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.
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 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.
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.
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.
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
I've now taken data for the pitch and yaw calibrations for the OSEMs of SRM and ITMY. Until such time as I know what the calibrated oplev noise spectra are like, I'm leaving the servo gains at zero.
I estimate the length of the lever arm from SRM to measurement position to be 3.06m, and the length of the lever arm from the ITMY to the measurement position to be 3.13m.
From the fits shown on the attached plots, this gives the following calibration factors for the SRM and ITMY OSEMs pitch and yaw counts (i.e. counts from channels such as SUS-ITMY_ULSEN_SW2 multiplied by a matrix of 1s and -1s) to pitch and yaw angle:
SRM PITCH: 1 OSEMs pitch count = 11.74 microradians
SRM YAW: 1 OSEMs yaw count = 12.73 microradians
ITMY PITCH: 1 OSEMs pitch count = 13.18 microradians
ITMY YAW: 1 OSEMs yaw count = 13.52 microradians
Next step is to do some DC offsets with the oplev paths back in place to get the final calibration between OSEMs counts and oplev counts, thus finally getting a conversion factor from oplev counts to radians.
I noticed while taking these measurements that the DC offsets I put on ITMY caused around 5 times larger change in angle than those on the SRM. The different path length is not enough to account for this, so I propose that the actuation is working differently for the two. I guess this should be taken into account when designing the output matrices (unless the control is passed through a different output matrix than the DC offsets?). I'll quantify the difference shortly, and write a conversion factor between output alignment count (e.g. SUS-ITMY_PIT_COMM) and angle.
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.
Kiwamu: 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.
Really? I found this one with ~15 seconds of clicking around.
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.
Here I note the procedure for the demodulation board orthogonality check for the future reference.
1. prepare two function generators and make sure I an Q demodulation signals go to the data acquisition system.
2. sync the two generators
3. drive the function generator at the modulation frequency and connect to the LO input on the demod board
4. drive the other function generator at the modulation frequency + 50Hz the RF in
5. run "orthogonality.py" from a control computer scripts/demphase directory. It returns the amplitude and phase information for I and Q signals. If necessary, compensate the amplitude and phase by the command that "orthogonality.py" returns.
If you want to check in the frequency domain (optional):
1. 2. 3 are the same as above.
4. drive the function generator at the LO frequency + sweep the frequency, for example from 1Hz to 1kHz, 50ms sweep time. You can do it by the function generator carrier frequency sweep option.
5. While sweeping the LO frequency, run "orthogonality.py"
6. The resulting plot from "orthogonality.py" will show the transfer function from the RF to demodulated signal. The data is saved in "dataout.txt" in the same directory.
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.
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 following optics were kicked:
Mon Sep 19 15:39:44 PDT 2011
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.
IPPOS is back. A cable had been disconnected at the 1Y2 rack. So I put it back to place.
The cartoon below shows the current wiring diagram. I think this configuration is exactly the same as it it used to be.
+ Fixing IPPOS (volunteers)
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 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.
+ Inversion and installation of the SUS input matrices (Jenne)
It turns out that this is complicated, since there are so many people working with the IFO this week. What I would like to do is put in the new input matricies, and then do a free swinging test, to see if the suspensions are really diagonalized in the way that we want them to be. I can't do this during the day, since it will interfere with Paul's OpLev work. And at "night", I can't, since we'll be doing locking. So, this may be a late-night task. I'll write a script this afternoon that will put in all of the new input matricies, and then run the freeswing and the restore watchdogs scripts. Whomever is the last one to leave for the night can run the combo script.
EDIT: As of this time (~11:45am), ITMY has its new input matrix.
GOAL1: Stable lock of DRMI
GOAL2: Measurement of the LSC input matrix in the DRMI configuration
/- - Daytime works - - /
+ Measurement of the arm lengths (Jenne / Kiwamu / volunteers)
+ Optimization of the oplev control loops (Paul)
+ Tuning of the SUS damping gains (Steve)
+ Measurement of the modulation depths (Mirko)
+ Preparation of the green broadband PD (Katrin)
+ Fixing the Y arm green lock servo (Katrin / Kiwamu)
+ Installation of RFPDs (Anamaria)
+ Minimization of the AM sidebands (Anamaria / Keiko)
+ Preparation of a script for measuring the LSC input matrix (Keiko)
+ MC WFS (Suresh)
+ Online adaptive filtering (Mirko / Jenne)
+ Modification of C1ASS (Kiwamu)
+ Auto alignment of PRCL and SRCL (volunteers)
+ Loss measurement of the arm cavities (volunteers)
+ Fixing the ETMX SIDE slow monitor (volunteers)
/- - Nighttime works - - /
+ Locking of DRMI
+ Characterization of DRMI and complete the wiki page
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.
[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.
The f2a filters were installed on ITMs and ETMX.
Now all of the suspensions has the f2a filters.
Mess in the lab is increasing. Kiwamu and I had to clean up some stuffs to continue our work.
(i.e. some components were disturbing to open the lid of the tables.)
Basically the tools/equipments/component/cables/digital cameras/lens caps/IR viewers
you have used for the day should be cleaned up at the end of the day.
If one likes to leave a temporary stuff, leave a note to indicate by whom, for what, how long
it will be kept like that, and when one is going to back there with contact info like the cell phone #.
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.
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.
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.
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.
Excited all the optics. They will be automatically back after 5 hours.
Sat Sep 17 02:02:07 PDT 2011
It needs one more kick and free swinging test.
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.
With the new input matrix, it looks like YAW and SIDE are not quite decoupled on ETMX.
- - - 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.
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.
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.
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
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
The bad medm screens have been fixed. There are no blank fields and all the links are correct.
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.
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'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.
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.
Paul, Mirko and Katrin visiting grad students received the 40m basic safety training.
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
I checked the dark and bright noise of the SRM oplev QPD. The SRM QPD has a rather high dark level for SUM of 478 counts. The dark noise for the SRM QPD looked a little high in the plot against the bright noise (see first attachment), so I plotted the dark noise with the ITMY QPD dark noise (see second attachment). It seems that the SRM QPD has a much higher dark noise level than the ITMY! In case anyone is wondering, to make these traces I record the data from the pitch and yaw test points, then multiply by the SUM (to correct for the fact that the test point signal has already been divided by SUM). I will check the individual quadrants of the SRM QPD to see if one in particular is very noisy. If so, we/I should probably fix it.
- We have checked the situation of the broken Piezo Jenna PZT (called PZT1)
- Tested PZT1 by applying a dc voltage on the cables. Found that pitch and yaw reasonably moving and the motions are well separated each other.
The pitch requires +20V to set the IPPOS spot on the QPD center.
- Made a high-voltage (actually middle voltage) amp to convert +/-10V EPICS control signal into -5 to +30V PZTout. It is working on the prototype board and will be put into the actual setup soon.
- The Piezo Jenna driver box has 4 modules. From the left-hand side, the HV module, Yaw controller, Pitch controller, and Ben abbot's connector converter.
- We checked the voltage on Ben's converter board. (Photo1)
It turned out that the red cable is the one have the driving voltage while the others stays zero.
- We hooked a 30V DC power supply between the red cable and the shield which is actually connected to the board ground.
- Applying +/-10V, we confirmed the strain gauge is reacting. If we actuated the pitch cable, we only saw the pitch strain gauge reacted. Same situation for yaw too.
- Kiwamu went to IPPOS QPD to see the spot position, while I change the voltage. We found that applying +20V to the pitch cable aligns the spot on the QPD center.
- I started to make a small amplifier boards which converts +/-10V EPICS signals into -5V to +30V PZT outs.
- The OPAMP is OPA452 which can deal with the supply voltages upto +/-40V. We will supply +/-30V. The noninerting amp has the gain of +2.
- It uses a 15V zener diode to produce -15V reference voltage from -30V. This results the output voltage swing from -5V to +35V.
The actual maximum output is +30V because of the supply voltage.
- On the circut test bench, I have applied +/-5V sinusoidal to the input and successfully obtained +5V to +25V swing.
- The board will be put on Ben's board today.
Kiwamu, Keiko, Anamaria
I started today with a different input beam, so I had to realign the REFL path again. Then we measured the RF signal out of the 4 REFL PDs and found them to be too low. We increased the power to around 10mA for each diode, and we can see the right modulation frequency on each diode, though REFL165 is way too weak so we might need an RF amplifier on it. We will measure demod board noise tomorrow.
We had an issue with REFL165 not giving the right DC level, low by a factor of 10, even though it was receiving the same optical power as the others. We fifteen-checked clipping and alignment, then pulled it out and measured it on the test stand - found it to be ok. So I uplugged its power cable at the rack and connected it to the AS165 slot. Problem sloved. Not sure what was wrong with the other power slot.
Then we found REFL55 to be clipping on its black glass, we fixed that. But the REFL55 DC power still changes a lot with seemingly not huge motions of the PRM. We'll investigate more tomorrow.
We added a lens in the path to REFL165 because unlike the others it is a 1mm diode. All diodes have about half a turn to a full turn flatness of maximum (on tiny steering mirror).
We set the whitening gain on all four diodes to 21 db.
Not sure if we should set the power to be different on these diodes since their sensitivity is different to RF, and now REFL11 sees huge signal.
We continued the DRMI locking attempt and brought in the SRC, using AS55I to control it. It kind of works/stays locked. We did manage to get MICH and PRC better controlled than last night, but with SRC in the mix, something is wrong. We have to redo f2a filters on SRM and hopefully things will be better after Jenne's suspension work tomorrow. Oplevs not optimized yet either.
We intend to realign POY beam path so we can monitor power in cavities.
I tried again at plotting the ITMY_QPD noise spectra in for dark and bright operation. Before we had the strange situation where the dark noise seemed higher, but Kiwamu noticed this was caused by dividing by the SUM before the testpoint I was looking at. This time I tried just multiplying by the measured SUM for bright and dark to normalise the spectra against each other. The results looks more reasonable now, the dark noise is lower than the bright noise for a start! However, the dark noise spectrum now doesn't look the same as the one I showed in my previous post.
The script takes a GPS-format start time as the 1st argument and a duration time as the second argument.
For every channel shown in the screen, it compute the mean value during this time.
The 3rd argument is the ratio between the mean and the LOW threshold. The 4th argument is the ratio between the mean and the LOLO threshold.
Then it sets the thresholds simmetrycally for HIGH and HIHI threshold.
It does that for all channels skipping the Gains and the Off Sets because this data are not stored.
For example is ratio are 0.9 and 0.7 and the mean is 10, thresholds will be LOLO=7, LOW=9, HIGH=11, HIHI=13.
You can run the script on pianosa writing on a terminal '/opt/rtcds/caltech/c1/scripts/SUS/set_thresholds.py' and the arguments.
I already run my program with those arguments: 1000123215 600 0.9 0.7
The time is of this morning at 5:00 for 10 minutes
This is the help I wrote
HELP: This program set the thresholds for the "alarm mode" of the C1SUS_SUMMARY.adl medm screen.
Written by Manuel Marchio`, visiting student from University of Pisa - INFN for the 2011 summer at Ligo-Caltech. Thrusday, 15th September 2011.
The 1st argument is the time in gps format when you want to START the mean
The 2nd argument is the DURATION
The 3rd argument is the ratio of the LOW and the HIGH thresholds. It must be in the range [0,1]
The 4th argument is the ratio of the LOLO and the HIHI thresholds. It must be in the range [0,1]
Example: path/set_thresholds.py 1000123215 600 0.9 0.7
and if the the mean is 10, thresholds will be set as LOLO=7, LOW=9, HIGH=11, HIHI=13
I took a dark noise measurement for the ITMY QPD, for comparison with measurements of the oplev noise later on. Initially I was plotting the data from test points after multiplication by the oplev matrix (i.e. the OLPIT_IN1 / OLYAW_IN1), but found that the dark noise level seemed higher than the bright noise level (!?). Kiwamu realised that this is because at that test point the data is already divided by QPD SUM, thus making the dark noise level appear to be greater than the bright level, since QPD SUM is much smaller for the dark measurements. The way around this was to record the direct signals from each quadrant before the division. I took a power spectrum of the dark noise from each quadrant, then added them in quadrature, then divided by QPD SUM at the end to get an uncalibrated PSD. Next I will convert these into the equivalent for pitch and yaw noise spectra. To calibrate the plots in radians per root Hz requires some specific knowledge of the oplev path, so I won't do this until I have adjusted the path.
After Jamie installed the c1oaf model ( entry 5424 ) I went and checked the intermodel communication.
Remember the config is:
c1lsc ->SHMEM-> c1oaf
c1oaf ->SHMEM-> c1lsc
c1pem ->SHMEM-> c1rfm ->PCIE-> c1oaf
I checked at least one of every communications type.
-All signals reach their destinations.
-c1lsc_to_c1oaf_via_shmem is more noisy adding noise to the signal. lsc runs at 16kHz and oaf at 2kHz but that should actually smooth things out.