that this could be the green clipping on the mount for M4 (TMS table drawing).  After a little bit of searching around, I decided move the picomotors back to the position that we had set them to to restore the beam on the table. 

The positions used to get IR onto the LSC PD from February until yesterday were 9267 X 1665 Y for M4.  Today after moving the picomotor around quite a bit, I needed to use 27357 for X and -12616 for Y to restore the beam to the same position.  So these numbers are meaningless as references. 

If you remove the snout from the LSC TRX PD in air, there are two brighter green spots (with two very faint spots below them to form a square, right now the lower ones are clipped upstream).  The one that is slightly brighter and on the side of the PD face that is closer to the chamber is the one that is co-linear with the IR, and could be used as a reference if we decide to send IR into the chamber from this path to align the QPDs. 

Yesterday Daniel noticed that the beam was clipped on EX WFSA, but the beam was not centered either and we were in the middle of IR beam finding. Today I centered the beam and it was still clipped because the beam was coming to the WFS head at much shallower angle than it should be. I fixed it by tilting the WFS head.

I and Daniel went to EY and tested WFSB using AM laser, and we saw that some of the channels were a factor of 5 or so smaller than the others.

Eventually we tracked it down to the WFSB whitening chassis (S1101602) though I thought it was working OK on Thursday (https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=12138),

We tested S1101601 that was pulled out earlier this week that was suspicious unit but was never conclusively diagnosed bad, and it didn't work. So we got another spare unit (S1101638) from the corner station and  put it in.

What are in use now: S1101600 for WFSA, S1101638 for WFSB.

Bad units: S1101601, S1101602, S110163.

Bad ones are put on a table in EY.

model restarts logged for Fri 30/May/2014
2014_05_30 14:42 h1fw0

unexpected restart of h1fw0

John Worden, R. Weiss
Vibration measurements of the beamtube with the new R10 insulation and aluminum jacket were made and described in the
appended document. The new insulation reduces the acoustic coupling to the beamtube but not as well as the initial insulation.
The data enables a more detailed estimate of the phase noise from the beamtube motion due to the faulty HR coatings of the new 
test mass mirrors. The DCC number of the document is T1400384.

(Keita, Daniel)

Today we measured and adjusted the gain/phase of the WFS RF signals. WFS_A looks fine, but WFS_B has segments 3 and 4 which are ~10x smaller than 1 and 2. Engaging DOF4 did result in a stable feedbakc but with a rather large offset. We added an offset to segment 4 of WFS_B to recover. Adding DOF3 did not result in a stable feedback.

Playing around with the individual pit/yaw offsets and the WFS DC centering one can find feedback topologies with all 4 DOFs engaged. However, they are susceptible to disturbances.

When the septum was removed, the cabling between HAMs 5 & 6 were disconnected so the crew could deal with all the bolts.  I asked FClara to reconnect the cables to the WHAM6 NW feedthru, SUS & ISC I think.  I'm not familiar enough to distinguish these so I left those to him.  When they are sorted out I will complete the cable/feedthru protecting.
Meanwhile, HAM5 ISI sensors are live, don't disconnect any cabling, you'll have to cut zip ties to do so.