Five mechcanical traps set inside of boxes. Red-white warning tape on top of each.
Last jump at rack Y2.
We could use similar load cells to make the actual weight measurement on the Stacis legs. This seems practical in our case.
I have had bad experience with pneumatic Barry isolators.
Our approximate max compression loads are 1500 lbs on 2 feet and 2500 lbs on the 3rd one.
We've been thinking about putting in a blade spring / wire based aluminum breadboard on top of the ETM & ITM stacks to get an extra factor of 10 in seismic attenuation.
Today Koji and I wondered about whether we could instead put something on the outside of the chambers. We have frozen the STACIS system because it produces a lot of excess noise below 1 Hz while isolating in the 5-50 Hz band.
But there is a small gap between the STACIS and the blue crossbeams that attache to the beams that go into the vacuum to support the stack. One possibility is to put in a small compliant piece in there to gives us some isolation in the 10-30 Hz band where we are using up a lot of the control range. The SLM series mounts from Barry Controls seems to do the trick. Depending on the load, we can get a 3-4 Hz resonant frequency.
Steve, can you please figure out how to measure what the vertical load is on each of the STACIS?
Good going Johannes!
This evening I transitioned the slow controls to c1auxex2.
Gautam and I then proceeded to test basic functionality
Arms are locked, have been for ~1hour with no hickups. We will leave it like this overnight to observe, and debug further tomorrow.
I have just received the scheduling of the PSL self work for tomorrow. Gautam and I agreed that if it is needed I will shut the laser off and cover the hole table with plastic.
Measurements for good fit were made. The new shelf will be installed on next Tuesday at 2pm
The reference cavity ion pump is in the way so the cavity will be moved 5" westward. The shelf height space will be 10" Under shelf working height 18" to optical table.
[ Johannes, Rana, Mark and Steve ]
On the second trial the shelf was installed. Plastic cover removed. South end door put back on and 2W Inno turned on.
Shelf 10 " below the existing one: 92" x 30" x 3/4" melamine (or MDF) covered with white Formica. 200 lbs it's max load. Working distance to top of the table 18"
While moving the RefCav to facilitate the PSL shelf install, I bumped the power cable to the AOM driver. I will re-solder it in the evening after the shelf installation. PMC and IMC have been re-locked. Judging by the PMC refl camera image, I may also have bumped the camera as the REFL spot is now a little shifted. The fact that the IMC re-locked readily suggests that the input pointing can't have changed significantly because of the RefCav move.
1500 and 2000 lbs load cells arrived from MIT to measure the vertical loads on each leg.
M4 local earthquake at 10:10 UTC There is no sign of damage.
....here is an other one.........M5.8 Ferndale, CA at 16:40 UTC
pd80b rga scan at 175 day. IFO pressure 7.3e-6 Torr-it
Condition: vacuum normal, annuloses not pumped. Rga turned on yesterday.
The rga was not on since last poweroutage Jan 2, 2018 It is warming up and outgassing Atm2
Annual crane inspection with load tests is scheduled for Monday, Feb 5, 2018 from 8 to 11:30am
Konecranes rescheduled this appointment to: Monday, Feb 12, 2018
Hornet cold cathode gauge analoge output [ DSub9 pin 3 and 7 ] are wired to go ETMX Acromag. It was reading 4.9V at 7.8e-6 Torr [ 3,110 V 8.35e-5A ] at the end of a 24ft BNC cable. Now it has to be hook up to an Acromag channel.
This will replace the not functioning C1: Vac-CC1_pressure
gautam: the motivation behind hooking this gauge up to our DAQ system is that non-vacuum-system-experts have a quick diagnostic to make sure everything is in order. This gauge is physically placed adjacent to V1, and so if something goes wrong with our vacuum pumps, we would see the effect here immediately. we did note that occassionally, the reading fluctuated by ~1V on the DMM used to check the voltage output at the end of the BNC cable, so we still need to run some long-term stability analysis once this channel is hooked up to the Acromag. For future reference, in order to make this gauge work, we need to check that
There was a power outage.
The IFO pressure is 12.8 mTorr-it and it is not pumped. V1 is still closed. TP1 is not running. The Rga is not powered.
The PSL output shutter is still closed. 2W Innolight turned on and manual beam block placed in its beampath.
3 AC units turned on at room temp 84F
IFO pumped down from 44 mTorr to 9.6e-6 Torr with Maglev backed with only TP3
Aux drypump was helping our std drypump during this 1 hour period. TP3 reached 32 C and slowed down 47K rpm
The peak foreline pressure at P2 was ~3 Torr
Hornet cold cathode gauge setting: research mode, air,
2830 HV 1e-4A at 9.6e-6 Torr,
[ 3110 HV 8e-5A at 7.4e-6 Torr one day later ]
Annuloses are at 2 Torr, not pumped
Valve configuration: vacuum normal, RGA is still off
PSL shutter is opened automatically. Manual block removed.
End IR lasers and doublers are turned on.
NOTE: Maglev " rotation X " on vacuum medm screen is not working! " C1:Vac-TP1_rot " channel was removed. Use " NORMAL X " for rotation monitoring.
*We removed this (i.e. rotation) field from the MEDM screen to avoid confusion.
The ETMX Sorrenson power supply -15V was running at -13.9V
Our 3 cranes passed professional inspection. Fred Goodbar of Konacrane with 450 lbs load at full extension.
Certificates will be posted in 40m wiki as they arrive.
Gautam and Steve,
The "called 225 lbs" steel crane load measured right on 102 kg
The trick to the measurment to maintain 1 mm gap to the central cilynder of the load cell.
The lead plate stabilized the large load.
gautam: some additional notes:
The forline pressure of TP3 was 399 mTorr
It was replaced this morning at TP3 controller 134,638hrs with the "failed TP2 station" drypump. The foreline pressure now at TP3 is 100 mTorr at 6 hrs of operation.[ at day 3 63 mT ]
IFO pressure at CC Hornet 7.9e - 6 Torr
Valve configuration: vacuum normal as TP3 is the forepump of the Maglev & the annuloses are not pumped
PSL shutter closed at 6e-6 Torr-it
The foreline pressure of the drypump is 850 mTorr at 8,446 hrs of seal life
V1 will be closed for ~20 minutes for drypump replacement..........
9:30am dry pump replaced, PSL shutter opened at 7.7E-6 Torr-it
Valve configuration: vacuum normal as TP3 is the forepump of the Maglev & annuloses are not pumped.
TP3 drypump replaced at 655 mTorr, no load, tp3 0.3A
This seal lasted only for 33 days at 123,840 hrs
The replacement is performing well: TP3 foreline pressure is 55 mTorr, no load, tp3 0.15A at 15 min [ 13.1 mTorr at d5 ]
Valve configuration: Vacuum Normal, ITcc 8.5E-6 Torr
Dry pump of TP3 replaced after 9.5 months of operation.[ 45 mTorr d3 ]
The annulosses are pumped.
Valve configuration: vac normal, IFO pressure 4.5E-5 Torr [1.6E-5 Torr d3 ] on new ITcc gauge, RGA is not installed yet.
Note how fast the pressure is dropping when the vent is short.
IFO pressure 1.7E-4 Torr on new not logged cold cathode gauge. P1 <7E-4 Torr
Valve configuration: vac.normal with anunulossess closed off.
TP3 was turned off with a failing drypump. It will be replaced tomorrow.
All time stamps are blank on the MEDM screens.
All rack power supplies labeled if their load changed.
We have the IFO pressure logged again! Thanks Johannes and Gautam
This InstruTech cold cathode ionization vacuum gauge " Hornet " was installed 2016 Sep 14
Here is the CC1 gauge history of 10 years from 2015 Dec 1
The next thing to do is put this channel C1:Vac-CC1_HORNET_PRESSURE on the 40m Vacuum System Monitor [ COVAC_MONITOR.adl ]
gautam 1pm: Vac MEDM screen monitor has been edited to change the readback channel for the CC1 pressure field - see Attachment #2. Seems to work okay.
Pumpdown 80 at 511 days and pd80b at 218 days
Valve configuration: special vacuum normal, annuloses are not pumped at 3 Torr, IFO pressure 7.4e-6 Torr at vac envelope temp 22 +- 1C degrees
CC1 old MKS cold cathode gauge randomly turns on- off. This makes software interlock close VM1 to protect RGA So the closed off RGA region pressure goes up and the result is distorted RGA scan.
CC1 MKS gauge is disconnected and VM1 opened. This reminds me that we should connect our interlocks to CC1 Hornet Pressure gauge.
Valve configuration: special vacuum normal, annuloses are not pumped at 3 Torr, IFO pressure 7.4e-6 Torr at vac envelope temp 22 +- 1C degrres
MCRefl is absent, it is under investigation. I removed a bunch of hardware and note all spare optics along the edges.
Till RIN measurement noise eater is off on 2W laser. The inno 1W has no noise eater.
2010 power v current table is below.
Koji and Kevin measured the output power vs injection current for the Innolight 2W laser.
The threshold current is 0.75 A.
The following data was taken with the laser crystal temperature at 25.04ºC (dial setting: 0.12).
Earth quake M5.3 2018-04-05 19:29:16UTC Santa Cruz Island, CA
Satellite amplifiers labeled with date. Old labels left on.
I've been looking into recovering the seismic BLRMs for the BS Trillium seismometer. It looks like the problem is probably in the anti-aliasing board. There's some heavy stuff sitting on top of it in the rack, so I'll take a look at it later when someone can give me a hand getting it out.
In detail, after verifying that there are signals coming directly out of the seismometer, I tried to inject a signal into the AA board and see it appear in one of the seismometer channels.
ETMX table layout uploaded with beam paths to the wiki.
The pdf file is uploaded into the wiki.
We have calibrated the load cells. The support beams height monitoring is almost ready.
The danger of this measurment that the beams height changes can put shear and torsional forces on this formed (thin walled) bellow
They are designed for mainly axial motion.
The plan is to limit height change to 0.020" max
0, center oplev at X arm locked
1, check that jack screws are carrying full loads and set height indicator dials to zero ( meaning: Stacis is bypassed )
2, raise beam height with aux leveling wedge by 0.010" on all 3 support point and than raise it an other 0.005"
3, replace levelling wedge with load cell that is centered and shimmed. Dennis Coyne pointed out that the Stacis foot has to be loaded at the center of the foot and formed bellow can shear at their limits.
4, lower the support beam by 0.005" ......now full load on the cells
Note: jack screw heights will not be adjusted or touched.......so the present condition will be recovered
[ Dennis Coyne' precision answer ]
Differential Height between Isolators
According to a note on the bellows drawing (D990577-x0/A), the design life of the bellows at ± 20 minutes rotational stroke is 10,000 cycles. A 20 minute angular (torsional) rotation of the bellows corresponds to 0.186" differential height change across the 32" span between the chamber support beams (see isolator bracket, D000187-x0/B).
Another consideration regarding the bellows is the lateral shear stress introduced by the vertical translation. The notes on the bellows drawing do not give lateral shear limits. According to MDC's web page for formed bellows in this size range the lateral deflection limit is approximately 10% of the "live length" (aka "active length", or length of the convoluted section). According to the bellows drawing the active length is 3.5", so the maximum allowable lateral deflection should be ~0.35".
Of course when imposing a differential height change both torsional and lateral shear is introduced at the same time. Considering both limits together, the maximum differential height change should be < 0.12".
One final consideration is the initial stress to which the bellows are currently subjected due to a non-centered support beam from tolerances in the assembly and initial installation. Although we do not know this de-centering, we can guess that it may be of the order of ~ 0.04". So the final allowable differential height adjustment from the perspective of bellows stress is < 0.08". Steve: accumulated initial stress is unknown. We used to adjust the original jack screws for IFO aligment in the early days of ~1999. This kind of adjustment was stopped when we realized how dangereous it can be. The fact is that there must be unknown amount of accumulated initial stress. This is my main worry but I'm confident that 0.020" change is safe.
So, with regard to bellows stress alone, your procedure to limit the differential height change to <0.020" is safe and prudent.
However, a more stringent consideration is the coplanarity requirement (TMC Stacis 2000 User's Manual, Doc. No. SERV 04-98-1, May 6, 1991, Rev. 1), section 2, "Installation",which stipulates < 0.010"/ft, or < 0.027" differential height across the 32" span between the chamber support beams. Again, your procedure to limit the differential height change to < 0.02" is safe.
Centered Load on the STACIS Isolators
According to the TMC Stacis 2000 User's Manual (Document No. SERV 04-98-1, May 6, 1991, Rev. 1), section 2, "Installation", typical installations (Figure 2-3) are with one payload interface plate which spans the entire set of 3 or 4 STACIS actuators. Our payload interface is unique.
Section 2.3.1, "Installation Steps": "5. Verify that the top of each isolator is fully under the payload/interface plate; this is essential to ensure proper support and leveling. The payload or interface plate should cover the entire top surface of the Isolator or the entire contact area of the optional jack."
section 2.3.2, "Payload/STACIS Interface": "... or if the supporting points do not completely cover the top surface of each Isolator, an interface plate will be needed."
The sketch in Figure 2-2 indicates an optional leveling jack which appears to have a larger contact surface area than the jacks currently installed in the 40m Lab. Of course this is just a non-dimensioned sketch. Are the jacks used by the 40m Lab provided by TMC, or did we (LIGO) choose them? I beleive Larry Jones purchased them.
A load centering requirement is not explicitly stated, but I think the stipulation to cover the entire top surface of each actuator is not so much to reduce the contact stress but to entire a centered load so that the PZT stack does not have a reaction moment.
From one of the photos in the 40m elog entry (specifically jack_screw.jpg), it appears that at least some isolators have the load off center. You should use this measurement of the load as an opportunity to re-center the loads on the Isolators.
In section 2.3.3, "Earthquake Restraints" restraints are suggested to prevent damage from earth tremors. Does the 40m Lab have EQ restraints? Yes, it has
Screw Jack Location
I could not tell where all of the screw jacks will be placed from the sketch included in the 40m elog entry which outlines the proposed procedure.
Load Cell Locations
The sketch indicates that the load cells will be placed on the center of the tops of the Isolators. This is good. However while discussing the procedure with Gautam he said that he was under the impression that the load cell woudl be placed next to the leveling jack, off-center. This condition may damage the PZT stack. I suggest that the leveling jack be removed and replaced (temporarily) with the load cell, plus any spacer required to make up the height difference. Yes
If you have any further question, just let me know.
Chief Engineer, LIGO Laboratory
California Institute of Technology
MC 100-36, 1200 E. California Blvd.
20180508 4:49am Cabazon earth quake 4.5M at 79 miles away. ETMX is in load cell measurment condition.
There was an earthquake, all watchdogs were tripped, ITMX was stuck, and c1psl was dead so MCautolocker was stuck.
Watchdogs were reset (except ETMX which remains shutdown until we finish with the stack weight measurement), ITMX was unstuck using the usual jiggling technique, and the c1psl crate was keyed.
Pooja and Keirthana received 40m specific basic safety training.
The final set-up of stack measurment with 3 load cells and 4 leveling wedge mounts as Atm 1
Sensor voltages BEFORE and AFTER this attempt.
Chris replaced some air condition filters and ordered some replacement filter today.
Yesterday morning was dusty. I wonder why?
The PRM sus damping was restored this morning.
Yesterday afternoon at 4 the dust count peaked 70,000 counts
Manasa's alergy was bad at the X-end yesterday. What is going on?
There was no wind and CES neighbors did not do anything.
Air cond filters checked by Chris. The 400 days plot show 3 bad peaks at 1-20, 2-5 & 2-19
Koji's collection of Yend components put away. I cleaned up the Xend bench today.
Loadcells, leveling wedge mounts and related items placed under flowbench cabinet next to Guralp staff.
We have 6 of these boards now in cabinet E7
I wired all 32 channels going to the AA board directly to the ADC as described in the previous log. However, instead of using the old AA board and bypassing the whole circuit, I just used a breakout board as is shown in the first attachment. I put the board back in the rack and reconnected all of the cables.
The seismic BLRMs appear to be working again. A PSD of the BS seismometers is shown in attachment 2. Tomorrow I'll look at how much the ADC alone is suppressing the common mode 60 Hz noise on each of the channels.
Steve: 5 of ADC DAC In Line Test Boards [ D060124 ] ordered. They should be here within 10 days.
The cabeling was cleaned up a little bit yesterday morning. The upper back side is still massy.
Oplev sums of 240 days.
Since there have been various software/hardware activity going on (stack weighing, AUX laser PLL, computing timing errors etc etc), I decided to do a check on the state of the IFO.
You should wipe off the table cover before you take it off next time.
It is important to turn up the PSL encloure HEPA Variac voltage if you are working in there. It takes less than 10 minutes to reach lab condition.
Lab air count normal. It is not logged. I have a notebook of particle count on the SP table next to the Met One counter.
We may lost the UL magnet or LED
Furthermore, I believe we are losing more than 10% of the light due to this BS. The ASDC (which is derived from AS55 PD) level is down at ~110cts as the Michelson is fringing, while it used to be ~200 cts. I will update with a power measurement shortly. But I think we should move ahead with the plan to combine the beam into the IFO's AS mode as discussed at the meeting last week.
Is the 10% specified for P-Pol or for UNP? I contacted CVI about beamsplitters, since their website doesn't list a BS1-1064-90-... option on the website. They say a R=90% beamsplitter would be a custom job. The closest stock item they got is BS1-1064-95-2025-45UNP specified at R=95% for UNPolarized beams. They were kind enough to sent me the measured transmission curves for a recent lot of these, which is attached was uploaded to the wiki [Elog Police K: NO PROPRIETARY DOCUMENTS ON THE ELOG, which is public. Put it on our wiki and put the link here]. The figure is not labeled, but according to the contact Red is S-Pol and Blue is P-Pol, which means that this one actually has R=~90% for P, pretty much what we want. We'll need to buy two of these to make the swap in the setup.
Back to your original point: There's only a BS1-1064-10-2025-45UNP on the website, so unless we got these as custom items, the R for P-Pol is probably NOT actually 10%, just somewhere between 0% and 20%
4 std cataloge item fused silica BS1-1064-95-2025-45UNP
ordered today. They will arrive no later than July 13, 2018
The fardest I can go back on channel C1: Vac_N2pres is 320 days
C1:Vac-CC1_Hornet Presuure gauge started logging Feb. 23, 2018
Did you update the " low N2 message" email addresses?
I moved the N2 check script and the disk usage checking script from the (sudo) crontab of nodus to the controls user crontab on megatron .
Shruti and Sandrine received 40m specific basic safety training this morning.
This bad connection is coming back
We are getting ready to vent.
Steve and Aaron,
6 hrs vent is reaching equlibrium to room air. It took 3 and a half instrument grade air cilynders [ AI UZ300 as labelled ] at 10 psi pressure. Average vent speed ~ 2 Torr/min
Valve configuration: IFO at atm and RGA is pumped through VM2 by TP1 maglev.
Precondition: 4 days at atm. Atm5
HEPA tent used during the vent at ETMY It reduced partical count 10 fold of 0.5 and 0.3 micron particals. Atm6
New items in vacuum: Clean manual gate valve [Cetec made] from John Worden with 6" id....as it came from Hanford... [ Throttle able gate valve- TGV ] Atm3
( note: we have 3 more identical in the lab. The original intention was to use them for purging gates )
Optiform Au plated reflector , Induceramics heating elements, similar as existing Cooner cables and related lenses, hardwear. see 14078
OMC related item : none......... 14,110
The pumpdown is at 510 mTorr with RP1 & RP3 still pumping. Koji will shut it down the roughing later tonight. Tomorrow morning I will start the pumping by switching over to TP1 maglev.
Thanks for Koji and Gautam' help of the installation of the manual gate valve. Atm4 This will allow us to control the load on our Varian foreline D70 turbo TP3
The manual gate valve scan was clean. Atm1 TP1 was pumping on it overnight.
Pumpdown continued to hand over the pumping to TP1 maglev turbo
V1 was opened at P1 400 mTorr with manual gate at 3/4 turn open position as Magev at 560 Hz rotation.
Two aux fans on to hold tubo temps TP1 & TP3 . Atm3
This is the first time we pumping down from atm with ONE small "beer can" turbo and throttled gate valve to control load on small turbo forepump
The 70 l/s turbo is operating at 50k RPM, 0.7 A and 31 C, pumping speed ~ 44 mTorr/h at 200-400 mTorr range with aux drypump in the foreline of TP3
Watching foreline pressures and current one can keep opening gate valve little by little the so the load is optimized. It is working but not fast.
Let's keep small turbo at 0.8 Amp and 32 C max at this pumpdown.
The P1 pressure is 380mTorr. I allowed Gautam to use the full PSL power (~1W).
IFO P1 6e-4 Torr, manual gate valve is fully open
The annuloses will be pumped down tomorrow.
Valve configuration: vacuum normal, RGA and annuloses are not pumped
This is the first time we pumping down from atm with one small "beer can" turbo and throttled gate to control load on small turbo forepump
The 70 l/s turbo is operating at 50k RPM, 0.7 A and 31 C, pumping speed ~ 44 mTorr/h at 200-400 mTorr range.
Cold cathode gauge just turned on.