For the Laser Gyro, I wondered how much mechanical noise we might get with a non-suspended cavity. My guess is that the PMC is better than we could do with a large ring and that the MZ is much worse than we could do.
Below 5 Hz, I think the MZ is "wind noise" limited. Above 10 Hz, its just ADC noise in the readout of the PZT voltage.
I ramped the MZ PZT (with the loop disabled on the input switch) to calibrate it. Since the transmission has been blocked, I used the so-called "REFL" port of the MZ to do this.
The dark-to-dark distance for the MZ corresponds to 2 consecutive destructive interferences. Therefore, that's 2 pi in phase or 1 full wavelength of length change in the arm with the moving mirror.
Eyeballing it on the DTT plot (after lowpassing at 0.1 Hz) and using its cursors, I find that the dark-to-dark distance corresponds to 47.4 +/- 5 seconds.
So the calibration of the MZ PZT is 88 +/- 8 Volts/micron.
Inversely, that's a mean of 12 nm / V.
why am I calibrating the MZ? Maybe because Rob may want it later, but mainly because Koji won't let me lock the IFO.
Apparently, we haven't had a fast channel for any of the MZ board. So I have temporarily hooked it up to MC_DRUM at 21:13 and also turned down the HEPA. Now, let's see how stable the MZ and PMC really are overnight.
EDIT: it railed the +/- 2V ADCwe have so I put in a 1:4 attenuator via Pomona box. The calibration of MC_DRUM in terms of MZ_PZT volts is 31.8 cts/V.
So the calibration of MC_DRUM1 in meters is: 0.38 nm / count
The free swinging spectra of ITMs, ETMs, BS, PRM and SRM were measured under the vacuum-condition. The attachment are measured spectra.
It looks there are nothing wrong because no significant difference appear from the past data and the current data (under atmosperic pressure).
So everything is going well.
Need to measure the length of the cable, but too lazy to use a measuring tape?
Then you too can become an expert cable length measurer by just using an RF signal generator and a scope:
The T is kind of acting like a beamsplitter in an asymmetric length Michelson in this case. Just as we can use the RF phase shift between the arms to measure the Schnupp asymmetry, we can also use a T to measure the cable length. The speed of light in the cable is documented in the cable catalog, but in most cases its just 66% of the speed of light in the vacuum.
Seems like very strange cable loss numbers. The Heliax is lossier than the RG-174? I wonder how these compare with the specs in the cable catalog?
I did the measurement on a 4.33 meter long cable with SMA connectors at the ends.
Alberto, Jenne, Kiwamu
We together will lead the IFO restoring and the following is our plan.
- - - - -|- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
#.0 | measuring the free swinging spectra (weekend by kiwamu) DONE
#.1 | turn ON the PZTs for steering mirror and so on. (Dec.14 Mon.) DONE
#. 1 | lock around PSL DONE
#.2 | deal with mechanical shutter (Dec.14 Mon.)DONE
#.3 | lock MCs (Dec.14 Mon.)DONE
#.4 | align the IFO (Dec.15 Tue.)DONE
#.5 | lock full IFO (Dec.15 Tue.)DONE
- - - - -|- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Oplev positions before and after drag wiped arm TMs as of yesterday. Slow-mode pumpdown has started with 3/4 turn opened RV1 valve at 8am today.
Pump down is completed. Valve configuration is VACUUM NORMAL. CC1 pressure is in the ~8 e-5 torr PSL output shutter is opened.
Wait, Wait, Wait. You are moving too fast. Go one by one.
Check the PZTs, the MC, initial pointings, IFO mirrors, some of the partial locks, and maybe some momentary full locks?
Once the recover of the IFO is declared, you can proceed to the measurements.
I'm leaving the lab now for less than 2 hours. I should be back in time for when the pumping is finished so that I can measure the finesse again.
I temporarily disconnected the Heliax cable that brings the 166MHz LO to the LSC rack.
I'm doing a couple of measurement and I'll put it back in as soon as I'm done.
These are the losses I measured on a RG-174 cable for the two frequencies that we're planning to use in the Upgrade:
(The cable was 2.07m long. The input signal was +10dBm and the output voltages at the oscilloscope where: Vpk-pk(11MHz)=1.90V, Vpk-pk(11MHz)=1.82V )
I apologize for the lack of correctness on the units in yesterday's elog entry, but I wasn't very sharp last night.
I repeated the measurement today, this time also making sure that I had a 50ohm input impedance set in the scope. These the results for the losses.
I also measured the losses in the Heliax cable going from the 166 MHz LO to the LSC rack:
Attached are updated plots of the T&R Measurements for a variety of mirrors, and diagrams for the setup used to make the measurements.
T is plotted for the 1064 nm measurement, since these mirrors are highly reflective at 1064, and either R or R&T are plotted for the 532 nm measurement, depending on how larger the R signal is.
As with the previous set of plots, the error bars here are purely statistical, and there are certainly other sources of error not accounted for in these plots. In general, the T measurement was quite stable, and the additional errors
are probably not enormous, perhaps a few percent.
The mirrors are:
The free swinging spectra of ITMs, ETMs, BS, PRM and SRM were measured last night in order to make sure that nothing wrong have happened by the wiping.
I think there are nothing wrong with ITMs, ETMs, BS, PRM and SRM successfully.
For the comparison, Yoichi's figure in his elog entry of Aug.7 2008 is good, but in his figure somehow PRM spectrum doesn't look correct.
Anyway, compared with his past data, there are no significant changes in the spectra. For PRM which has no counterpart to compare with, its shape of spectra looks similar to any other spectra. So I think PRM is also OK. The measured spectra are attached below.
I replaced the SMA end connector for the 166 MHZ Local Oscillator signal that goes to the back of the flange in the 1Y2 rack. The connector had got damaged after it twisted when I was tigheting the N connector of the Heliax cable on the front panel.
The vacuum system is at 760 torr All chambers with doors on and their annuloses are pumped down.
PSL output shutter is still closed. We are fully prepared to star slow pump down tomorrow.
The plan is to reach 1 torr ~ in 6 hrs without a creating a sand storm.
last 20 days - including the pounding from next door
[Everybody: Alberto, Kiwamu, Joe, Koji, Steve, Bob, Jenne]
The last heavy door was put on after lunch. We're now ready to pump.
The frame builder was power cycled during the morning bootfest. I have restarted the backup script once more.
All the front ends are back up.
I found all the front-ends, except for C1SUSVME1 and C0DCU1 down this morning. DAQAWG shows up green on the C0DAQ_DETAIL screen but it is on a "bad" satus.
I'll go for a big boot fest.
I burtrestored all the snapshots to Dec 9 2009 at 18:00.
Note: The set point C1:PSL-FSS_RCPID_SETPOINT is 37.0 on C1PSL_FSS_RCPID.adl.
Now the temp is recovering with its full speed. At some point we have to restore the value of the FSS SLOW DC as the temp change drag it up.
Koji, Jenne, Rob
We found that the RCPID servo "setpoint" was not in the relevant saverestore.req file, and so when c1psl got rebooted earlier this week, this setting was left at zero. Thus, the RC got a bit chilly over the last few days. This channel has been added.
Also, RCPID channels have been added (manually) to conlog_channels.
Instead of doing RCG stuff, I went to Millikan to work on data analysis as I couldn't stand the fumes from the construction. (this morning, 8am)
Diesel fumes are pumped away from control room AC intakes with the help of newly installed reflector boxes on the CES wall fans.........see # 2272
Well, I get the point now. It could be either seismic or change in the suspension Q.
The pendulum memorizes its own state for a period of ~ Q T_pend. (T_pend is the period of the pendulum)
If the pendulum Q is very high (>104), once the pendulum is excited, the effect of the excitation can last many hours.
On the other hand, in our current case, we turned on the damping once, and then turned off the damping.
Again it takes ~Q T_pend to be excited.
In those cases, the peak height is not yet before in equilibrium, and can be higher or lower than expected.
So, my suggestion is:
Track the peak height along the long time scale (~10hrs) and compare between the previous one and the current one.
This may indicate whether it is equilibrium or not, and where the equilibrium is.
If such variation of the peak heights is cased by the seismic activity, it means the seismic level change by several 10 times. It sounds large to me.
Okay, now the data are attached. At that time I just wanted to say like the follower.
- - -
In the free-swinging spectra around ~0.5Hz, you can see the two resonances, which come from pitch and yaw mode of the pendulum.
Note that, the vertical and the horizontal axis are adjusted to be the same for the two plots in the figure .
And I found that
* the floor levels are almost the same (the factor of about 1.5 or something like that) compared to the past.
* however the peak heights for two resonances are several 10 times smaller than the past.
* this tendency are shown in all of the data (ITMX, ETMX, ETMY).
If such variation of the peak heights is cased by the seismic activity, it means the seismic level change by several 10 times. It sounds large to me.
By the way I found a trend, which can be seen in all of the data taken today and yesterday.
The resonances of pitch and yaw around 0.5Hz look like being damped, because their height from the floor become lower than the past.
I don't know what goes on, but it is interesting because you can see the trend in all of the data.
[Kiwamu, Jenne, Alberto, Steve, Bob, Koji]
We finished wiping of four test masses without any trouble. ITMY looked little bit dusty, but not as much as ITMX did.
We confirmed the surface of the ITMX again as we worked at vertex a lot today. It still looked clean.
We closed the light doors. The suspensions are left free tonight in order to check their behavior.
Tomorrow morning from 9AM, we will replace the door to the heavy ones.
Please do not touch the watchdogs for all SUSs except for MCs,
because I am going to measure the free swinging spectra for ITMs, ETMs, BS, PRM, SRM tonight.
Today, it is good chance to summarize those data under atmospheric pressure.
I finally got around to taking a look at the digital camera setup today. Rob had complained the client had stopped working on Rosalba.
After looking at the code start up and not complain, yet not produce any window output, it looks like it was a network problem. I tried rebooting Rosalba, but that didn't fix anything.
Using netstat -an, I looked for the port 5010 on both rosalba and ottavia, since that is the port that was being used by the camera. Ottavia was saying there were 6 established connections after Rosalba had rebooted (rosalba is 18.104.22.168). I can only presume 6 instances of the camera code had somehow shutdown in such a way they had not closed the connection.
[root@ottavia controls]#netstat -an | grep 5010
tcp 0 0 0.0.0.0:5010 0.0.0.0:* LISTEN
tcp 0 0 22.214.171.124:5010 126.96.36.199:57366 ESTABLISHED
tcp 0 0 188.8.131.52:5010 184.108.40.206:58417 ESTABLISHED
tcp 1 0 220.127.116.11:46459 18.104.22.168:5010 CLOSE_WAIT
tcp 0 0 22.214.171.124:5010 126.96.36.199:57211 ESTABLISHED
tcp 0 0 188.8.131.52:5010 184.108.40.206:57300 ESTABLISHED
tcp 0 0 220.127.116.11:5010 18.104.22.168:57299 ESTABLISHED
tcp 0 0 22.214.171.124:5010 126.96.36.199:57315 ESTABLISHED
I switched the code to use port 5022 which worked fine. However, I'm not sure what would have caused the original connection closure failures, as I test several close methods (including the kill command on the server end used by the medm screen), and none seemed to generate this broken connection state. I rebooted Ottavia, and this seemed to fix the connections, and allowed port 5010 to work. I also tried creating 10 connections, which all seem to run fine simultaneously. So its not someone overloading that port with too many connections which caused the problem. Its like the the port stopped working somehow, which froze the connection status, but how or why I don't know at this point.
The construction activity is shaking the tables in the control room. The compactor- large remote controlled jackhammer is in the bottom of the 16-17 ft deep hole 15 ft east of ITMY in CES bay. The suspensions are holding OK. PRM, MC1 and MC3 are effected mostly.
We like to see it if you think this is interesting.
... Just a naive guess: Is it just because the seismic level got quiet in the night?
You looks consistently confused some words like damping, Q, and peak height.
dy = H dx
As the damping makes the Q lower, the peak height also gets lowered by the damping.
But if the disturbance gets smaller, the peak height can become small even without any change of the damping and the Q.
The free swinging spectra of ETMY and ITMX were taken after today's wiping, in order to check the test masses.
These data were taken under the atmospheric pressure condition, as well as the spectra of ETMX taken yesterday.
Compared with the past (see Yoichi's good summary in Aug.7 2008), there are no significant difference.
There are nothing wrong with the ETMY and ITMX successfully.
Jenne, Kiwamu, Koji, Alberto, Steve, Bob
ITMX was wiped without having to move it.
After 'practice' this morning on ETMY, Kiwamu and I successfully wiped ITMX by leaning into the chamber to get at the front face.
Most notable (other than the not moving it) was that inspection with the fiber light before touching showed many very small particles on the coated part of the optic (this is versus ETMY, where we saw very few, but larger particles). The after-wiping fiber light inspection showed many, many fewer particles on the optical surface. I have high hopes for lower optical loss here!
Jenne, Kiwamu, Alberto, Steve, Bob, Koji
We wiped ETMY after recovery of the computer system. We take the lunch and resume at 14:00 for ITMX.
Detailed reports will follow.
Alberto, Kiwamu, Koji,
this morning we found the RFM network and all the front-ends down.
To fix the problem, we first tried a soft strategy, that is, we tried to restart CODAQCTRL and C1DCUEPICS alone, but it didn't work.
We then went for a big bootfest. We first powered off fb40m, C1DCUEPICS, CODAQCTRL, reset the RFM Network switch. Then we rebooted them in the same order in which we turned them off.
Then we power cycled and restarted all the front-ends.
Finally we restored all the burt snapshots to Monday Dec 7th at 20:00.
Opening of ETMY has been put on hold to deal with the computer situation. Currently all front end computers are down. The DAQ AWGs are flashing green, but everything else is red (fb40m is also green). Anyhow, we'll deal with this, and open ETMY as soon as we can.
The computers take priority because we need them to tell us how the optics are doing while we're in the chambers, fitzing around. We need to be sure we're not overly kicking up the suspensions.
In this night, I checked the free swinging spectra of ETMX to make sure nothing wrong with ETMX by the wiping.
Compared with the past (Aug.6 2008), the spectra of ETMX doesn't show significant change.
Successfully the wiping activity didn't change its configuration so much and didn't bring bad situations.
(bad situation means for example, the suspended components hit some others).
The spectra of ETMX by DTT are attached. Also you can see the past spectra in Yoichi's entry.
Yoichi's data was taken during the air-pressure condition, so it's good for comparing.
Actually I compared those data by my eyes, because I could not get the past raw data somehow.
The resonant frequencies and their typical height changed a little bit, but I think those are not significant.
NOTE: In the figure, pitch and yaw modes (~0.57Hz and ~0.58Hz) look like having a smaller Q-factor than the past.
I have made some measurements of the R value for some coatings we are interested in. The plots have statistical error bars from repeated measurements, but I would suspect that these do not dominate the noise, and would guess these should be trusted to plus or minus 5% or so. They still should give some indication of how useful these coatings will be for the green light. I plan to measure for the ITM as soon as possible, but with the venting and finals this may not be until late this week.
EDIT (12/9/09): I fixed the label on the y axis of the plots, and changed them to png format.
[Koji, Jenne, Alberto, Steve, Bob]
ETMX has been drag wiped.
Around 2:45pm, after the main IFO volume had come up to atmospheric pressure, we removed both doors to the ETMX chamber. Regular procedures (wiping of O-rings with a dry, lint-free cloth, covering them with the light O-ring covers, etc.) were followed. Koji took several photos of the optic, and the rest of the ETMX chamber before anything was touched. These will be posted to the 40m Picasa page. Steve and Koji then deionized the optic.
Koji removed the bottom front earthquake stop, and clamped the optic with the remaining earthquake stops.
The clean syringes were prepared: These are all glass and metal (nothing else) medical syringes. The size used was 100microliters. Earlier today, we had prepared our solvents in small little beakers which had been baked over the weekend. Brand new glass bottles of Acetone and Isopropyl Alcohol were opened, and poured into the small beakers. To make sure we have enough, we have 3 ~10ml beakers of each Acetone and Isopropyl.
We started with Acetone. The syringe was filled completely with acetone, then squirted onto a kimwipe. This was repeated ~twice, to ensure the syringe was well rinsed. Then the syringe was filled a little past the 100 microliter mark. Koji held a piece of lens cleaning paper to ETMX and used an allen wrench underneath the optic to help guide the paper, and keep it near the optic (of course, the only thing in actual contact with the optic was the lens paper). In one smooth shot, the plunger of the syringe was pressed all the way down. (This is a bit tricky, especially when the syringe is totally full. You have to squeeze it so the plunger moves fairly quickly down the barrel of the syringe to get a good arc of liquid. The goal is to shoot all of the solvent to the same place on the lens paper, so that it makes a little circle of wetness on the paper which covers the coated part of the optic. The amount of solvent used should be balanced between having too little, so that the paper is dry by the time it has been wiped all the way down, and too much such that there is still a residue of liquid on the optic after the paper has been removed.) The target was to hit the optic just above the center mark (the oplev was on, so I went for just above the red oplev dot). Immediately after applying the liquid onto the paper, Koji slowly and smoothly pulled down on the lens paper until it came off of the bottom of the optic. The acetone was repeated, for a total of 2 acetone wipes. Because acetone evaporates very quickly, more acetone is used than isopropyl. The optimal amount turned out to be ~115 microliters of acetone. It is hard to say exactly how much I had on the second wipe, because the syringe is not marked past 100 microliters. On the first wipe, with about 105 microliters, the lens paper was too dry at the bottom of the optic.
We then switched to Isopropyl. A new syringe was used, and again we rinsed it by filling it completely with isopropyl, and emptying it onto a kimwipe. This was repeated at least twice. We followed the same procedure for applying liquid to the optic and wiping the optic with the lens paper. On the first try with isopropyl, we used 100 microliters, since that was the preferred amount for acetone. Since isopropyl evaporates much slower than acetone, this was determined to be too much liquid. On the second isopropyl wipe, I filled the syringe to 50 microliters, which was just about perfect. The isopropyl wiping was done a total of 2 times.
After wiping, we replaced the front bottom earthquake stop, and released the optic from the other earthquake stops' clamping. The OSEM values were checked against the values from the screenshots taken yesterday afternoon, and were found to be consistent. Koji took more photos, all of which will be placed on the 40m Picasa page.
We visually inspected the optic, and we couldn't see anything on the optical surface of the mirror. Koji said that he saw a few particulates on some horizontal surfaces in the chamber. Since the optic seemed (at least to the level of human vision without a strong, focused light) to be free of particulates on the optical surface to start with, the suspense will have to remain until we button down, pump down, and try to lock the IFO to determine our new finesse, to see if the wiping helped any substantial amount.
We replaced the regular, heavy door on the inner side of the ETMX chamber (the side closer to the CES building), and put only a light door on the outer side of the chamber (the side closer to the regular walkway down the arm). We will look at the spectra of the OSEMS tomorrow, to confirm that none of the magnets are stuck.
We commence at ~9am tomorrow with ETMY.
* The LED lights are awesome. It's easy to use several lights to get lots of brightness (more than we've had in the past), and the chamber doesn't get hot.
* We should get larger syringes for the acetone for the large optics. It's challenging to smoothly operate the plunger of the syringe while it's so far out. We should get 200 microliter syringes, so that for the acetone we only fill them about half way. It was noticeably easier to apply the isopropyl when the syringe only had 50 microliters.
* It may be helpful to have a strong, focused optical light to inspect the surface of the mirror. Rana says that Garilynn might have such an optical fiber light that we could borrow.
Steve, Jenne, Koji
09:30 25 torr
10:30 180 torr
11:00 230 torr
12:00 380 torr
13:00 520 torr
14:30 680 torr - Finish. It is already over pressured.
There's a large broadband increase in the MC_F spectrum. I'm not totally sure it's real--it could be some weird bit-swapping thing. I've tried soft reboots of c1susvme2 and c1iovme, which haven't helped. In any case, it seems like this is preventing any locking success today. Last night it was fine.
Rebooting c1iovme (by keying off the crate, waiting 30 seconds, and then keying it back on and restarting) has resolved this. The frequency noise is back to the 'usual' trace.
NOTE: HEPA is on at its full.
[[[OK]]] Align the suspended optics (by Rob)
[[[OK]]] Align the oplevs again
[[[OK]]] Take snapshots for the suspensions/QPDs/IO QPDs/PZT strain gauges
[[[OK]]] Align the IP_POS, IP_ANG
[[[OK]]] Align the PSL table QPDs, the MC WFS QPDs, and the MCT QPD
[[[OK]]] Align the aux laser for the absolute length
Align the suspended optics (by Rob)
Align the oplevs again
Take snapshots for the suspensions/QPDs/IO QPDs/PZT strain gauges
Align the IP_POS, IP_ANG
Align the PSL table QPDs, the MC WFS QPDs, and the MCT QPD
Align the PSL table QPDs, the MC WFS QPDs, and the MCT QPD
Align the aux laser for the absolute length
o Go to only ITMX mode:
Save the alignment of the mirrors. Activate X-arm mode. Misalign ITMY and ETMX.
o Inject the aux beam:
Open the shutter of the aux NPRO. Turn the injection flipper on.
o Look at the faraday output:
There are several spots but only one was the right one. Confirm the alignment to the thorlabs PD. Connect the oscilloscope to the PD out with a 50Ohm termination.
Thanks to the Alberto's adjustment, the beat was already there at around 10MHz. After the PD adjustment, the DC was about 600mV, the beat amplitude was about 50mVpp.
o Adjust the aux beam alignment:
Adjust the alignment of the aux beam by the steering mirrors before the farady isolator. These only change the alignment of the aux beam independently from the IFO beam.
After the alignment, the beat amplitude of 100mVpp was obtained.
Close the shutter of the NPRO. Turn off the flipper mirror. Restore the full alignment of the IFO.
Taking a cue from entry 2346, I immediately went for the nuclear option and powered off fb40m. Someone will probably need to restart the backup script.
Backup script restarted.