State condition: Vac Normal,          CC1 ~8e-6 Torr

The IFO pressure peaked at  8.3 mTorr after 2days of not pumping.

 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.

[Koji, Jenne]

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.

 [Steve, Eric]

I've been helping Steve vent this morning. The following things were done (from Steve's logbook):

• Particle counts: 0.5 micron particles, 4200 counts per cubic ft
• Vertex crane drive checked to be ok
• Optical Levers set for local damping only
• Saved some screens
• PSL shutter and green shutters closed
• HV Off checked, JAM nuts checked
• Vac: Close V1, VM1, ans - VA6, open VM3 - RGA, cond: chamber open mode
• 8AM: VV1 open to N2, regulator set  to 14 psi
• 8:23AM: 35psi Instrument grade Air

(At this point, I took over the air canisters, while Steve made preparations around the lab. 

• 9:00AM: 2nd air cylinder, 14 psi 
• 9:40AM: 3rd air cyl
• 10:20AM: 4th air cyl
• 11:00AM: 5th air cyl

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.

 IFO P1= 1mTorr,   CC1 = 5e-4 Torr.  The IFO is ready for work. Be free to open the shutter and turn on HV

Jenne will double check the MC -REFL path for 1W power.  There is a manual block on the PSL table.

Atm1,  Pirani gauge at 9 h 10 min

Atm2, Pump configuration of pd#73 at 9h 35 min

 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

 The RGA was not effected by the short power outage.

VME crate  blew its fuse and the fuse housing is hard to access.

Steve and I managed to access the fuse in the vacuum VME crate, but replacing it did not bring it back up.  We decided to replace the entire crate.

We manually checked that the most important valves, VC1, VM1 and V1, were all closed.  We disconnected their power so that they would automatically close, and we wouldn't have to worry about them accidentally opening when we rebooted the system.

We noted where all the cables were, disconnected everything, and removed the crate.  We noted that one of the values switched when we disconnected one of the IPC cables from a VME card.  We'll note which one it was in a followup post.  We thought that was a little strange, since the VME crate was completely unpowered.

Anyway, we removed the crate, swapped in a spare, replaced all the cards and connections, double checked everything, then powered up the crate.  That's when minor chaos ensued.

When the system came back online after about 20 seconds, we heard a whole bunch of valves switching.  Luckily we were able to get the medm screens back up so that we could see what was going on.

Apparently all of the ION pump valves (VIPEE, VIPEV, VIPSV, VIPSE) opened, which vented the main volume up to 62 mTorr.  All of the annulus valves (VAVSE, VAVSV, VAVBS, VAVEV, VAVEE) also appeared to be open.  One of the roughing pumps was also turned on.  Other stuff we didn't notice?  Bad.

We ran around and manually unplugged all of the ION pump valves, since I couldn't immediately pull up the vacuum control screen.  Once that was done and we could see that the main volume was closed off we went back to figure out what was going on.

We got the medm vacuum control screen back (/cvs/cds/caltech/medm/c0/ve/VacControl_BAK.adl.  really??)  There was a lot of inconsistency between the readback states of the valves and the switch settings.  Toggling the switches seemed to bring things back in line.  At this point it seemed that we had control of the system again.  The epics readings were consistent with what we were seeing in the vacuum rack.

We went through and closed everything that should have been closed.  The line pressure between the big turbo pump TP1 and the rest of the pumps was up at atmosphere, 700 Torr.  We connected the roughing pumps and pumped down the lines so that we could turn the turbos back on.  Once TP2 and TP3 were up to speed, we turned on TP1 and opened V1 to start pumping the main volume back town.   The main volume is at 7e-4 Torr right now.

So there are a couple of problems with the vacuum system.

• Why the hell did valves open when we rebooted the VME crate?  That's very bad.  That should never happen.  If the system is set to come up to an unsafe state that needs to be fixed ASAP.  The ION pump valves should never have opened.  Nor the annulus valves.
• Why were the switches and the readbacks showing different states?
• Apparently there is no control of the turbo pumps through MEDM.  This should be fixed.

I connect belledona, the laptop at the vacuum station to the wired network, so that it's connection would be less flaky.

CLOSE CALL on the vacuum system:

Jamie and I disabled V1, VM2 and VM3 gate valves by disconnecting their 120V solenoid actuator before the swap of the VME crate.

The vacuum controller unexpectedly lost control over the swap as Jamie described it. We were lucky not to do any damage! The ion pumps were cold and clean. We have not used them for years so their outgassing possibly  accumulated to reach ~10-50 Torr

I disconnected_ immobilized and labelled the following 6 valves:  the 4 large ion pump gate valves and VC1,  VC2  of the cryo pump. Note: the valves on the cryo pump stayed closed. It is crucial that a warm cry pump is kept closed!

This will not allow the same thing to happen again and protect the IFO from warm cryo contamination.

The down side of this that the computer can not identify vacuum states any longer.

This vacuum system badly needs an upgrade. I will make a list.

PR1, PR2 and RP3 turned on for warming up for oil change. Oil changed with 3.2L of  MVT-19 fluid in each. This substitute for HE-175 will be used at the next oil change - it has 1E-6 Torr vapor pressure.

To finish this job tomorrow: 1, check oil creeping upstream  2, change air filter of air purge if pressure drops <350 mTorr  3, measure venting time of pump

 PSL shutter closed, manual block in place, HV turned off. P1 is at 200 Torr now.  Jenne is taking over here.

 Valves closed, 500 torr.  Steve will finish off Monday morning, then we'll take off doors and get to work.

 We are almost at atm.  P1 750 Torr,  We are slowly reaching equilibrium.

 The access connector was removed, BS and ITMY chambers were opened yesterday.

New one piece aluminum shell access connector installed. Jenne lowered the PSL out put into MC to ~100mW

 . Leybold D30A manual is here. Exhaust filter traps were drained. No oil creeping was found. The pump venting time is < 1 minute.

PR-2 needs new secu-valve. PR1 & 2 are in excellent condition.

 While I was doing the oil change of the roughing pumps I accidentally touched the 24 V adjustment knob on the power supply.

All valve closed to default condition. I realized that the current indicator was red at 0.2A  and the voltage fluctuated from 3-13V

Increased current limiter to 0.4A and set voltage to 24V     I think this was the reason for the caos of valve switching during the VME swap.

 I asked Jamie to read these docs so we can do some troubleshooting while at atmosphere. We have to have the all valve closed DEFAULT condition working-tested.

I'd like to reconnect all valves after this test so the state identification software could work, including interlocks.

Posted the following documents on 40m wiki.

http://www.ligo.caltech.edu/~ajw/40m/40mVaccum_T000054-00.pdf
http://www.ligo.caltech.edu/~ajw/40m/40mProcedures.doc 

https://dcc.ligo.org/DocDB/0015/D000338/000/D000338-00.pdf

I'm looking for IOO steering mirror power supplies. I found two so far: one at 1Y3 as Kepco  + 75V and one at OMC_North rack -150V

Are there any more? The OMC is off.

ANSWER: only one of the steering PZT can be driven, so see their power supplies

 The pressure is CC1 3e-4 Torr at 8 hours of pumping.  Status: vacuum normal

The IFO is ready for light

 It took 15 days to reach 1e-5 Torr

The RGA was turned on yesterday. The rga scan plotting was not working. Den wrote a Python script to log and plot because the Mathlab had trouble receiving data from our old c0raga.

It turned out that the Joe's log&plot system was working today. Thanks Den and Joe.

Here is the first rga scan.

 The 40m vacuum envelope is at atm    It took 4.5 hours at ~3 Torr/min speed. Atm1

What I did:

Turned PZT voltages off: 84.1V at OMC-rack location

                                           -  99V at 1Y3 location as PZT_pitch,

                                             56.6V KEPCO at 1Y3 location as PZT_yaw                                           

Took screen shuts of SUS_SUMMARY, yesterday,  Atm3

Turned off OPLEV _SERVOs, today , Atm2

Closed PSL_SHUTTER and green shutters at the ends

Set vacuum valves for vent position and opened VM2 for the RGA

 Koji, Manasa, Jenne, Jamie, Bob and Steve

Access connector removed this morning and work has began in the IOO chamber.  BE WARE OF ANTS !