The ITMY 10" flange with 10 DSUB-25 feedthroughs has been installed with the cables connected at the in-vac side.  This is the first of two flanges, and includes 5 cables ordered vertically in stacks of 3 & 2 for [[OMC-DCPDs, OMC-QPDs, OMC-PZTs/Pico]] and [[SRM1, SRM2]] respectively from right to left. During installation, two 12-point silver plated bolts were stripped, so Chub had to replace them.

[Paco, Chub]

The ITMY 10" flange with 4 DSUB-25 feedthroughs has been installed with the cables connected at the in-vac side. This is the second of two flanges, and includes 4 cables ordered vertically in stacks of 2 & 2 for [[AS1-1, AS1-2, AS4-1, AS4-2]] respectively. No major incidents during this one, except maybe a note that all the bolts were extremely dirty and covered with gunk, so we gave a quick swipe with wet cloths before reinstalling them.

[Lydia, Gautam, Koji, Johannes]

Summary of things done today:

• Rebalanced ITMY table
  • After waiting until today to see if the table would relax into a level position, engaged the earthquake stops for SRM and moved the large counterweight by ~4 inches. The table is now level to within ~0.1 mrad in direction of the access port
  • Since the relaxing seems to take some time, we will open ITMX and ETMX chamber tomorrow and level the tables with additional weights, so the springs can get used to 'levelness' again
• Cleaned ITMY, SRM and SR2 optics
  • Koji drag-wiped all three optics and cleaned the table in general where accessible. He was able to remove the sliver discussed in elog https://nodus.ligo.caltech.edu:8081/40m/12455
  • We measured the particle count in the chamber and found it to be 4000 for 0.3 microns and 660 for 0.5 microns.
• We pulled out stops on ETMY ITMY and roughly centered the OSEMs half-way, using photos of the previous OSEM rotation as a reference point for their orientation. We foudn that the green beam is hitting ITMY almost centered and that the reflection doesn't seem to steer off too much, but were not yet able to see any returned light on the ETMY cameras.

Unless we get lucky and get the green light to flash in the cavity by playing with the mirror alignment, we will open the ETMY chamber tomorrow. On one hand we can look for the reflected green light in the chamber, or alternatively the IR beam transmitted by ITMY. This way we can obtain estimates for the OSEM biasing and perform the final centering of the OSEMs. We will then also address the bounce mode minimization in ITMY and check if the previous orientations still hold.

While Anjali is working on the 1um MZ setup, the pesky ITMY was liberated from the OSEMs. The "algorithm" :

• Apply a large (-30000 cts) offset to the side coil using the fast system.
• Approach the zero of the YAW DoF from -2.00V, PIT from +10V (you'll have to jiggle the offsets until the optic is free swinging, and then step the bias down by 0.1). At this point I had the damping off.
• Once the PIT bias slider reaches -4V, I engaged all damping loops, and brought the optic to its nominal bias position under damping. 

While doing this work, I noticed several errors corresponding to EPICS channel conflicts. Turns out the c1susaux2 EPICS server was left running, and the MEDM screens (and possibly several scripts) were confused. There has to be some other way of testing the new crate, on an isolated network or something - please do not leave the modbus service running as it potentially interferes with normal IFO operation. For good measure, I stopped the process and shut down the machine since I saw nothing in the elog about any running tests.

I renamed all channels on c1susaux2 from "C1:SUS-..." to "C1:SUS2-..." to avoid contention. When the new system is ready to install, those channel names can be reverted with a quick search-and-replace edit.

As it turns out, now ITMY has a tendency to get stuck. I found it MUCH more difficult to release the optic using the bias jiggling technique, it took me ~ 2 hours. Best to avoid c1susaux reboots, and if it has to be done, take precautions that were listed for ITMX - better yet, let's swap out the new Acromag chassis ASAP. I will do the arm locking tests tomorrow.

With Chub providing illumination via the camera viewport, I was able to take photos of ITMY this morning. All the magnets look well clear of the OSEMs, with the possible exception of UR. I will adjust the position of this OSEM slightly. To test if this fix is effective, I will then cycle the bias voltage to the ITM between 0 and the maximum allowed, and check if the optic gets stuck.

[gautam, johannes, lydia]

Today we installed ITMY into position in the chamber.

• First, we took the F.C coat off both faces
• A stream of ionized nitrogen was used during the peeling process. We took as much care as possible not to blow towards the SRM. 
• F.C. films came off smoothly. But when we looked at a picture we took prior to putting the optic in place, it looks like there may be a sliver of F.C. left on the optic. There are also a few specks of dust visible on the HR face, but well away from the clear aperture (see Attachment #1). Do we want to use isopropanol + optical tissue to try and remove these?
• After F.C removal, we moved the optic into place against its stops. Returned OSEM connector tower to approximately its original place as it was moved to facilitate shifting the ITM to the edge of the table. 
• I cleaned up the tangled mess of OSEM connector wires. On the ITMY tower, the OSEM cables have been tied using pieces of thin copper wire so as to avoid the wires straying into the beam path. Checked that wires are in grooves on both sides.
• Unfortunately we were not able to start on setting up a cavity today, because when we checked the leveling of the ITM, we found that it was significantly not level. This is probably because the ITM was at the edge of the table. The cage is rather heavy and the location it was put in had a large lever arm. In any case, the table is slowly relaxing back to their usual state, Steve recommended we leave it overnight.
• Other issues:
  • the UL sensor on ITMY also seemed to show some evidence of glitchy behaviour. Looking in the Satellite box, I didn't see any obvious probelms like I did for the ETMY box (for which I am not even sure if I did a legitimate fix anyways). I guess we have to keep observing and think about doing something about this if it really is problematic.
  • SRM barrel is pretty dusty. So is SR3. Do we want to clean these? If so how? F.C. or isoprop drag wipe?

We did some quick checks with the green beam and the IR beam. With the help of the custom Iris for the suspension towers, we gauged that both beams are pretty close to the center of the test mass. So we are in a not unreasonable place to start trying to align the beam. Of course we didn't check if the beam makes it to the ETM today.

The SRM OSEM sensor problem seems to have been resolved by moving the ITM back to its place as we suspected. The values are converging, but not to their pre-vent values (attachment #2). We can adjust these if necessary I guess... Or perhaps this fixes itself once the table returns to its neutral position. This remains to be monitored.

In the never-ending B-R mode reduction saga - we found what we think is an acceptable configuration now. Spectrum attached (Attachment #3). The top two OSEMs are now nearly 90 degrees rotated, while the bottom two are nearly horizontal. Anyways I guess we just have to trust the spectra. I should also point out that the spectra change rather significantly from measurement to measurement. But I think this is good enough to push ahead, unless anyone thinks otherwise?

https://nodus.ligo.caltech.edu:30889/detcharsummary/day/20170114/sus/susdrift/

ITMY is not like the others. Real or just OSEM madness?

 I've got the bench set up for the measurement of the beam spot change with DC SRM alignment offsets. The ITMY oplev is aligned and fine to use, but the SRM one isn't until further notice (probably a couple of hours).

The ITMY mirror was released. The OSEM readouts became healthy.

To see what is going on, I changed the PIT DC bias slider on ITMY from 0.8 to -1 or so, and then the optic started showing a free swinging behavior.

If there were no responses to the DC bias, I was going to let people to open the chamber to look at it closer, but fortunately it released the optic.

Then I brought the slider back to 0.8, and it looked still free swinging. Possibly the optic had been stacked on some of the OSEMS as Jamie expected.

This work happened on Friday, after Nodus and the elog went down....

[Jenne, Kiwamu]

The guiderod and standoff for ITMY were epoxied, and left drying over the weekend on the flow bench under a foil tent.  The flow bench was off for the weekend, so we made tents which hopefully didn't have any place for dust to get in and settle on the mirrors.

There is a small chance that there will be a problem with glue on the arm of the fixture holding the guiderod to the optic.  Kiwamu and I examined it, and hopefully it won't stick.  We'll check it out this afternoon when we start getting ready for gluing magnets onto optics this afternoon.

ITMY, which is supposed to be fully free-swinging at the moment, is displaying the tell-tale signs of  being stuck to one of it's OSEMs.  This is indicated by the PDMon values, one of which is zero while the others are max:

UL: 0.000
UR: 1.529
LR: 1.675
LL: 1.949
SD: 0.137

Do we have a procedure for remotely getting it unstuck?  If not, we need to open up ITMYC and unstick it before we pump.

ITMY sus damping restored.

ITMY table re-leveled; AS1 damping restored

Attachments 1,2 show the starting state of the ITMY table weights. The e-bubble reading was different from close-out after removing the BHD optics, and fluctuating more than before:

Our goal: (x,y) = (+0.03, +0.17). So regardless of the fluctuation, weight needed to be shifted to the right and forward (from standing at chamber door). 

The final state of the weights is in Attachment 3,4. The final e-bubble reading was back to (x,y) = (+0.03, +0.17) ± 0.01.

After this, AS1 was able to damp [Attachment 5].

Next steps

Open BS chamber and confirm AS beam alignment.

First of all I moved the lenses on the ITMY/SRM oplev path to get a smaller spot size on the QPDs. I couldn't get the beam analyzer to work though, so I don't know quite how successful this was. The software brought up the error "unable to connect to framegrabber" or something similar. I don't think the signal from the head was being read by the software. I will try to get the beam analyzer working soon so that we can characterize the other oplev lasers and get decent spot sizes on the QPDs. I searched the elog for posts about the analyzer, and found that it has been used recently, so maybe I'm just doing something wrong in using it. 

After this I measured the transfer function for the ITMY oplev yaw. I did a swept sine excitation of the ITMY in yaw with an amplitude of 500, and recorded the OSEM yaw values and the oplev yaw values. This should show a flat response, as both the QPD and the OSEMS should have flat frequency response in the measurement band. This measurement should therefore just yield a calibration from OSEM yaw to oplev yaw. If the OSEM yaw values were already calibrated for radians, we would then immediately have a calibration from oplev yaw values to radians. However, as far as I'm aware, there is not a calibration factor available from OSEM yaw values to radians. Anyway, the TF I measured did not appear to be very flat (see attached plot). Kiwamu suggested I should check the correlation between the OSEM measurements and the oplev QPD measurements - if the correlation is less than 1 the TF is not reliable. Indeed the coherence was poor for this measurement. This was probably because at frequencies above the pendulum frequency, the excitation amplitude of 500 was not enough to cause a measurable change in the optic angle. So, the plot attached is not very useful yet, but I learned something while making it.

Why ITMY UL can not see this earth quake? SRM and PRM are misaligned. ETMX is still not well.

We have to remember to check OSEM - magnet alignment when vented.

Everybody is happy, except ITMY_UL or satalite box.

Gautam shows perfect form in the OMC chamber.

So if the SRM satellite box is good, than the ITMY sensor UL or vacuum cabeling from sersor to sat amp is bad.

Is the spare sat amp is bad ?

In the morning, Steve will start opening the north BS door so that we can enter to inspect the PRM LR OSEM.

For the ITMY, I squished together the cables which are in the 'Cable Interface Board' which lives in the rack. This thing takes the 64 pin IDC from the satellite module and converts it into 2 D-sub connectors to go to the PD whitening board and the coil driver board. Lets see if the ITMY OSEM glitches change character overnight.

We may lost the UL magnet or LED

I think if the magnet fell off, we would see high DC signal, and not 0 as we do now. I suspect satellite box or PD readout board/cabling. I am looking into this, tester box is connected to ITMY sat. box for now. I will restore the suspension later in the evening.

Suspension has now been restored. With combination of multimeter, octopus cable and tester box, the problem is consistent with being in the readout board in 1X5/1X6 or the cable routing the signals there from the sat. box.

• Tester box hooked up to sat box ---> UL coil still shows 0 in CDS.
• Tester box hooked up to sat box ---> Mon D-sub on sat box shows expected voltages on DMM. So tester box LEDs are being powered and seem to work.
• Sat box re-connected to test mass ---> Mon D-sub on sat box shows expected voltages on DMM. So OSEM LEDs are being powered and seem to work.
• Sat box remains connected to TM ---> Front panel LEMO monitor points on readout board shows 0 for UL channel, other channels are okay.

This bad connection is coming back

Steve and Koji (Friday, Apr 02)

Summary

Intsallation of ITMs are going on. Two new ITMs were placed on the optical table in the vacuum chambers. ITM for the south arm was put at the right place in accordance to the CAD drawing. ITM for the east arm is still at a temporaly place.

Tower placement (10:30-11:30)

- Put the tower on the table at a temporary place such that we can easily work on the OSEMs.

ITM (South arm) (14:00-16:30)

- Put the tower on the table at a temporary place such that we can easily work on the OSEMs.

- Leveled the table approximately.

- Released the EQ stops

- Removed anchors for the OSEM cables as it was too short. The wire distribution will be changed later.

- Put the OSEMs. Adjust the insertion to the middle of the OSEM ranges.

- Clamped the EQ stops again

- Placed the tower to the right place according to the CAD drawing.

- Released the EQ stops again.

- Check the OSEM values. The LL sensor showed small value (~0.5). Needs to be adjusted.

ITM (South) damping adjustment

- Found the signs for the facing magnets are reversed.

- Otherwise it damps very well.

Sitting down to start cavity measurements, I found both ITMs tripped.  It must have happened a while ago (I didn't bother to check dataviewer trends) because both had rms levels of <5 counts, so they've had a while to sit and quiet down.

Summary:

Steve and I tried to fix the Oplev situation detailed in elog 8684, today afternoon. We have come up with a fix which needs to be adjusted, possibly completely overhauled depending on whether the mirror steering the return beam to the QPD is blocking the POX beam coming out. 

Details:

• ITMx Oplev servo was first turned off.
• It turns out we were hitting the wrong pair of Oplev steering mirrors inside the chamber. The incident beam was hitting a mirror meant for IR light (see sketch below) and not the intended first steering mirror. We pretty much redid the entire alignment (we used a pair of irises initially to set up a reference path) so as to hit the right pair of mirrors inside the chamber. At the end of today's efforts, the beam is reasonably well centered on both the intended mirrors, and there is not as much scattered light. 

Situation in the chamber: the black line is meant to indicate what was happening, the red is indicative of the present path.

• The Oplev laser was installed in 2011 (October 13,2011 to be precise), and the quality of the beam coming out of the laser was pretty bad (the cross section was badly distorted even before it hit any optics). Steve thought this laser had reached the end of its lifetime, so we replaced the laser with a new one. Output power of this new laser has yet to be measured. The power-supply for the laser was also dodgy so we switched that out as well, and installed a new power supply. New laser and power supply are working satisfactorily. The old power supply will be checked with another laser tomorrow to gauge its status.
• The cross-section of the beam from the new Oplev laser was deemed satisfactorily circular and we centred it on the first of the two lenses in the beam-path. We are getting 2.81 mW of power from the new laser.
• In order to hit the right pair of Oplev steering mirrors while avoiding the clipping the beam on the tip-tilt/PR2 suspension, we had to sort of widen the angle of the beam going in, and so both steering mirrors, as well as the second lens in the beampath were shifted around. I have attached before and after pictures of the layout on the table. We adjusted things till the beam is reasonably well centred on both steering mirrors inside the chamber.
• Because of the changed beam-path, the return Oplev beampath also changed, and so we had to move the steering mirror directing the return beam to the QPD as well. In its new position, it may be clipping the POX beam.
• The beam is not getting clipped anywhere on the table now. It is also well centered on the two lenses in its path.
• We placed two irises marking the new path so that we have a reference if the alignment needs to be changed again.
• Turned ITMx Oplev servo back on.

Other stuff:

1. The higher--power new laser means that the QPD sum is now ~6000counts (up from ~3500). The power in the return beam is 143.5 uW, which is ~5% of the power of the input beam.
2. We centred the spot on the QPD, though when we excited ITM in yaw, the spot doesn't quite move horizontally, rather, it moves somewhat diagonally. 
3. I turned the lights off, blocked the beam and measured the zero-current counts for the various QPD quadrants. These were all less than 1.5, and I reset these values on the ITMx Oplev screen according to my measurements.
4. While viewing the spot of the Oplev beam on the ITMx face, we noticed that there were two spots, one less bright than the other. Steve suspects that this is because of multiple reflections from the chamber window.
5. The status of the POX beam has to be verified (i.e is it getting clipped by the steering mirror for the return beam?)
6. There was a Thorlabs PD on the table which had a green power LED. Jenne had asked me to cover this LED up, which I did with bits of tape.

Plan of action:

• The spot size at the QPD is right now about 3mm. We may want to improve this by moving the first of the two lenses in the beam-path (there is not a whole lot of room to maneuvering the second lens.
• Jenne just aligned and locked the X-arm, and doesn't think that the POX beam is being blocked, but I will verify this sometime tomorrow.

BEFORE

AFTER

 (Manasa)

The ITMx Oplev was misaligned. Switched the ITMx Oplev back on and fixed the alignment.

EDIT, JCD:  This is totally my fault, sorry.  I turned it off the other day when I was working on the POP layout, and forgot to turn the laser back on.  Also, I moved the fork on the lens directly in front of the laser (in order to accommodate one of the G&H mirrors), and I nudged that lens a bit, in both X and Y directions (although very minimally along the beam path).  Anyhow, bad Jenne for forgetting to elog this part of my work.

 [Jenne, Gautam]

It turned out that the earlier fix was not really a fix, because there was some confusion as to which of the two lenses Jenne moved while working, and while Manasa and I were re-aligning the beam, we may have moved the other lens.

Subsequently, when we checked the quadrant sum, it was low (in the region of 20), even though OPLEV_PERROR and OPLEV_YERROR were reasonably low. We called up a 30 day trend of the quadrant sum and found that it was typically closer to 4000. This warranted a visit to the table once again. Before going to the table, we did a preliminary check from the control room so as to make sure that the beam on the QPD was indeed the right one by exciting ITMx in pitch (we tried offsets of 500 and -500 counts, and the spot responded as it should). ITMx oplev servo was then switched off.

At the table, we traced the beam path from the laser and found, first, that the iris (I have marked it in one of the photos attached) was practically shut. Having rectified this, we found that the beam was getting clipped on the first steering mirror after the laser (also marked in the same photo, and a second photo showing the clipping is attached). The beam isn't very well centred on the first lens after the laser, which was the one disturbed in the first place. Nevertheless, the path of the entering beam seems alright. The proposed fix, then, is as follows;

1. Use the existing iris and a second one to mark the path of the entering beam.
2. Make the necessary adjustments (i.e. move the lens immediately after the laser and the first steering mirror after the laser) such that the direction of the entering beam is unchanged, and the clipping and centering problems are resolved. 

Back in the control room we noticed that the quadrant sum had gone up to ~3500 after opening out the iris. The OPLEV_PERROR and OPLEV_YERROR counts however were rather high (~200 counts in pitch and ~100 counts in yaw). Jenne went back to the table and fixed the alignment such that these counts were sub-10, and the quadrant sum went up to ~3800, close to the trend value. 

At the time of writing, the beam is still not centred on the lens immediately after the laser and is still getting clipped at the first steering mirror. Oplev servo back on.

Photos

 An overview

The clipping

 Jenne just aligned the X arm and I got a chance to check the status of the POX beam coming out of the chamber. Turned the Oplev servo off so that the red beam could be blocked, turned all the lights off, and had a look at the beam in the vicinity of the mirror steering the Oplev-out beam to the QPD with an IR view-card. The beam is right now about half a centimeter from the pitch knob of the said mirror, so its not getting clipped at the moment. But perhaps the offending mirror can be repositioned slightly, along with the Oplev QPD such that more clearance is given to the POX beam. I will work this out with Steve tomorrow morning. 

 With rana's input, I changed the ITMx oplev servo gains given the beam path had been changed. The pitch gain was changed from 36 to 30, while the yaw gain was changed from -25 to -40. Transfer function plots attached. The UGF is ~8Hz for pitch and ~7Hz for yaw.

I had to change the envelope amplitudes in the templates for both pitch and yaw to improve the coherence. Above 3Hz, I multiplied the template presets by 10, and below 3Hz, I multiplied these by 25.

 As mentioned in elog 8770, I wanted to give the POX beam a little more clearance from the pick-off mirror steering the outcoming oplev beam. I tweaked the position of this mirror a little this morning, re-centred the spot, and checked the loop transfer function once again. These were really close to those I measured last night (UGF for pitch ~8Hz, for yaw ~7Hz), reported in elog 8777, so I did not have to change the loop gains for either pitch or yaw. Plots attached.

At ~930am, I vented the IY annulus by opening VAEV. I checked the particle count, seemed within the guidelines to allow door opening so I went ahead and loosened the bolts on the ITMY chamber.

Chub and I took the heavy door off with the vertex crane at ~1015am, and put the light door on.

Diagnosis plan is mainly inspection for now: take pictures of all OSEM/magnet positionings. Once we analyze those, we can decide which OSEMs we want to adjust in the holders (if any). I shut down the ITMY and SRM watchdogs in anticipation of in-chamber work.

Not related to this work: Since the annuli aren't being pumped on, the pressure has been slowly rising over the week. The unopened annuli are still at <1 torr, and the PAN region is at ~2 mtorr.

We have calibrated the overall actuators of each suspension independent of the optical levers. So, we know how much we are 
moving the optic in POS in real units as a result of the dither we inject for the lockin measurement. The amount the oplev beam 
appears to move if there is only POS motion is
d/cos(theta)
where theta is the oplev's angle of incidence and d is the distance the optic has moved in POS.  None of the of the steering mirrors in the 
oplev path matter. 

I propose that I will add an option in the lockin path to subtract away the apparent angle from the oplev output just before the signal 
goes into the lockin module.  Then we will be balancing the actuators based on only the actual angular motion.

The success of this technique depends on how well we know our actuator calibration and the oplev angle of incidence. This also 
assumes that the oplev beam is centered on the optic, so we don't have beam displacement from A2L of the oplev beam, which then 
makes another apparent angular motion.  I suspect that we are close enough that we won't have to worry about this effect.

Koji asked me to look at what the ideal RF modulation frequency is, for just the PRMI case (no arms).  If we had a perfect interferometer, with the sidebands exactly antiresonant in the arms when the arms resonate with the carrier, this wouldn't be an issue.  However, due to vacuum envelope constraints, we do not have perfect antiresonance of the sidebands in the arm cavities.  Rather, the sideband frequencies (and arm lengths) were chosen such that they pick up a minimum amount of extra phase on reflection from the arms.  But, when the arms are off resonance (ex, the ETMs are misaligned), the sideband frequencies see a different amount of phase.   

We want to know what a rough guess (since we don't have a precise number for the length of the PRC since our last vent) is for the ideal RF modulation frequency in just the PRMI. 

If I take (from Manasa's kind measurements from the CAD drawing yesterday) the relevant distances to be:

L_P[meters] = 1.9045 + 2.1155 + 0.4067

L_X[meters] = 2.3070 + 0.0254*n

L_Y[meters] = 2.2372 + 0.0359*n + 0.0254*n

L_PRCL = L_P + (L_X + L_Y)/2 = 6.7616 meters.

The *n factors (n=1.44963) are due to travel through glass of the BS, and the substrate of the ITMs. 

I find the FSR of the PRC to be 22.1686 MHz. For the sidebands to be antiresonant, we want them to be 11.0843 MHz. This would correspond to a mode cleaner length of 27.0466 meters.  Our current modulation frequency of 11.066134 MHz corresponds to a MC length of 27.091 meters.  So, if we want to use this 'ideal' modulation frequency for the PRC, we need to shorten the mode cleaner by 4.4cm!  That's kind of a lot.

To change the MC length is not the point.

If we can improve the length sensing by the intentional shift of the modulation frequency from the MC FSR, that's worth to try, I thought.

But that is tough as the freq difference is 18kHz that is ~x4 of the line width of the MC.
Not only the 55MHz sidebands, but also the 11MHz sidebands will just be rejected.

Nevertheless: Is there any possibility that we can improve anything by shifting the modulation frequency by ~1kHz?

JA - MIE - RO!

1/4" exposure, standard room lights                                                                              3" exposure, slowly moving LED bar light from ~60 cm distance

Note:
Because of the light behind, the focus was attracted by the far objects...
Evenso the magnet ball looks better in the right picture.

The technique is as follows:
Use longer exposure time, move the LED bar illumination through the area like painting the light everywhere.
It is supposed to provide a picture with more uniform light and the diminished shadow.

(KA)

- Use LEDs of a wavelength that the OSEMs don't see. LEDs are also cool so that the
  Suspension won't drift in alignment.

- Use 2 power supplies so that the power is balanced.

- Make is +/-12 V twisted AWG 14 wire so that the EMI is contained. Should also
  be shielded cable.

I acquired 2 raw frames of MC2 using "/users/mjenson/sensoray/sdk_2253_1.2.2_linux/capture -n -s 720x480 -f 1", one while the laser was off the mode cleaner and another while it was on:

I then used "/users/mjenson/sensoray/sdk_2253_1.2.2_linux/imsub/display-image.py" to generate bitmaps of the raw images, which I then subtracted using the Python Imaging Library to generate a new image:

It doesn't look all that different, but the first image didn't have that much lit up in it to begin with. I should be able to write a script that does all of this without needing to generate new files in between acquisition and subtraction.

 This is totally cool!  You can see that the OSEM lights are almost entirely gone in the subtracted image.

Can you switch to trying with one of the *TM*F cameras?  (ITMXF, ITMYF, ETMYF, ETMXF)  They tend to have more background, so there should be a more dramatic subtraction.  Den or Suresh should be able to lock one of the arms for you.

On Friday, Koji helped me find various components required for the scatterometer setup. Like he suggested, I'll first set it up on the SP table and try it out with an usual mirror. Later on, once I know it's working, I'll move the setup to the flow bench near the south arm and measure the BRDF of a spare end test mass.

I borrowed the HP impedance test kit from Rich Abbott today. The purpose is to profile the impedance of the NPRO PZTs, as part of the AUX PDH servo investigations. It is presently at the X-end. I will do the test in the coming days.
 

The nominal gain of the XARM for the POX11 error signal is 0.03 (instead of previous 0.3)

This is due to my increase of the gain in FM4 by 20dB so that we can turn of FM4 without changing the UGF when it is at 150Hz.

The YARM servo was not yet touched.

Duncan Macleod (original author of summary pages) has an updated version that I would like to import and work on.  The code and installation instructions are found below.

I am not sure where we want to host this.  I could put it in a new folder in /users/public_html/  on megatron, for example.  Duncan appears to have just included the summary page code in the pylal repository.  Should I reimport the whole repository?  I'm not sure if this will mess up other things on megatron that use pylal.  I am working on talking to Rana and Jamie to see what is best.

http://www.lsc-group.phys.uwm.edu/cgit/lalsuite/tree/pylal/bin/pylal_summary_page
https://www.lsc-group.phys.uwm.edu/daswg/docs/howto/lal-install.html

I am following the instructions here:

https://www.lsc-group.phys.uwm.edu/daswg/docs/howto/lal-install.html#test

But there as an error when I run the ./00boot command near the beginning.  I have asked Duncan Macleod about this and am waiting to hear back.

For now, I am putting things into /home/controls on allegra.  My understanding is that this is not shared, so I don't have a chance of messing up anyone else's work.  I have been moving slow and being extra cautious about what I do because I don't want to accidentally nuke anything.

 I installed the new version of LAL on allegra.  I don't think it has interfered with the existing version, but if anyone has problems, let me know.  The old version on allegra was 6.9.1, but the new code uses 6.10.0.1.  To use it, add . /opt/lscsoft/lal/etc/lal-user-ench.sh to the end of the .bashrc file (this is the simplest way, since it will automatically pull the new version).

I am having a little trouble getting some other unmet dependencies for the summary pages such as the new lalframe, etc.  But I am working on it.

Once I get it working on allegra and know that I can get it without messing up current versions of lal, I will do this again on megatron so I can test and edit the new version of the summary pages.

 LALFrame was successfully installed.  Allegra had unmet dependencies with some of the library tools.  I tried to install LALMetaIO, but there were unmet dependencies with other LSC software.  After updating the LSC software, the problem has persisted.  I will try some more, and ask Duncan if I'm not successful.

Installing these packages is rather time consuming, it would be nice if there was a way to do it all at once.