I had to change the c1ioo model and restart the fb since the paths allowing us to select various signals to demodulate using the lockins were not correct. The signal selection vector was not flexible enough to permit us to select the signals to demod.
fb was restarted twice at following times. The changes have been commited to the svn.
Fri Sep 16 13:35:47 PDT 2011
Fri Sep 16 14:36:21 PDT 2011
Paul, Mirko and Katrin visiting grad students received the 40m basic safety training.
New f2a filters were installed on SRM.
The lock of DRMI should be more stable than last night.
Once the SRM oplev project settles down, I will adjust the f2a filters on SRM too.
I've calculated a suitable collimating telescope for the ITMY/SRM oplev laser, based on the specs for the soon-to-arrive 2mW laser (model 1122/P) available here: http://www.jdsu.com/ProductLiterature/hnlh1100_ds_cl_ae.pdf
Based on the fact that the 'beam size' value and 'divergence angle' value quoted don't match up, I am assuming that the beam radius value of 315um is _not_ the waist size value, but rather the beam size at the output coupler. From the divergence angle I calculated a 155um waist, (zR = 12cm). This gives the quoted beam size of about 316um at a distance of 8.5" away from the waist. This makes me think that the output coupler is curved and the waist is at the back of the laser, or at least 8.5" from the output coupler.
The collimating telescope gives a waist of size 1142um (zR=6.47m) at a distance of 1.427m away from the original laser waist, using the following lens combo:
L1 f=-0.15 @ 0.301m
L2 f=0.3 @ 0.409m
This should be fine to get a small enough spot size (1-2mm) on the QPDs.
I just drew a basic picture of how the ITMX oplev path could be reworked to minimise the number of optics in the path. Only possible problem with this might be the turning mirror onto the ITMX getting in the way of the collimating lenses. Should be easy to solve though. Does anyone know if there is a ITMX pick off beam I should be careful to avoid?
I put the new matricies in from the free swinging test for the: ITMX, ITMY, ETMX, ETMY, PRM, BS
Some of the optics damped okay, but ETMX and BS were not good at all. ETMX was ringing up when I turned on the damping. BS wasn't, but when I gave it a kick, it wouldn't damp. No good.
I tried ITMY, and it was totally fine, with nice damping Qs of ~5. So, I don't know what's going on.
Anamaria is trying a new 4x4 matrix-inverter, so we can look at the inversion of just the face osems. We'll see how it goes.
Since things were crappy, I did a BURT restore, so things are as they were earlier this morning.
The bad medm screens have been fixed. There are no blank fields and all the links are correct.
I've found that a few of the screens still have Whited-Out fields due to naming changes (OL SUM and ALS-> TM OFFSET). I attach a screen shot of it.
The OL screens have the wrong SUM names and the IFO ALIGN screen is pointing to the wrong SUS screens.
The demodulation phases and gains for the all existing channels, AS11, REFL11,REFL55, REFL165, and REFL33, were adjusted by the command "ezcawrite" commands.
REFL165 ezcawrite C1:LSC-REFL165_Q_GAIN 0.934340 && ezcawrite C1:LSC-REFL165_PHASE_D -81.802479
ezcawrite C1:LSC-REFL33_Q_GAIN 0.984244 && ezcawrite C1:LSC-REFL33_PHASE_D -89.618
New channels, POP55 and POY11 are connected to the rack and now available on the data system.
POX11 I is not working. I didn't investigate what was wrong. Please make sure when you come to need POX11.
The orthogonalities of POY11 and POP55 were measured and already adjusted. The results are below:
ABS = 0.973633
PHASE = 92.086483 [deg]
ezcawrite C1:LSC-POY11_Q_GAIN 1.027081 && ezcawrite C1:LSC-POY11_PHASE_D 92.086483
ABS = 1.02680579
PHASE = 88.5246 [deg]
ezcawrite C1:LSC-POP55_Q_GAIN 0.973894 && ezcawrite C1:LSC-POP55_PHASE_D 88.524609
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.
In order to estimate the amount of noise that the oplevs are injecting into the GW channel, we first need to calibrate oplev signals in terms of angular change in the optic. I said in my previous post that there wasn't a calibration factor for OSEM values to radians, but I found that Kakeru had estimated this in 2009 - see entry 1413. However, Kakeru found that this was quite a rough estimate, and that it didn't agree with his calibrated oplev values well. He does quote the 2V/mm calibration factor for the OSEM readings though - does anyone know the provenance of this factor? I searched for OSEM calibration and found nothing.
With the new input matrix, it looks like YAW and SIDE are not quite decoupled on ETMX.
It needs one more kick and free swinging test.
- - - details
To see what exactly is going on, I changed the input matrix from the default to the new one, which Jenne computed (#5421) on ETMX.
I started putting the elements of the input matrix from POS through SIDE, one by one.
It seemed that POS and PIT worked fine. However the YAW signal looks containing a lot of the SIDE signal.
Similar to YAW, SIDE also interact with the YAW motion and somehow rings up both YAW and SIDE signals as Jenne reported ( #5438).
So right now the YAW and SIDE rows are partially reburted to the default elements in order to avoid ringing up.
but ETMX and BS were not good at all. ETMX was ringing up when I turned on the damping.
Keiko, Paul, Kiwamu
We found that POP beam is clipped by the steering mirrors inside the tank. POY beam is also likely to be clipped inside. Also the hight of POY beam is too high (about 5 cm higher than the normal paths) at the first lens. These imply the input pointing is bad.
Excited all the optics. They will be automatically back after 5 hours.
Sat Sep 17 02:02:07 PDT 2011
The PZT driver is now in place. The actual PZTs are not connected yet!
It is accommodated on Ben's connector adapter board.
The panel has additional connectors now: two inputs and a power supply connector.
The supply voltage is +/-30V (actual maximum +/-40V), and the input range is +/-10V
which yields the output range of -5V to 30V. The gain of the amplifier is +2.
It is confirmed that the HV outputs react to the epics sliders although the PZT connector is not connected yet
so as not to disturb the locking activity.
When we engage the PZT connector, we should check the HV outputs with an oscilloscope to confirm they
have no oscillation with the capacitances of the PZTs together with the long cable.
We don't need a high quality calibration for the optical levers. ~50% accuracy is fine.
For that you can use the OSEM calibration of ~1.7 V/mm (its less than 2 since the OSEMs have been degrading) or you can use the cavity power method that Kakeru used; it worked just fine. There's no benefit in trying for a 1% number for optical levers.
This modification of the LSC model made the rows of the LSC output matrix shifted. This caused the ASS scripts nonfunctional.
Kiwamu fixed the channel names in the ASS script.
[Jenne, Mirko, with supervision from Jamie]
I modified the c1lsc model to have shmem outputs that go from the degrees of freedom to the OAF, and shmem inputs from the OAF's output to sum into the DoFs, just like Yoichi's FF stuff. I also removed the old OAF_OUT, because it would only allow me to select one DoF at a time, and I will eventually want the ability to do multiple amounts of OAFing at the same time. Hopefully.
The pzt driver for PZT1 has been installed.
As there was unknown resistive connection in the vacuum chamber as described below,
the PZT out cable at the PJ driver module should always be disconnected.
The sensor cables have no problem to be connected to the controller.
In fact, they are a good monitor for the state of the PZTs.
In this configuration, Pitch and Yaw direction of PZT1 is under the control of the EPICS value as we expected.
- At the beginning, we tested the PZT driver output with low voltage level (~10V). We did not see any oscillation of the opamps.
The pitch output was observed to be OK, while the YAW output exhibited a half of the expected output voltage.
The opamp was holding correct voltage, however the voltage after the 1K output resister was about a half.
This indicated there was a voltage division happening.
- The cause of the voltage division was tracked. We found that the yaw red (=hot) line is connected to pitch black
in the vacuum chamber with a resistance of 1.4kOhm. The black cables are shorted to the ground level in the PJ driver.
- We decided to unplug the PJ's cable so that we can isolate the black cables while hoping the PZTs were drived only
by the red and white cables. And they did.
- This means that we should not connect the PZT driving cable to the PJ's driver. The sensors have no problem to be connected.
|. o| 5
|o | 17
| o| 4
|o | 16 Yaw Black
| o| 3 Pitch Black
|o | 15 Yaw White
| o| 2 Yaw Red
|o | 14 Pitch White
\ o| 1 Pitch Red
* Pitch White and Yaw White are connected to the ground at the amplifier side.
* Yaw Red and Pitch Black is connected with 1.4kOhm and isolated from the others.
The f2a filters were installed on ITMs and ETMX.
Now all of the suspensions has the f2a filters.
[Anamaria / Kiwamu]
The incident beam pointing was improved by using PZT1 and PZT2.
With some triggers the lock of PRMI became smoother.
For the DRMI lock, the MICH and SRCL signals on AS55 are not quite decoupled, so we should find cleaner signals for them.
(what we did)
+ locked the Y arm
+ aligned incident beam by using PZT1(#5450) and PZT2. The spot positions on ITMY and ETMY are now well-centered.
+ tried activating C1ASS but failed. It needs some gain changes due to the new PZT1 response.
+ locked the X arm
+ aligned the TRX PD (Thorlab signal PD) and set the trigger.
+ C1ASS also doesn't work for the X arm
+ realigned the PRM and BS oplevs. the PRM oplev was clipped at a steering mirror on the optical bench
+ locked PRMI and aligned the PRM mirror such that the optical gain was maximized
+ optimized the demod phase of AS55 and REFL11
+ checked the UGF of the MICH and PRCL lock. The UGF of MICH is about 100Hz with gain of -20, and the UGF of PRCL was 85 Hz with gain of 0.1
+ adjusted the output matrix such that the MICH control doesn't couple into the PRCL control.
+ set the triggers for the MICH and PRCL control to make the lock acquisition smoother.
+ tried locking DRMI and it was sort of locked. However the SRCL signal showed up a lot in AS55_Q, where the MICH signal is extracted.
Actually the clipping of POP wasn't in the chamber but it was on the first lens on the optical bench.
So I repositioned the lens to avoid the clipping and now there are no clipping on POP.
We found that POP beam is clipped by the steering mirrors inside the tank.
I replaced the lenses that were there with a -150mm lens followed by a +250mm lens. This gave a significantly reduced beam size at the QPDs. With the beam analyzer up and running it should be possible to optimize this later this afternoon. Next I will remove the SRM QPD from the path and make measurements of the beam spot position movement and corresponding OSEM values for different DC mirror offsets. I will then repeat the process for ITMY.
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).
I made the first measurements towards oplev calibration measurements: calibrating the oplevs in SRM YAW. The measurements seemed fine, I had a range of between -1.5 and 1.5 in SRM DC alignment before clipping on mirrors on the oplev bench became a problem. This seemed to be plenty to get a decent fit for the spot position against DC alignment value - see attached plot. The fitted gradient was -420um oplev yaw count. I calculated oplev yaw values as UL+LL-UR-LR. Pitch next.
The following optics were kicked:
Mon Sep 19 15:39:44 PDT 2011
Earlier measurements of the modulation index were less than optimal because we had too low transmission through the cavity. Contrary to what was believed you actually need to modematch onto the cavity.
Earlier transmitted power was about 8.5uW.
With a 250mm lens we archived 41uW.
Impinging power on the cavity is 1.7mW.
PD TF approx 0.1V / uW.
Carrier power: 4.1V => 41uW
41uW/1.7mW = 2.4 % transmission. Manufacturer clain for peak transmission: 20-30%.
11MHz SB: 28.8mV => m=0.17
55MHz SB:36mV => m=0.19
As you can see on the pic the SNR of the SBs is not too good.
The gain of whitening filters on AS55 was decreased from 21 dB to 0 dB for the Y arm locking.
- - (Background)- -
Since the modulation depths became bigger from the past (#5462), the PDH signal from Y arm was saturated in the path of AS55.
Due to the saturation the lock of the Y arm became quite difficult so I decreased the gain of of the whitening filter from 21 dB to 0 dB.
In this condition, a required gain in C1:LSC-YARM_GAIN is about -0.3, which is 10 times bigger from the default number.
For the MICH locking tonight, it may need to be back to a big gain.
Same measurements for SRM pitch (as previously done for yaw in entry 5460) are complete. The QPD is back in the path and aligned. I will be doing the same measurements for ITMY now though, so please ask before activating the SRM or ITMY oplev servos, as I may be blocking the beam.
Kiwamu: The bad medm screens have been fixed. There are no blank fields and all the links are correct.
Really? I found this one with ~15 seconds of clicking around.
I changed some colors on the Summary of Suspension Sensor using my italian creativity.
I wrote a script in Python to change the thresholds for the "alarm mode" of the screen.
I've started to fix up the script somewhat (as a way to teach myself some more python):
* moved all of the SUS Summary screen scripts into SUS/SUS_SUMMARY/
* removed the hardcoded channel names (a list of 190 hand-typed names !!!!!!!)
* fixed it to use NDS2 instead of try to use the NDS2 protocol on fb:8088 (which is an NDS1 only machine)
* it was trying to set alarms for the SUS gains, WDs, Vmons, etc. using the same logic as the OSEM PD values. This is non-sensical. We'll need to make a different logic for each type of channel.
New script is called setSensors.py. There are also different scripts for each of the different kinds of fields (gains, sensors, vmons, etc.)
pianosa:SUS_SUMMARY 0> ./setDogs.py 3 5
Done writing new values.
Another Hamasutu S3399 photodiode was tested with the electronic circuit as described in LIGO-D-1002969-v.
RF transimpedance is 1k although the DC transimpedance is 2k.
The noise level is 25pA/sqrt(Hz) which corresponds to a dark current of 1.9mA or 1.7mA in the independent measurement.
At all frequencies the noise is larger compared to Koji's measurement (see labbook page 4778).
In file idet_S3399.pdf the first point is not within its error bars on the fitted curved. This point corresponds to the dark noise measurement
I made this measurement again. Now it is on the fitted curve. In the previous measurement I pushed the save button a bit too early. The
averaging process has not been ready while I pushed the 'save' button.
Dark current is 1.05mA and noise is lower than in the previous measurement.
New file are the XXX_v2.pdf files
The last person out tonight should run the following scripts:
In command line:
Then in the morning, someone should do a BURT restore to early today (to get the default matricies back), and also restore the watchdogs.
We started to investigate the AM modulation mistery again. Checking just after the EOM, there are AM modulation about -45dBm. Even if we adjust the HWP just before the EOM, AM components grow up in 5 mins. This is the same situation as before. Only the difference from before is that we don't have PBS and HWP between the EOM and the monitor PD. So we have a simpler setup this time.
We will try to align the pockells cell alignment tomorrow daytime, as it may be a problem when the crystal and the beam are not well parallel. This adjustment has been done before and it didn't improve AM level at that time.
I have made some cleaning up of the LSC-related MEDM screens.
- LSC overview screen: ADC OVFL and WFAA indicators are now correctly matched to it associated PD signals.
- Whitening screens now have the correct indication of the associated PD signals.
- LSC Ctrl screen, which is invoked from the overview screen by clicking the servo filters, now has the switches of the servo filters.
- LSC tab of the sitemap was cleaned up by removing the broken links.
Keiko, Anamaria, Koji
We were not able to establish the stable DRMI tonight. We could lock MICH and PRCL quite OK, and lock the three degrees of freedom at somewhere strange for several seconds quite easily, but the proper DRMI lock was not obtained.
When MICH and PRC are locked to the carrier, REFL DC PD reading dropps from ~3000 counts to 2600~2700 counts as REFL beam is absorbed to PRC. We'll try to lock PRC to sidebands - but flipping gain sign didn't work today, although it worked a few days ago.
POP beam (monitor) is useful to align PRM.
I followed Jenne's instructions, ran the matrix filler script and then set the optics to freeswing. Someone has to burt resture and damp them in the morning.
Thanks! I'll give them a little more time, then restore things.
I began restoring the optics at ~9:30am, so I have a full 6 hours of data, in case I need that much to separate the Pos/Side modes on some of the optics. They are all damping again with their original matricies.
Since the MC wasn't able to capture the 00 mode in this morning I aligned the incident beam going to MC.
As a result C1:IOO-RFPD_DCMON went down to 0.6. However the beam on IPPOS is almost falling off from the QPD.
So, clearly this was a kind of dumb idea. There is nothing mechanical going on between our sensor inputs and our Pit/Pos/Yaw/Side DoF filter banks. It's just math. On the other hand, we now have a 3rd set of in-vac free swinging data, so I can (after all the suspensions are working) have a look at the drift in matrix elements over time.
In other news, after some meditation, and fitzing with DoF gain values, all of the IFO optics except for SRM now have their new input matricies, and are damping pretty nicely. I need to go through and do an "eyeball" check to make sure that everything has a Q of ~5ish. So far, I've kicked the optics, and watched that they damped fairly quickly, but I don't have a guesstimate of the Q's for each optic, for each DoF.
So, still to do:
Use another set of data and invert the SRM matrix DONE
Plug in the MC matricies, make sure they're okay. DONE
Check the Q's for all optics, all DoFs.
This is using data for the SRM from: 20 Sept 2011 03:20:00 PDT = 1000549215
You can see that there are still some funny peaks between Pit and Yaw, but I finnessed the peak-finding, and I was able to fit all of the correct peaks, and invert the matrix:
SRM now has its new matrix, and is damping happily.
pit yaw pos side butt
UL 0.877 0.983 1.105 -0.288 1.092
UR 1.010 -1.017 1.123 -0.145 -1.055
LR -0.990 -1.002 0.895 -0.091 0.848
LL -1.123 0.998 0.877 -0.234 -1.006
SD 0.089 0.064 3.752 1.000 -0.009
Can't we use Yuta's auto-Q adjust script?
Edit by KI :
Of course we can use it but first we have to fix some pynds sentences since his script was written for the OLD pynds.
[Suresh / Kiwamu]
The MC REFL camera is now available. The camera name is "MCR" and you can call it from the videoswitch script.
+ repositioned and aligned the MCR camera.
+ checked the MCR camera.
=> found the camera view shows a negative image (i.e. the beam spot is dark and the background is bright !!)
+ replaced the camera by a spare one.
+ modified the videoswitch script because the input channel 3 was wrongly assigned to MCR.
MCR was correctly assigned to the input channel 18.
Modulation resonator box is removed and the modulation depth is small right now.
I have broke the BNC connector on the modulation resonator box. The connector was attached by the screw inside very loosely and when we connect and disconnect the BNC cables from outside, extra force was applied to the cable inside and it was broke. It is being fix by Kiwamu and will be back in a bit.
Resonator box and the modulations are back now. But the modulation depth seems to be a bit smaller than yesterday, looking at the optical spectrum analyser.
I have broke the BNC connector on the modulation resonator box. The connector was attached by the screw inside very loosely and when we connect and disconnect the BNC cables from outside, extra force was applied to the cable inside and it was broke. It is being fix by Kiwamu and will be back in a bit
Has the Q been checked? Still in progress...
So, update as of 6:17pm: I have tuned the damping gains for all IFO optics. Everything is good, except for ITMY Yaw. It's probably fine, the optic damps okay, but it doesn't look like a nice clean ringdown. I haven't taken the time to go back and look at it again.
I have to go to a dinner, but later (probably in the morning, so I don't disturb evening locking) I'll check the MC Qs.
[Jenne / Kiwamu]
Fb was sick. Dataviewer and Fourier Tools didn't work for a while.
After 10 minutes later they became healthy again. No idea what exactly was going on.
One thing we found was that : during the sickness of fb, it looks like daqd was restarting by hisself. Is this normal ??
Here is the bottom sentences of restart.log. Apparently daqd was rebooting although we didn't command to do so.
daqd_start Tue Sep 20 02:41:17 PDT 2011
daqd_start Tue Sep 20 13:18:12 PDT 2011
daqd_start Tue Sep 20 17:33:00 PDT 2011
The measured calibration factors for the oplevs are as follows:
Kiwamu noticed that the 1/L in the counts per radian should have just been L, which accounts for most of the discrepancy. We checked the input filters on the OSEMs, and they have 10dB of gain at DC. Accounting for this, estimates on the order of 20urad/count, which is much more reasonable!
This morning after Kiwamu maximised the PSL beam coupling into the MC we noticed that the MC2 face camera showed the spot position had moved away from the center by about a diameter. So I checked the beam spot positions with MCASS and indeed found that the spot on MC2 had moved to about 6mm away from the center in yaw and about 3mm in pitch. I adjusted the MC2 (and only MC2) to recenter the spots on all the three mirrors. The new spot positions are given below
spot positions in mm (MC1,2,3 pit MC1,2,3 yaw):
1.3337 -0.2660 0.6641 -1.0973 0.0468 -1.7130
The PSL beam into MC has been readjusted for maximal coupling into MC.