An important rule during the in-vac work :
Do not change the incident axis of the X and Y green beams.
Because of the air flows and unusual pressure in the chambers, the DC alignment of the suspensions become less reliable in terms of the beam pointing reference.
The green beams will be considered as references during the vent.
The vacuum system is coming up to atm. The vent was started with slow N2 flow.
P1 at 750 Torr, Vent valve VV1 is left open to atm. It will reach equilibrium in an hour. The PSL power is not turned down yet. The beam path is blocked at two places inside the enclosure.
The low power 20 mW input MC can be locked tonight.
Next day's - Thursday notes:
We reached 760 Torr of atm in 8 hrs at 1.7 Torr/ min with 5 cylinders of instrument grade air.
Used 500 PSI of nitrogen to get to 20 Torr at first. This flow and the first cylinder of N2 has to be slower next time.
We did the following:
1, oplevs were centered on locked caveties 2 days ago
2, just before vent we rechecked arms pointing, they wre still locking
3,eloged strain gages and turned HVs off at PZT-steering at 1Y3 rack and OMC-PZT ps at 1X2 aux rack. They were actually off.
4,,checked jam nuts 6 places x 3
5, turned oplev servos off
6, eloged SUS summery page
7, checked particle counts at ITMY: 1 micron 300, 0.5 micron 3K, 0.3 micron 30K particles / cft-min. All three cranes were wiped 2 days ago.
8, blocked laser into IFO: main 1064 in 1.25W were blocked by manual 2 blocks on PSL table. The PSL output shutter was left open to be triggered by interlock at P1 3 mTorr. It did!
Aux NPRO-AP and green light input at both ends were blocked.
The RGA region is beeing monitored during the vent. This will tell us how clean the RGA itself is.
Jenne found a big scratch on the north vac door of ITMY. Fortunately it does not reach the inner annulos 0 -ring seal.
This is precisely what we have to avoid to preserve our vacuum system!
For some reason the workstation at the vac rack was off and unplugged. Nicole and I plugged its power back in to the EX rack.
I turned it on and it booted up fine; its not dead. To get it on to the network I just made the conversion from 131.215 to 192.168 that Joe had done on all the other computers several months ago.
Now it is showing the Vacuum overview screen correctly again and so Steve no longer has to monopolize one of the Martian laptops over there.
Cranes are checked and they are ready for lifting. At the east end will use the manual Genei-lift to put door on.
[Steve, Bob, Jamie, Kiwamu, Valera, Jenne]
The access connector is now in place, in preparation for pump-down. Tomorrow (hopefully) we will do all the other doors.
Jamie is modeling our next generation in-vac & clean room bonny suit that Jenne and myself already tested.
It is quite bearable with our traditional cleanroom beret-bouffant cap. Please use these in the future.
This will help to avoid the farther degradation of somewhat dusty 40m vac envelope.
It is the required dress code to enter the clean assembly room in the 40m.
We have small, med, large and x-large in stock. I'm getting larger sizes.
It will not allow certain people to climb inside the vacuum chamber in dirty pants.
The RGA back ground at day 29 of this vent.
Steve and Jamie: After Jamie checks the ITM free swingings, please put on the ITM heavy doors and start the pump! For real this time!!! Yeah!
Jamie and Steve
We closed ITMX and ITMY chambers and started pumping around 11am
What we did before:
1, turned off AC power to PZT Jena HV ps
2, checked jam nut positions
3, cheched single o-ring shims
4, closed psl out shutter
We are at 30 Torr of 7 hours of pumping with 2 roughing pumps.
Kiwamu will take over the rest of the roughing today. He will keep an eye on the pumping speed to be ~1-2 Torr/min and open up the manual RV1 valve if needed.
The present status is #3023 of "chamber open to vacuum open" mode and waiting the P1 pressure to drop to 500 mTorr
He will do the following to stop pumping at P1 = 500 mTorr
1, close V3
2, close RV1 with torque wheel
3, turn off PR1 & 3
4, disconnect metal hose between RV1 and PR3
I will start the Maglev tomorrow morning.
I stopped puming at 9:30 PM and the pressure in P1 is at 450 mtorr.
I followed exactly he procedure that Steve noted on his elog entry.
Here is a plot of the histroy of our pumping today.
1, close V3
Vacuum status: " vacuum normal" CC1 pressure 5e-5 Torr
Slow roughing through butterfly valve took 11 hours at 1-2 Torr/min speed. We had a leak at the metal hose connecting o-ring that became visible at 200 Torr.
The vacuum envelope pressure rose to 500 mTorr from 450 mTorr This is 50 mTorr leak plus outgassing over 11 hrs over night stop = 5 mTorr / hr
Atm2, Maglev pumpdown details. P2 and P3 are in the foreline of the Maglev. The pressure peaks at 4 Torr beacause the 3 drypumps have little pumpimg speed at this range.
External fan is turned on during this one hour period to prevent Maglev turbo from overheating.
Same things are happenning with the two small TP2 and TP3 pumps under load. Their foreline pressure peak at 1 Torr. They slow down to 45 K RPM from 50K RPM and warm up to 36-39 C
Precondition: 36 days at atm
RGA scan with maglev pumping speed at day 14 of the pump down.
The larger inserted box contains the tuning parameters of the SRS 200 amu RGA
APC Smart -UPS 2200 model: SUA2200RM2U batteries were replaced by compatible RBC43, 8x 12V5A
1, closed V1, VM1, annuloses: VASE, VASV, VABS, VAEV, VAEE and VA6
2, stop rotation of Maglev-TP1, waited to decellerate and turned off power to it
3, closed V4, stoped rotation of TP2, waited to decellerate and turned power off
4, opened VM3 to RGA that is still running
I will come in tomorrow 9-10am to restart pumping.
I failed to start Rana's favorit anciant desktop computer at the vac rack. He has to baby this old beast just a little bit more.
Vacuum status: Vac Normal was reached through Farfalla: Rga was switched back to IFO and and Annuloses are beeing pumped now.
V1 was closed for about a day and the pressure reached ~2.8 mTorr in the IFO. This leakrate plus outgassing is normal
The ref cavity 5000V was turned on.
The only thing that has to be done is to restart the RGA. I forgat to turn it off on Friday.
As it turns out Steve is not crazy in this particular instance: the vacuum computer, linux3 , has some issues. I can login just fine, but trying to open a terminal makes the CPU rail and the RAM max out and eventually the machine freezes.
Under KDE, I can open a terminal OK as root, but if I then try a 'su controls', the same issue happens. Let's wait for Jamie to fix this.
I was lucky to notice that the nitrogen supply line to the vacuum valves was leaking. Closed ALL valves. Open supply line to atm. Fixed leak.
This was done fast so the pumps did not have to be shut down. Pressurized supply line and open valves to
"Vac Normal" condition in the right sequence.
The foreline pressure of TP2 was 1.4 Torr this morning. This drypump worked well for ten months.
Recently rebuilt drypump with new seal was swapped in.
This is how you do it: close V1, V4 and turn off TP2. Replace drypump and start up TP2
Set pump speed to 50 K rpm and open V4 to TP1 Note that the Maglev was not turned off because V4 was closed off only 5-10 minutes.
Open V1 the status is Vac Normal.
TP2 is rotating at 50K rpm, current pick up 0.2A, the temp is 26C and its foreline pressure 33 mTorr
The vacuum is ready for no AC power for 1 hr on Sunday morning at 10am
I did the follwing:
Closed V1, stopped the rotation of TP-1 maglev, waited till it reached 0 Hz_ rpm and turned it's controller off.
Closed V4 and stopped TP-2 rotating
Closed all annuloses and VA6
Closed VM1 and opened VM3 This means the RGA is being pumped by TP3. RGA is running in background mode. V5 will close instantly as the AC will be turned off.
VAC STATUS: IFO envelope and annulosses are not pumped. P1 pressure will reach 5-6 mTorr by Sunday morning.
The PSL output shutter will be closed by the interlock at 3 mTorr
Kiwamu will turn off Piezo Jena PZT power supplies and computers Saturday.
I will be here around 1pm Sunday to star pumping. I will need EPICs MEDM running by than.
State condition: Vac Normal, CC1 ~8e-6 Torr
The IFO pressure peaked at 8.3 mTorr after 2days of not pumping.
We tried not to open chambers above 10,000 particles of 0.5 micron cf/min
New items going in: 2 rasor beam traps, 5 badly oxidized old silver plated setscrew with spring loaded tips......to be replaced in the future, viton tips for eq screws....some are lose, gold plated allen wrench installed at ITMX bottom, reglued magnet on ITMX
Bad hardware things found: nylon ball "locking elements" on OSEM locking set screws with screwdriver slot, lose 1064 nm filter on OSEM pd
40m - pumpdown 71- maglev pumping speed - at day 276........all normal
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 4 hrs vent plot at 3 torr/min rate.
Nitrogen was used from 1e-6 torr to 35 torr at intake pressure 14 PSI
The rest was filled with 5 cylinders of Instrument Grade Air at intake pressure 14 PSI
We can start opening chamber at 3 pm today
[Yuta, Koji, Jamie]
We went into ITMX chamber to inspect the situation there. We looked for clipping and flipping at PR2, and found none, although we noticed that the beam at PR2 looks a little clipped.
We then went back into the BS chamber and took a closer look at the beam incident on PRM, and the situation with PR3. The PRM incident beam looked a little clipped, which we expected from the PR2 observation. But the beam looks well centered on PRM and PR3. As best I could tell the beam is reflecting off the front surface of PR3, as expected.
Looking at the beam around MMT1 and PJ2 (the second PZT on BS), we could tell that the beam incident and reflected off of MMT1 looked round, where as the beam incident on PJ2 looked clipped. Using my tallness super power I was able to reach into the IMC chamber and confirm that the beam going from MMT1 to MMT2 clips fairly badly on the edge of the Faraday. Koji speculates that this is the result of a misalignment of the PSL output beam into the MC. In any event, it's not clear how this would be the cause of our PRC woes.
We decided to close up for the night, and let Yuta work on aligning PRMI. We need to figure out what the heck to do now.
We've been watching the input power reduce, from 18 mW initially when we first went in, to about 5mW now. It seems to be leveling out now. It's unclear what would have been causing it. Drift of the input polarization?
Vacuum Normal State is reached in 9 hours. CC1 = 2e-5 Torr
Aux dry pump #3 is still running. The RGA is not pumped yet.
I'm looking for some movement indicators of the vent-pump down events.
I can not understand what really happened here with CC1 gauge or there was really a pressure glitch.
attachment 1, pump down day 3 with 4th of July fireworks in the lab
attachment 2, before and after vent in 9 days
TP2 dry_pump was changed at intake pressure 982 mTorr at 84,889 hrs This seal hold up for one year.
The rebuilt pump seal performing well at 28 mTorr
Our cold cathode 423 gauges are 10 years old. They get insulated by age and show no ionization current. We should replace them at the next vent. I'm buying 4 at $317ea
We have two CC1 gauges at the pump spool. One is in vertical position and the spare is in horizontal. Today I switched the cable from vertical to horizontal CC1
This one is reading higher pressure. It is an old dirty gauge. It may trigger the RGA protection when it's reading goes above 1e-5 torr
The real pressure is 2e-6 torr
cc1h spikes closed VM1 last night. VM1 is opened.
The power outage did not have any effect on the vacuum system. I had to open VM1 to the RGA because of flaky CC1 cold cathode gauge fluctuations.
We are running on the vertically positioned CC1 again.
Note: rga scans with closed VM1 are back ground scans.
Vacuum related work at atmosphere:
Atm1, Check all chamber dog clamps tightness with torque wrench,
Atm2, Replace old, black molibdenum disulfite bolts -nut with new silicon bronze nuts and clean SS bolts.
Atm3, Replace CC1 cold cathode gauges: horizontal and vertical.
Steve, do not vent tomorrow morning! We are still not prepared, and will not finish the preparation tonight. Hopefully we can finish the prep tomorrow, and then vent Tues.
Things we need to do before the vent:
MC spots centered [Jenne, tonight]
Use PZT2, BS to hit ~center of ETMs.
Realign arms, measure spot positions.
Make sure BS, ITMs are good - we want a good AS spot since we'll likely have to adjust some AS optics while we're inside
Insert attenuation optics, recover MC trans by rotating PBS cube to translate beam slightly
RGA scan, Maglev pumping speed at day 56
CC1 is dying. CC4 is real.
I have turned of the high voltage supplies for PZT1 and PZT2. The OMC PZT high voltage supplies were already off, since we aren't really using them currently.
I have closed the PSL shutter, but have not put in a manual extra beam dump yet.
All systems go for vent!
Steve - EricQ will be here around 8am to help with the vent.
I've been helping Steve vent this morning. The following things were done (from Steve's logbook):
(At this point, I took over the air canisters, while Steve made preparations around the lab.
With the 5th cylinder, we began approaching 1 atm, so we slowed the regulator down to 5psi. Around 750 torr, Steve opened VV1 to air.
According to Steve, we will be at atmospheric pressure at ~12:30pm.
ANTS ALERT please watch out for ants. We have them in the control room.
I tightened as many of the dog clamps on the bottom of the BS, ITMX and ITMY chambers as I could find. I used a torque wrench at 45 ft-lbs. Some of the bolts of the dogs were too long, and I couldn't find an extender thing to accommodate the bolt so I could reach the nut. None of the bolts moved that I was able to reach.
Steve, we're not doing final final alignment today (we will do it tomorrow), so please go around and double-check my work by checking all of the dogs first thing in the morning. Thanks.
Almost all chamber dog clamps on the floor checked. There are a few exception where it is impossible to to get to the nut.
Only the OOC nuts turned little bit. So our elastomer discs are holding up well. This means that the chamber anchoring to the floor is good.
We really need something better to replace the access connector when we're at air. This tin foil tunnel crap is dumb. We can't do any locking in the evening after we've put on the light doors. We need something that we can put in place of the access connector that allows us access to the OMC and IOO tables, while still allowing IMC locking, and can be left in place at night.
It is in the shop. It will be ready for the next vent. Koji's dream comes through.
Can we see the full design? If we can't lock the mode cleaner with this thing on then it's really of no use. We want it to be equivalent to the light doors, but allow us to keep the mode cleaner locked. That's the most important aspect.
It also needs to be wide enough that the MMT beam can go through, so that we can not only lock the MC, but also work on the rest of the IFO.
[The 40m Family]
The access connector and all heavy doors are back on.
Jamie put the regular viton EQ stops back on PRM, since he had to adjust the distance between the EQ stops and the PRM anyway. Jamie also waved an IR card near the IPANG steering mirrors in ETMY, but it was not possible to take a good photo. Jamie certifies that the beam is centered on both of those 2 optics.
I have centered IPPOS and IPANG QPDs.
All oplevs need a little realignment, especially ETMY, which had it's lens removed (Rana has a Wall of Shame photo of this, which is why it was removed by him). Steve will look into this tomorrow, after he starts pumping.
I have turned off all PZT high voltage supplies for in-vac PZTs: The input PZTs, the output PZTs, and the OMC PZTs (which weren't on, but I confirmed they were off).
I have also prepared the 3 low-power items for high power: MC refl's path was changed back to regular BS, AS camera was moved to its nominal position, and IPPOS has its ND filters back. MC refl and the AS camera will need to be realigned once we're actually at high power tomorrow afternoon.
Long vent, but good work everyone.
The IFO will be at atmosphere overnight. The annuloses are pumped down. The access connector jam nuts are tightened to 45 ft/lbs
Actual pumpdown will start tomorrow morning.