I turned ON the laser at the X end station, which had been OFF for several weeks because of the crane business.
Now the green beam hits the ITMX and I got a reflection back to the end table.
This green beam will be a nice reference when we install the green periscope in the chamber.
If it's necessary, feel free to correct the alignment of the green beam during my absence.
How to minimize particles entering the vacuum envelope.
Just the way it was in August 2011 vent and before.
The portable HEPAs were set up at ETMY and ITMY with CP STAT 100 curtains.
The 40m particles on the floor at ITMY 3000-5000 counts of 0.5 micron cf / min and 0.3 micron size particles are 55,000 - 65,000 counts cf / min
At this condition the MET One Counter #3 on the floor inside the tent goes to zero count of 0.5 micron and 20-40 counts cf / min for 0.3 micron when the tent is slightly overpressured.
Some more numbers we found while working in/around the chamber today:
These numbers were measured using our particle counter, which has a pump rate of 0.1 cfm, so the numbers above are 10x the numbers shown on the instrument after a measurement to account for this.
Essentially, the chamber is pretty dirty. Peeling the F.C with hard to reach optics like the ITM installed in place is not really feasible, and after peeling the F.C, we are looking at a best case of an additional 1-2 weeks in air to align the IFO, during which the optic is apparently exposed to quite a lot of particulates. In fact, with the high intensity flashlight left on, I actually saw some flecks of dust occassionally floating around inside the chamber while I was working on the optic. But this is just something we have to accept I guess.
Sorry folks! I couldnt get to the elog and didnt know that the elog was crashing every time I tried to access it.
But have found other means to access it and the elog is safe for now!
The IFO room temp is up a bit and it is coming down. The out side temp is not really high.
The temperature is decreasing slowly but is still above 24 C.
The IFO room temp is up
Steve, Rob and Alberto
Starting capacitor 216 miroFarad was installed on the compressor. Water lines were connected to the MOPA as corrected, so the flow meter readings are logical.
Now IN means flowing water in the direction of black arrow on the hose.
We struggled with the Neslab presetting: temp, bauds rate and other unknowns till Rob found the M6000 manual on Peter king's website.
Alberto realized that the chiller temp had to be reset to 20C on water chiller.
I put 1mg of Chloramin T into the water to restrict the growth of algae in the bath.
The NPRO heat sink was around ~20C without flow meter wheel rotation and the PA body ~25C by touch of a finger
I just opened up the needle valve a litle bit so the flow meter wheel would started rotating slowly.
That small glitch at the end of this 3 hrs plot shows this adjustment.
- The tanks are open
[done] - Remove the PZT cable currently underlying between BS and ITMY chambers
[done] - Put this PZT cable between BS and IMC chambers. Connect it on the PZT on the IMC table (SM1)
[done]- Put the two OSEM cables between BS and ITMY chambers. Connect this cable to SRM.
The connector for this cable at the BS side is coming from Bob's place on Wednesday. We left it disconnected for now.
- Energize all of four PZTs and check the functionality.
Five mechcanical traps set inside of boxes. Red-white warning tape on top of each.
Last jump at rack Y2.
I drained the water and removed side covers from the Neslab RTE 140 refrigerated water cooler unit this morning. The hoses to the laser were disconnected.
This abled you to see the little window of refregerant R404A was free of bubles, meaning: no recharge was needed.
The circulator bath was refilled with 7 liters of Arrowhead distilled water and the unit was turned on.
The water temp was kept 20.00+- .05C without any load. Finally the AC-repair man Paul showed up.
He measured the R404A level to be as specified: 23-24 PSI on the suction side and 310 PSI on the discharge side.
The unit was working fine. Paul found an intermittently functioning starting capacitor on the compressor that was removed.
The 240 micro Farad 120VAC cap will arrive tomorrow
You said that the use of FAXST was forbidden for phds and graduate students. I had to swear on the promise of not ever buying an other FAXST
Steve, Yuta and Jamie
Jam nuts were checked and oplev servos were turned off. Sus summery is below with strain gauge values. Are the strain gauge values have any meaning when the PZT contorrels are off??????????????????
The 40m IFO has reached atmospher in 5 hours. It is ready to open chamber condition. The RGA is pumped with the maglev.
P1 pirani gauge is contact dependent as you see it on the linear plot It will be replaced during this vent.
The venting speed was 2-4 Torr / min
Atm2 shows how the BS is sensing the venting air cylinder changes.
The 4th cylinder of instrument grade air bump is overlapping with our janitor working at the BS chamber.
what is next?
Atm 3, Ron Drever could not celebrate with us because of health issues.
It takes 18 months to double the computational power of microprocessors but it took man thousands of years to invent the zipper. I never really understood that till these days.
Here is a sample of my latest results from Optickle simulations of the locking signal for the Power Recycling Cavity.
Thanks also to Rob's revolutionary bidimensional rotating matrix idea (I can see entire books of linear algebra going to be rewritten now because of that) I could find the way to determine the optimal demodulation phases for the demod signals.
There were also an other couple of missing details. But that came easily along.
The parfor function for the parallel computation in Matlab sped up some loops by a factor of 100.
In these particular plots there's still no CARM offset scan. That's what I'm going to post next on the elog, together with the signals for the other degrees of freedom.
Just to show that I'm confident I'm getting reasonable results, I'll post two PRC scans for different CARM. One set of plots is for the current 40m with -19.78 deg of SRM detuning phase, the other is for the Old Upgrade (9 Mhz vs the 11 currently planned) with no detuning phase.
I'm going to put together the results and get some conclusion about the 3f locking scheme for the current 40m and the upgrade.
There are 4 oscilloscopes left on the AP optical table top.... It's only 25 lbs... Do not leave anything on the optical table tops!
Pasadena reported the Sunday night event as a power transient caused by the trip of a power transmission line. This affected the entire city. Once the loss was detected, the system automatically switches to an alternate source. It was about one second for the system to recover.
2W Innolight, both Lightwaves at the ends, PSL HEPA, Ref Cavity and 3 AC units turned on.
The 40m vacuum did not trip. It is vacuum normal.
The Jetstore computer is indicating power failer.
CVI broadband AR coating was measured at the PSL-enclosure table around 9-10am today. The 2W Innolight first PBS S polarization beam was used with an other 1/2 wave plate and PBS.
W2-PW1-1004-C-633-1064-0 This 0.045" thick window has 0.7- 0.8 % reflected beam on each sides at 5 degrees of incidence, P polarization.
The specification is R avg <0.5 % per surface at 0 degree
Rana wants The device would be useless with such a high R, but R 0.1% is OK so I will get V coating.
CVI V-AR coating at 1064 nm, 0 degree, catalog item is R< 0.25% on each sides,
R <0.1 % is custom at much higher prices.
This custom order should go with other orders that has similar need.
From CVI: 5-6-2014
I checked the trace info on the W2-PW1-1004-C-633-1064-0, BBAR coated window that you received. It is side 1, 0.42%R & side 2, 0.53%R @ 1064nm. And with the shift, I’m not too surprised you ended up with 0.7%. A V coat would start with <0.25% (and more typically coming in at ~0.1%) per surface. As far as stock options, I have a 1”dia x 4mmT, fused silica window that is recorded as side 1, R=0.09 and Side 2, R=0.08% @ 1064. Is this too think or will it work for you?
Thank you for the summary.
I think now you are getting into a phase where you should start doing some quantitative and careful checks.
1. Calculate how much light will be reflected from the cavity if the alignment is perfect.
2. Investigate where those kHz oscillations are coming from.
3. Estimate how much the 1.1 kHz corner frequency in LPF will reduce the phase margin around 10 kHz.
4. Calculate the estimated amplitude of the PDH signal.
5. Compute how big the gain of the PDH box should be.
This is a kind of summary of what I have worked on this week.
Things to do after making a new Simulink model.
1. ssh c1sus, go to /opt/rtcds/caltech/c1/core/advLigoRTS/ and run
bash ./makestuff.sh c1SYS
sed -i 's/RO \(.*SWR.*\)/\1/' /opt/rtcds/caltech/c1/target/$*/$*epics/autoBurt.req
If you don't need to re-install DAQs or screens, just run line 2,3,4, and 7 and go to step #6.
2. ssh c1sus, go to /opt/rtcds/caltech/c1/scripts/ and run
For now, you have to put "1" in "BURT Restore" in GDS screens with in 5-10 secs.
3. Now the DAQ channel numbers are changed. So, go to /cvs/cds/rtcds/caltech/c1/chans/daq/ and run
activateDAQ will activate the following DAQ channels for every optics with data rate 2048Hz;
4. Restart fb. See this wiki page.
Basically you what have to do is kill and restart daqd in fb and restart mx_streams in c1sus.
5. DONE! Burt restore if you want.
6. If you don't need to re-install DAQs or screens;
a. Go to /opt/rtcds/caltech/c1/target/c1SYS/c1SYSepics and run
sudo rmmod c1SYSfe
b. Go to /opt/rtcds/caltech/c1/target/c1SYS/bin/ and run
sudo insmod c1SYSfe.ko
bash ./makestuff.sh c1
sed -i 's/RO \(.*SWR.*\)/\1/' /opt/rtcds/caltech/c1/target/$*/$*epics/autoBurt.req
sudo rmmod c1SYSfe
sudo insmod c1SYSfe.ko
Shade 12 black glass-green lines: 1/8" thick, 6" wide x 7 " high mounted on angle bracket below. Aperture 1" diameter. Let me know what do you think.
Summary: Third unsuccessful attempt at getting ETMX suspended. I think we should dial the torque wrench back down to 1.0 N m from 1.5 N m for tightening the primary clamp at the top of the SOS tower. No damage to magnets, standoff successfully retrieved (it is sitting in the steel bowl)
Unfortunately I don't know of a more deterministic way of deciding on a "safe" torque with which to tighten the bolts except by trial and error. It is also possible that the clamping piece is damaged in some way and is responsible for these breakages, but short of getting the edges chamfered, I am not sure what will help in this regard.
Unrelated to this work: earlier today before the first wire failure, while I was optimistic about doing fine pitch balancing and gluing the standoff, I set up an optical lever arm ~3m in length, with the beam from the HeNe on the clean bench at 5.5 in above the table, and parallel to it (verified using Iris close to the HeNe and at the end of the lever arm). I also set up the PZT buzzer - it needs a function generator as well for our application, so I brought one into the cleanroom from the lab, isopropanol wiped it. The procedure says apply 5Vrms triangular wave at 1000Hz, but our SR function generators can't put out such a large signal, the most they could manage was ~2Vrms (we have to be careful about applying an offset as well so as to not send any negative voltages to the PZT voltage unit's "External input". All the pieces we need for the fine pitch balancing should be in the cleanroom now.
Gautam and Steve,
The clamp's left side was jammed onto the left guide pin. It was installed slit facing left. Gautam had to use force to remove it. The clamp should move freely seating on the guide rods till torque aplied. Do not move on with the hanging of optic with a jammed clamp. Fix it.
Never use force as you are hanging - aligning optic. The clamp is in the shop for resurfacing and slit opening.
I added 600 cc of Arrowhead Distilled Water to the chiller.
60 days plot shows that about every ~ 10 days I have to add some.
Please check the water level yourself.
Suresh and I tweaked the OSEM angles in ETMX yesterday. Last night the ETMs were left free swinging, and today I ran Rana's peakFit scripts on ETMX to check the input diagnolization:
It's well inverted, but the matrix elements are not great:
pit yaw pos side butt
UL 0.3466 0.4685 1.6092 0.3107 1.0428
UR 0.2630 -1.5315 1.7894 -0.0706 -1.1859
LR -1.7370 -1.5681 0.3908 -0.0964 0.9392
LL -1.6534 0.4319 0.2106 0.2849 -0.8320
SD 1.0834 -2.6676 -0.9920 1.0000 -0.1101
The magnets are all pretty well centered in the OSEMS, and we worked at rotating the OSEMS such that the bounce mode was minimized.
Rana and Koji are working on ETMY now. Maybe they'll come up with a better procedure.
The new cold cathode gauge CC1 is in place. We were at atmosphere for 28 days ......more later
cc1 = 2.3e-5 Torr at day 6 vacuum normal
c1sus and c1ioo were restarted. PMC locked.
c1sus and c1iscey were reset. The PMC needed to be locked. MC locked instantly.
The FSS ion pump power supply was turned on.
c1sus needed reset.
There are two new Matlab files on the svn in /mDV/extra/C1. 'mycsd.m' is to calculate the cross-spectral density between two channels, 'csd_40T_40T_SS1.m' calls this function with the available seismic channels and derives a self-noise spectrum for the vertical axis using all three seismometers. The method requires that there are no correlations between two instruments only which is a bad idealization for certain frequencies if you have seismometers of totally different types.
'mycsd.m' uses the high-gain, low-resolution Nuttall window (built-in Matlab function 'nuttallwin.m'). High-gain windows are used for broad-band spectra like seismic spectra, but it should be exchanged by another window if you plan to look at small-bandwidth features like peaks.
Since the three-channel analysis does not require knowledge of response functions, it could be used to evaluate the performance of the adaptive filter. For example, if three channels responding to the same signal are available, then the ratio of any two csds corresponds to one of the relative transfer functions. You can then compare this function with the result produced by the adaptive filter.
Could not get past arm power of ~11 or so. I was suspicious of the transmon high-gain/low-gain PD handover, so I ran the matchTransMon scripts, but that did not help. I also removed the line in the cm_step script that increased the CM gain by 18dB at an arm power of 4. The gain of the CM servo will increase naturally as the power in the IFO builds up, so it may not be good to crank it right away. I tried several other CM gains, and watched the DARM loop, but still could not get past an arm power of ~10-11. I'm not sure what's wrong, but it may be that mysterious CM-servo/McWFS conspiracy, so we can try turning down the McWFS gain next time.
I powered down 1Y1 and 1Y2 instrument racks of MC and RF-systems this morning.
Both racks, SP table, clean tools-parts boxes and MC2 area are also covered with plastics.
Bertin Bros. Construction, Inc is working on the floor preparation. Their head man is Robby Bertin, cell 626. 831.2264
remove tiles, clean off tile glue, drill for ribbed steel bars, rough clean- surface for good bounding. paint floor with bounding agent
Tiles and adhesive removed. There were no dust storms created. Solvent paint- removal made the hole IFO -lab smell like the paint shop.
The south door is open with a fan blowing air inside. The north-west door is open through control room to outside to let air rinse the drying
paint-removal. Koji is taking lunch break while test riding our new PSL table legs.
I 've just found this time capsule note from Nov. 26, 2000 by Kip Thorne: LIGO will discover gravitational waves by Dec.31, 2007
Why do we have these timing blanks?