2005 ALL oplev servos use Coherent DIODE LASERS # 31-0425-000, 670 nm, 1 mW
Sep. 28, 2006 optical lever noise budget with DC readout in 40m, LIGO- T060234-00-R, Reinecke & Rana
May 22, 2007 BS, SRM & PRM He Ne 1103P takes over from diode
May 29, 2007 low RIN He Ne JDSU 1103P selected, 5 purchased sn: T8078254, T8078256, T8078257, T8078258 & T8077178 in Sep. 2007
Nov 30, 2007 Uniphase 1103P divergence measured
Nov. 30, 2007 ETMX old Uniphase 1103P from 2002 dies: .............., running time not known......~3-5 years?
May 19, 2008 ETMY old Uniphase 1103P from 1999 dies;.....................running time not known.....~ ?
Oct. 2, 2008 ITMX & ITMY are still diodes, meaning others are converted to 1103P earlier
JDSU 1103P were replaced as follows:
May 11, 2011 ETMX replaced, life time 1,258 days or 3.4 years
May 13, 2014 ETMX , LT 1,098 days or 3 y
May 22, 2012 ETMY, LT 1,464 days or 4 y
Oct. 5, 2011 BS & PRM, LT 4 years, laser in place at 1,037 days or 2.8 y
Sep. 13, 2011 ITMY old 1103P & SRM diode laser replaced by 1125P ..........old He life time is not known, 1125P in place 1,059 days or 2.9 y
June 26, 2013 ITMX 622 days or 1.7 y note: we changed because of beam quality.........................laser in place 420 days or 1.2 y
Sep. 27, 2013 purchased 3 JDSU 1103P lasers, sn: P893516, P893518, P893519 ......2 spares ( also 2 spares of 1125P of 5 mW & larger body )
May 13, 2014 ETMX, .............laser in place 90 d
May 22, 2012 ETMY,
Oct. 7, 2013 ETMY, LT 503 d or 1.4 y............bad beam quality ?
Aug. 8, 2014 ETMY, .............laser in place 425 days or 1.2 y
Sept. 5, 2014 new 1103P, sn P893516 installed at SP table for aLIGO oplev use qualification
March 19, 2015 2 new JDSU 1103P, sn P919645 & P919639 received from Thailand through Edmond Optics. Mfg date 12/2014............as spares
May 23, 2016 ITMX dead laser sn P845648 replaced after 1062 days [2.9 yrs] by 1103P, sn P859884, with output output 2.6 mW, nicely round beam quality at 15 meters.
July 27, 2016 2 new 1103P from Edmonds in: P947034 & P947039, manf. date April 2016,
Oct. 5, 2015 ETMY He/Ne replaced by 1103P, sr P919645, made Dec 2014, after 2 years
Jan. 24, 2017 ETMY He/Ne replaced by 1103P, sr P947049, made Apr 2016, after 477 hrs running hot
March 17, 2017 ETMX laser replaced at LT 3y with 1103P, sn T8070866
Jan. 26, 2017 RIN test stared with P947034, made Apr. 2016
Apr. 10, 2017 purchased two 1103P from Edmund: sr P964438 & sr P964431, made 02/2017
1103P, sn P893518 of 2013 vintage is dead at the sus fiber demo
July 19, 2017 1103P, sn P964438 as new installed at the south end for the glass fiber illumination. Turn laser off when you are done.
The $1000 HeNe should not be used for illuminating fibers.
You should purchase these (total price per laser less than $6):
All oplev qpd quadrons were zeroed by offset in blocked dark condition.
I heard that Steve did great work on oplev in Feb 2012.
Here's summary what happened to oplev since then.
Someone changed oplev filters and gain. I couldn't find elog about it. Does anyone know?
Quadrant sum (C1:SUS-XXX_OLSUM) for each optic now and in Feb 2012 is
ITMX ITMY ETMX ETMY BS PRM SRM
2456 14630 1476 14885 3650 4302 2937 counts (now)
1300 14500 900 9000 3500 4000 2600 counts (Feb 6, 2012 elog #6256)
0.025 0.3 0.2 0.2 0.05 0.06 0.04 mW on QPD (Feb 6, 2012 elog #6256)
1350 15000 1500 15500 3500 4000 2600 counts (Feb 23, 2012 elog #6744)
ETMX oplev laser was replaced on May 22, 2012, and quadrant sum was 20500 counts at that time (elog #6656).
Oplev servo openloop transfer functions:
In Feb 2012, gains were adjusted and filter settings are recorded by Steve.
For all pitch OLTF, see elog #6309.
For all yaw OLTF, see elog #6323.
All the filters in Feb is listed in elog #6744.
Filters now are messed up, as Jamie pointed out in elog #6743.
Below is the current filter settings.
I turned ELP and RLP filters on, which wasn't on to cut-off noises at higher frequencies.
I left resonant gains of ETMs because I don't know what they are for.
I put ELP35 for ITMs, BS, PRM and SRM. I put RLP80 for BS, PRM and SRM.
I will leave ELP35 off for BS and SRM because they oscillate currently. ELP50 and ELP40 is on for a substitution. I will readjust them soon.
I don't know who changed all gains (except for PRM, which I adjusted in elog #6952). It doen't look like it is because of change in quadrant sum.
I also don't know who deleted 3.3 Hz resonant gain for BS.
I put all similar filters in same place to make it organized. Now, basic fitlers are organized. We may need some resonant gains for each optics.
All oplevs servos turned off to protect our suspentions from vibration due to drilling and pounding in CES high bay area.
This activity will be done from 10 am till 3 pm today.
Meanwhile our IFO-air conditions are turned off for maintenance.
Their performance of 6 months is shown on plot.
Last night I found that the sign of the oplev control of PITCH on ETMY was wrong. I flipped it to the correct sign.
We've been locking the Y arm by feeding a signal back to ITMY because pushing ETMY somehow made the lock unstable in the angular motion.
After the correction of the oplev contol sign, I was able to keep the lock robustly by pushing ETMY.
Somehow the angular stability of the central part have not been so great.
Also the angular motions look fluctuating a lot and they seem to be related with the glitches.
I took the oplev spectra when the PRMI is locked and unlocked to see whether if something obviously crazy is going on or not.
They seem ok to me except that the PRM pitch shows an extra bump at around 2-3 Hz when the PRMI is locked. But I don't think it's prominent.
- The attached files show the oplev spectra. When the PRMI is locked the PRM and both ITMs are under the length control.
(red) pitch when PRMI is locked
(blue) yaw when PRMI is locked
(orange) pitch without any length controls
(cyan) pitch without any length controls
Kiwamu showed me how to do transferfunction of oplev pitch
Kiwamu, Koji and Steve,
Arm aligned separatly and oplev qpds were centered including BS. Than we realigned manually DRM and centered their qpds.
ALL SUS oplevs were centered to resonating cavities.
We've provided acoustic excitation using speakers on the AS table and saw that PSD of YARM feedback signal increased in the frequency range 50 - 100 Hz. Meanwhile, XARM feedback signal did not change. Moreover, YARM noise is much higher at these frequencies compared to XARM.
The problem was with YARM oplev servos. Both ITMY and ETMY produced noise to YARM length. ITMY oplev signal had a huge resonance at 55 Hz. We measured coherence with accelerometers, it was 0.8. It turned out that one of the mirror mounts was not fixed in the oplev path. When we fixed it, noise has gone.
Note: speakers were on AS table but mirror mounts could steel feel it on ITMY table.
Then we had a look on ETMY table. We saw a mirror on suspiciously long mirror mount that was used in the ETMY oplev path. We slightly kicked long mount with a small screwdriver and YARM control signal went up with resonance at 100 Hz.
I will just leave the picture of spectrum that shows the injected acoustic sound effects due to the oplevs.
red line: POY error without oplev feedback nor acoustic noise
blue line: POY error without oplev feedback but with acoustic noise
brown line: POY error with oplev feedback but without acoustic noise
green line: POY error with oplev and acoustic noise
You can see there is noise only at green line around 70 - 100 Hz. And it does not look like the acoustic signal is injected directly to the arms but the acoustic sound couples to the original noise source.
Tonight I centered the oplevs for ITMX/Y, SRM, PRM, BS.
After doing that I noticed that the BS drifted a little from where I had set it.
Oplevs centered in flashing condition, except PRM and SRM. IP POS centered also,
I like this new summing screen of Jenne.
The IFO_overview of oplevs seems ok, The servos are working fine. The green arms are locked, but master and oplev_summary monitoring screens are not.
I'm proposing to Erick G. to postpone the oplev noise measurement.
Kiwamu and Steve, from yesterday
PRM and BS oplev paths were relaid after setting 1/2 OSEM voltages. The incident beam on suspended optics are centered within ~ +- 2 mm
I noticed many unvected ss screws are used on the big Al table tops. The SS 1/4-20 screws
used on the optical tables in vacuum MUST be VENTED!
Also, please use SS clamps. Replace aluminum ones when you can. We have plenty baked ones.
I have recentered the oplev beams, including BS, ITMs and ETMs.
Yesterday Steve and I revived two legs to mount some optical breadboards outside of the end table.
These legs had been used as oplev's mounts many years ago, but now they are served for 40m upgrading. These are really nice.
By putting them on the side of the end table, a mirror mounted on the top of the leg can reflect the beam outside of the end table.
Once we pick off the green beam from the end table to its outside, the green beam can propagate through the 40m walkway along the Y-arm.
So that we can measure the beam profile as it propagates.
These legs are also going to be used during mode matching of the vacuum optics.
I have made my own AutoCAD WS account and put the latest 40m layout.
AutoCAD WS is a free cloud service which enable us to browse/edit the DWG files.
You can view/play/print it from the following link even without making the account.
If you make your account you can actually save it although the editing capability is somewhat limited.
- It needs the Flash plug-in and Internet connection.
- I think Safari is the most stable platform on Mac. (i.e. I had some malfunctions with Firefox and Chrome)
this afternoon we centered the optical levers for all the optics.
To do that we first ran the alignment scripts for all the cavities.
I centered optical levers of ITMX,BS,ETMY. I also change the position of optical levers of ITMX, ETMY, ITMY, BS on Friday night(9/21), of ITMX, ETMY, BS on Monday night. Both are around 6:00 ~ 7:00.But centering on Monday was totally wrong, because I centered with not good IFO alignment.
The attachment is the 5 days trend of the opt lev of ITMX. First gap is alignment on Friday and Second gap is the alignment on Monday. Now I centered after locking the FPMI.
The attachment 2 is the last 6 hours data. The gap on 9/25 00:00 and 1:30(UTC) is because the alignment of the cavity and the last gap is because of centering of the optical lever.
Sanwiched wall as shown: 1" clear acrylic, 2 layers of 0.004" thick "window tint", 1 layer of 0.007" thermashield and 0.125" yellow acrylic
Visibility: 70 %, Transmission of 1064 nm 2-3 % at 0-50 degrees incident power density 0.7 W/mm2
Max power 100 mW
Max power 100 mW
Good. The power density and max power are not important (especially since you don't define a quantitative way to spec them). We ONLY care about the transmission.
I found ITMX-ISCT and BS-ISCT ( IFO sensing-control table) not covered this morning. Please do not leave tables open.
Sanwiched wall as shown: 1" clear acrylic, 2 layers of 0.004" thick "window tint", 1 layer of 0.007" thermashield and 0.125" yellow acrylic
Visibility: 70 %, Transmission of 1064 nm 2-3 % at 0-50 degrees incident, power density ~ 0.7 W/mm2
More details about this east end " acrylic + " enclosure ( optical table cover ) can be found elog entry 6210, 7194 and 7106
Window tinted layer transmission plot is below.
We have a film which may meet your requirements and the values are shown below:
Wavelength (nm) Transmission Reflectance(front) Reflectance (back)
1060 .0772 .604 .759
1070 .0723 .615 .772
These values are taken from the LBNL Optics 6 program and if you have access to that program, the NFRC ID for the film is 202. If you do not have access to the program, I have a captured the graph which may be of some help. I apologize for the appearance of the graph but someone at LBNL decided it would look better with a dark gray background – the yellow is the transmission curve, the blue is the reflectance (front) and the green is the reflectance (back).
The film is referred to as “Hilite 70” and has a 72% visible light transmission. These results were obtained with the film mounted on 1/8” clear glass.
Saint-Gobain Performance Plastics
Please consider your environmental responsibility before printing this email.
PSL, AP, ETMY and ETMX optical tables were scanned for stay beam.
3/4 " thick colored acrylic material will be used in this air tight design. Surgical tubing for o-ring. We may have to put an o-ring into the bottom to have it really air tight.
The top drawing is not ready. It will have handle and industrial grade L-handle lock pin to hold cover down. There will be 2 one inch od post in the midle of the table to hold the cover and lock the ball pin.
I'm waiting for your inputs, so I can send this preliminary design out for quote.
The present plan to go with clear cast acrylic plexiglass 1" thick side wall and two clear 1/2 thick top cover.
The inside would be lined with light braun YAG safety window sheets 0.14" VLT ~25% OD 4 @ 532nm & OD 5 @ 1064nm
ALL optics (including MC) were kicked and left free swinging at:
The "opticshutdown" script was also run, which should turn the watchdogs back on in 5 hours (at 6am).
ottavia has been reinstalled with Ubuntu 10.04 LTS, and has been configured as a CDS workstation.
I have been maintaining a script that takes a stock 10.04 install and configures it as a workstation. I've attached it here, but it lives at:
The script is designed to be idempotent, i.e. it can be run on a machine that has already been configured and it will either have no affect or update.
# This is a CDS workstation setup script for Ubuntu 10.04 It is
# idempotent, so running it on an already configured workstation is
if [[ $(id -u controls) != 1001 ]] ; then
As preparation for the upcoming planned power outage we turned turbos, RGA off and closed valves.
IFO chamber is not pumped now. Small leaks and out gassing will push the pressure up slowly. At 3 mTorr of P1 the PSL output shutter
will be closed by the interlock.
It is OK to use light in the IFO up to this point.
Our vacuum was not pumped for 4 days. The computers were not up when we started pumping again. The manual reading on P1 was 15 mTorr.
This means that our outgassing plus leakrate is ~3.8 mTorr /day
3-5 mTorr / day is normal
Two out of the four over-head fluorescent lights in the X end of the interferometer were flickering today.
Folks were complaining that they were getting zeros whenever they tried to open fast channels in DTT or Dataviewer. It turned out that the problem was that all available test points were in use in the c1lsc model:
There is a limit to how many test points can be open to a single model (in point of fact I think the limit is on the data rate from the model to the frame builder, not the actual number of open test points). In any event, they was all used up. The grid at the bottom right of the C1LSC GDS screen was all full of non-zeros, and the FE TRATE number was red, indicating that the data rate from this model had surpassed threshold.
The result of this overbooking is that any new test points just get zeros. This is a pretty dumb failure mode (ideally one would not be able to request the TP at all with an appropriate error message), but it is what it is. This usually means that there are too many dtt/dataviewers left with open connections.
We tried killing all the open processes that we could find that might be holding open test points, but that didn't seem to clear them up. Stuck open test points is another known problem. Referencing the solution in #6968 I opened the diag shell and killed all test points everywhere:
controls@pianosa:~ 0$ diag -l -z
Set new test FFT
NDS version = 12
supported capabilities: testing testpoints awg
diag> tp clear * *
test point cleared
Overnight, the pressure increased from 247 uTorr to 264 uTorr over a period of 30000 seconds. Assuming an IFO volume of 33,000 liters, this corresponds to an average leak rate of ~20 uTorr L / s. It'd be interesting to see how this compares with the spec'd leak rates of the Viton O-ring seals and valves/ outgassing rates. The two channels in the screenshot are monitoring the same pressure from the same sensor, top pane is a digital readout while the bottom is a calibrated analog readout that is subsequently digitized into the CDS system.
We allowed the pumpdown to continue until reaching 9e-4 torr in the main volume. At this point we valved off the main volume, valved off TP2 and TP3, and then shut down all turbo pumps/dry pumps. We will continue pumping tomorrow under the supervision of an operator. If the system continues to perform problem-free, we will likely leave the turbos pumping on the main volume and annuli after tomorrow.
The pressure of the main volume increased from ~1mtorr to 50mtorr for the past 24 hours (86ksec). This rate is about x1000 of the reported number on Jan 10. Do we suspect vacuum leak?
Overnight, the pressure increased from 247 uTorr to 264 uTorr over a period of 30000 seconds. Assuming an IFO volume of 33,000 liters, this corresponds to an average leak rate of ~20 uTorr L / s.
I looked into this a bit today. Did a walkthrough of the lab, didn't hear any obvious hissing (makes sense, that presumably would signal a much larger leak rate).
Attachment #1: Data from the 30 ksec we had the main vol valved off on Jan 10, but from the gauges we have running right now (the CC gauges have not had their HV enabled yet so we don't have that readback).
Attachment #2: Data from ~150 ksec from Friday night till now.
Interpretation: The number quoted from Jan 10 is from the cold-cathode gauge (~20 utorr increase). In the same period, the Pirani gauge reports a increase of ~5 mtorr (=250x the number reported by the cold-cathode gauge). So which gauge do we trust in this regime more? Additionally, the rate at which the annuli pressures are increasing seem consistent between Jan 10 and now, at ~100 mtorr every 30 ksec.
I don't think this is conclusive, but at least the leak rates between Jan 10 and now don't seem that different for the annuli pressures. Moreover, for the Jan 10 pumpdown, we had the IFO at low pressure for several days over the chirstmas break, which presumably gave time for some outgassing which was cleaned up by the TPs on Jan 10, whereas for this current pumpdown, we don't have that luxury.
Do we want to do a systematic leak check before resuming the pumpdown on Monday? The main differences in vacuum I can think of are
This entry by Steve says that the "expected" outgassing rate is 3-5 mtorr per day, which doesn't match either the current observation or that from Jan 10.
We can pump down (or vent) annuli. If this is the leak between the main volume and the annuli, we will be able to see the effect on the leak rate. If this is the leak of an outer o-ring, again pumping down (or venting) of the annuli should temporarily decrease (or increase) the leak rate..., I guess. If the leak rate is not dependent on the pressure of the annuli, we can conclude that it is internal outgassing.
Somebody changed the settings on painosa without elogging anything about it. Why does this keep happening? I thought the point of the elog was to communicate. I think there are sufficient number of problems in the lab without me having to manually reset the control room workstation settings every week. Please make an elog if you change something.
I finished designing the PCBs for the VME crate back sides (see attached). The project files live on the DCC now at https://dcc.ligo.org/LIGO-D1700058. I ordered a prototype quantity (9) of the PCB printed and bought the corresponding connectors, all will arrive within the next two weeks. See also attached the front panels for the Acromag DAQ chassis and Lydia's RF amplifier unit (the lone +24V slot confuses me: I don't see a ground connector?). On the Acromag panel, six (3x2) of the DB37 connectors are reserved for VME hardware, two are reserve, and I filled the remaining space with general purpose BNC connectors for whatever comes up.
The amplifier unit should use the three pin dsub connectors (3w3?) that we use on many of the other units for DC power, and preferably go through the back panel. You can leave out the negative pin, since you just need +24 and ground.
This is already how it's hooked up. The hole on the from that says +24 V is for an indicator light.