We centerd the input of WFS QPD.

We found that the MC REFL image was no longer round and that the MCWFS DC quadrant spots were mostly
in one quadrant. So we re-centered the MCWFS beams in the following way:

1) We unlocked the MZ and adjusted the PZT voltage to keep the beam on the WFS from saturating.
2) Re-aligned the black hole beam dump to center its beam in its aperture.
3) centered the beam on the MCWFS optics and MCWFS QPD displays.
4) Relocked MC.

Below is the image of the IOO Strip tool. You can see that the MC REFL DC is now more flat. The
MC pointing has also been changed (see the MC TRANS HOR & VERT channels). The MC transmitted
light is also now more stable and higher.

We tried to center the QPD, and we found that there were a few hundred mV of dark offset for each 
quadrant of QPD. We adjusted them with this scripts:
/cvs/cds/caltech/scripts/MC/WFS/McWFS_dc_offsets

The power supply of a lock-in amp, which is on the Y-arm side of PSL clean room, was pulled out by my mistake.

Then I reconnected it, but I don't know whether it is re-adjusted properly.

I'm sorry about this. If you are using that amp, it should be checked.

On Monday evening, I ran this command: trianglewave C1:IOO-MC_REFL_OFFSET 0 4 120 600;ezcawrite C1:IOO-MC_REFL_OFFSET 1.76

which I thought (from the syntax help) would move that offset slider with a period of 120 seconds for 600 seconds. In actuality, the last argument is the

run time in number of periods. So the offset slider has been changing by 8 Vpp for most of the last day. Oops. The attached image shows what effect

this had in the MC transmitted power (not negligible). This would also make the locking pretty difficult.

In the second plot you can see the zoom in view for ~30 minutes. During the first part, the MCWFS are on and there are large fluctuations

in the transmitted power as the WFS offset changes. This implies that the large TEM00 carrier offset we induce with the slider couples into

the WFS signals because of imbalances in the quadrant gains - we need someone to balance the RF gains in the WFS quadrants by injecting

an AM laser signal and adjusting the digital gains.

Since there is still a modulation of the MC RFPD DC with the WFS on, we can use this to optimize the REFL OFFSET slider. The third plot

shows a 8 minute second trend of this. Looks like the slider offset of zero would be pretty good.

This morning, MC alignment was gone and MC wasn't lock.

We checked old value of pitch, yaw, and position offset of each MC mirror, and found they were jumped.

We don't know the reason of this jump, but we restore each offset value and MC backed to lock.

Kakeru and Kiwamu

We placed a QPD on the PSL bench for PSL angle monitor.

 As we mentioned before, old QPD which used to be placed is broken.

 And we put broken QPD into the "photodiodes" box under the soldering table.

We found the MC reflection was distorted . And WFC beam went to upward of QPD

We recentered WFC beam and these problems were fixed

Good settings for acquisition:
MC INPUT GAIN = 6 dB
40:4000        Disable
FAST polarity  MINUS
VCO Gain       -3 dB
MC LIMITER     Disable

FSS TEST1      TEST
FSS CG         -3 dB
FSS FG         13 dB

SUS-MC1_SENSOR_SIDE and SUS-MC2_SENSOR_UL are glitching

Yesterday's 4.8mag earthquake at Salton Sea is shown on Channel 1

[MC Board]
C1:IOO-MC_REFL_GAIN 14
C1:IOO-MC_REFL_OFFSET -4.2381
C1:IOO-MC_BOOST1 0   (You can turn it on if you want, but turn it off for locking)
C1:IOO-MC_BOOST2 0
C1:IOO-MC_POL 1   (Minus)
C1:IOO-MC_VCO_GAIN 4
C1:IOO-MC_LIMITER 1 (Disable)

[FSS box]
C1:PSL-FSS_SW1 0 (Test1 ON)
C1:PSL-FSS_INOFFSET 0.1467
C1:PSL-FSS_MGAIN 30
C1:PSL-FSS_FASTGAIN 14 (Do not increase it, at least while locking. Otherwise the phase lag from the PZT loop gets significant and the MC loop will be conditionally stable).

When all things fail (netgpibdata.py is giving me weird data.  When I plot the data it has saved from the 4395A, it's some wierd other universe's version of my transfer function.  I don't really know what's up.  I'm pretty sure I'm getting the 'correct' data, since each TF looks vaguely like it should, but with some crazy humps.  I'll talk to Yoichi in the morning about it maybe.) (also, we're low on emergeny floppy discs), you can always take a picture of the Agilent 4395's screen, as shown below.

* Mode cleaner and PMC are both relocked after my shenanigans, and I'll try again in the morning (I assume locking is going on tonight) to get real TF's with real data, as opposed to the photo method.

Note to self:  post the data of the TFs in the elog along with the plots, for posterity.

These TFs are of the Mode Cleaner servo board, exciting IN1 (or the 3.7MHz notch pomona box which is connected to IN1), and measuring at the SERVO out of the board.

One with the box, one without the box, and one of just the box for good measure.

 Yoichi, in all his infinite wisdom, reminded me that the netgpibdata script saves the data as the REAL and IMAGINARY parts, not the Mag and Phase.  Brilliant.   Using that nugget of information, here are the TFs that I measured earlier:

The last attachment is the .dat and .par files which contain the data and measurement parameters for the 3 TFs in the plots.

Yoichi, Pete

We ran cable from the suspension rack to the IOO rack to record the signals with DAQ channels.

The test channels:

UL coil      C1:IOO-MC_DRUM1  (Caryn was using, we will replace when we are done)

UL input   C1:IOO-MC_TMP1 (Caryn was using, we will replace when we are done)

LR coil      C1:PEM-OSA_SPTEMP

LR input   C1:PEM-OSA_APTEMP

We will leave these overnight; we intend to remove them tomorrow or Monday.

We closed the PSL shutter and killed the MC autolocker.

  Earthquake mag 4.0 at Lennox, Ca     trips MC2 watchdogs       http://quake.usgs.gov/recenteqs/Quakes/ci10411545.html

See 40m accelerometers as they see it.

[Clara, Jenne]

While Clara was working on her Wiener filtering and optimizing the locations of the accelerometers, she discovered that MC_L and MC_L_256 are totally flatlined.  I looked at them, and it looks like they've been dead since ~9:30pm-ish on Sunday night.  Bootfest-type activities shall commence shortly.

 Under Alberto's tutalage, I rebooted the whole vme set (iovme, sosvme, susvme1, susvme2), and after that MC_L was all good again.

 I'm impressed by Rana's simple way to align the MC. IFO arms are locked or flashing. 20 days trend attached.

Q. When should we use plano-convex lenses, and when should we use bi-convex?

As I had the same question from Jenne and Dmass in a month,
I just like to introduce a good summary about it.
Lens selection guide (Newport)
http://www.newport.com/Lens-Selection-Guide/140908/1033/catalog.aspx

At a first order, they have the same function.
Abberation (= non-ideal behavior of the lens) is the matter.

I tilted the periscope beam and aligned the MC.  Now the spot at the Faraday entrance is near the center of the aperture in up/down space.  The arm powers are only going up to ~0.8, though.  Maybe we should try a little bit of left/right. 

I looked at the IP POS spot with a viewer card, and it looked round, so no obvious egregious clipping in the Faraday.  Someone might take a picture with one of the GigE camera and get us a beam profile there.

We no longer have an MC1 and MC3 camera view.

I can see a bright scatterer that can be seen from the east viewport of the BSC, but I can't tell what it is.  It could be a ghost beam. 

It would be nice to get an image looking into the north viewport of the IOO chamber.  I can't see in there because the BS oplev table is in the way. 

I am (was) able to get the mode cleaner mostly locked, but because WFS2 wasn't centered, the MC would drift, then lose lock.  I recentered both the WFS (after unlocking the MC and the MZ), and am now about to commence relocking both of those.

/end{quick update}

Note to self:  WFS get centered based on the direct reflection from MC1.  Once the MC is close enough, the WFS are enabled, and they twiddle all 3 MC mirrors to minimize their error signal.  Moral of the story: make sure the WFS are centered.

The mode cleaner seems to be locking again.  I've manually unlocked it a few times in the past 20min, and most of the time it catches lock again (maybe about 80% of the time).  Other times, it starts to lock in a bad mode, and can't fix itself, so I unlock it, and let it restart and it usually does fine the second time around. 

I'd like it to be a little more robust, but I'm having a bit of trouble zeroing in on the optimal alignment for quickest, most durable lock aquisition of the MC.  Right now I'm going to leave it for a little while to make sure it doesn't fall apart.

Jenne, Koji, Rana

After fixing up the Mode Cleaner a bit more (fiddling more with the MC_align sliders to get the alignment before locking, making sure that it is able to lock), we noticed that the MC Trans path could use some help. To align the MC, we put MC1 and MC3 back into the position where Rob left it on Thursday and then maximized the transmission with MC2. Then we went back and maximized with MC1/3 keeping in mind the Faraday. We got a good transmission and the X-arm had a transmission of 0.8 without us touching its alignment.

Upon looking at the AP table portion of the MC_trans path, we decided that it was all pretty bad.  The light travels around the edge of the AP table, then out the corner of the table toward the PSL table.  A periscope brings it down to the level of the PSL table, and then it travels through a few optics to the MC_trans QPD. 

The light was clipping on the way through the periscope, and so the MC_trans QPD was totally unreliable as a method of fine-tuning the alignment of the Mode Cleaner.  Ideally we'd like to be able to maximize MC_trans, and say that that's a good MC alignment, but that doesn't work when the beam is clipped.

Things done:

1. The first turning mirror on the AP table after the beam comes out of the vacuum was changed from a 1" optic to a 2" optic, because the spot size is ~4-6mm.  We were careful to avoid clipping the OMCT beam, by using a nifty U200 mount (C-shaped instead of ring-shaped). 

2.  We placed a lens with a RoC of 1m (focal length for 1064nm is ~2m), a 2" optic, between the first two mirrors, to help keep the beam small-ish when it gets to the periscope, to help avoid clipping.

3. Rana adjusted the angle of the upper periscope mirror, because even when the beam was centered on the steering mirror directly in front of the periscope and the spot was centered on the first periscope mirror, the beam wouldn't hit the bottom periscope mirror. 

4. We noticed that the bottom periscope mirror was mounted much too low.  It was mounted as if the optics after it were 3" high, which is true for all of the input optics on the PSL table.  However, for the MC_trans stuff, all the optics are 4".  We moved the periscope up one hole, which made it the correct height.

5. We removed the skinny beam tube which guided/protected the beam coming off the periscope after a steering mirror since it (a) wasn't necessary and (b) was clipping the beam. We cannot use such skinny tubes anymore Steve.

6. There was a lens just before the 2nd steering mirror on the PSL table portion, which we removed since we had placed the other lens earlier in the path.  2 lenses made the beam too skinny at the QPD.

7.  After this 2nd steering mirror, there had been a pickoff, to send a bit of beam at a crazy angle over to the RFAM mon, which we removed.  This results in a much brighter beam at the MC_trans QPD, and at the camera.  The QPDs readouts are now a factor of ~3.5 higher than they used to be.  These (especially the camera) could use some ND-filtering action.

8.  The steering optic directly in front of the MC_trans QPD is a beamsplitter, and instead of dumping the light which doesn't go to the MC_trans QPD, we used this to go over to the RFAM mon (instead of the pickoff which we had removed). 

9.  Koji fixed up the optics directly in front of the RFAM mon, accomodating the new position of the input light (now at a much more reasonable angle, and about 15cm farther back from the PD). Note the beam dump which is preventing the cables from the FSS board from entering the beam path. This included removing an ND filter wheel, so the RFAM mon values will all be higher now.  Koji also has the beam going to the PD going at a slight angle, so that the beam isn't directly reflected on itself, so that it can be dumped.

10. We aligned the beam onto the MC_trans QPD using the first steering mirror on the PSL table.

11. We also removed the giant wall of beam dumps separating the squeezing section of the table from the rest of the table.

Alberto will elog things about the RFAM mon, including different values of the PD output, etc.

Still on the to-do list:

A.  Replace the second steering mirror on the AP table after the MC_trans light leaves the vacuum with a 2" optic, since the lens we placed isn't tight enough to make the spot small there yet.  Us a U200A mount if possible, because they are really nice mounts.

B.  Put an ND filter in front of the MC_trans camera, because the image is too bright.

C.  Normalize the MC_trans QPD - the horz and vert are pretty much direct voltage readouts, with no normalization.  They should be divided by the DC value.  This lack of normalization results in higher sensitivity to input pointing.

D.  Long term, next time someone wants to optimize the MC_trans path, move all the optics, including the MC_trans QPD and the camera closer to the periscope on the PSL table.  There's no reason for the beam to be traveling nearly the full width of the PSL table when we're not manuvering around squeezing stuff.

E. Never, ever purchase these horrible U100 or U200 mounts with the full ring and the little plastic clips. They are the "AC28" version. Bad, bad, bad.

Image 1:  The new setup of the AP table, Mc_trans portion. 

Image 2:  New setup of the MC_trans part of the PSL table.