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 !

The COVAC_MONITOR.adl was changed. Ion pump labeled as disconnected means: ion pump controller power turned off and ion pump gate valve control connection disconnected.

RP2 roughing pump labeled disconnected means:  hardware  disconnected.

The actual operational, valve control screen has not been changed yet.

Reminder: I will be on vacation next week. We would have to put the access connector in tonight if I'm pumping down Friday, tomorrow.

 RGA background with VM2 open to Maglev at day 37

Note: The PAN gauge of the  annulos is at atm.  Please do not vent this 200 ft long annulos line when you venting the annulos of a chamber. The chamber annulos should be closed off to this long 2"  OD. pipe before you vent the annulos of a chamber.

CP Stat 100  sheet-covers were replaced by clean ones on open chambers BS, ITMX, ITMY and ETMY this morning.

Try to fold the sheets such way that the clean side is facing each other, so they do not accumulate dust.

[Steve, Yuta, Koji]

The ETMX heavy door was removed.

[Steve, Manasa, Jenne, Sendhil, Evan, Yuta]

We put heavy doors on ITMX/ITMY/BS chamber and started pumping down from annulus.

What we did:
  1. Replaced POP55 with AS55 back, because it was not broken.
  2. Centered on AS55, REFL55, REFL11, POPDC PD.
  3. Tried to lock PRMI, but I couldn't lock even MI stably for more than 1 min. I believe this is because it was noisy this morning. But I checked again that REFL/POP/AS beams are coming out without clipping and we have some error signals.
  4. Noticed AS beam has less range in left (on AS camera), so we tweaked OM4 a little to make more room.
  6. Took pictures inside ITMX and BS chambers
  7. Put heavy doors on ITMX/ITMY/BS chambers.
  8. Started pumping down annulus.
  9. Recentered IPANG/IPPOS and oplevs on their QPDs.

POP, REFL, AS:

 We are pumping down with RP1 & RP3 oily roughing pumps at 3 Torr/min speed. The butterfly valve was just removed.

The PSL shutter is open to vacuum at ~100  mW 1064 nm. The inter lock should close it at ~5 mTorr.

Rana will shut down pumping tonight.

He will close V3 from screen, close RV1 valve with torque wheel, turn off roughing pumps and disconnect hose between RV1 and roughing pumps.

I will restart pumping early morning tomorrow.

[Rana, Yuta, Koji]

21:05 at the pressure of 10torr
V3 closed. RV1 manually closed. RPs were turned off. And the bellows between RV1 and the rughing pumps are disconnected.

 Pump down is restarted after 10.5 hrs stop overnight.

 IFO   P1 pressure is 1 mTorr.  It is ready for high power light.

The Maglev took over the pumping at 500 mTorr

 All normal, IFO pressure 1.5e-5 Torr

RGA is pumped by TP-3 in back ground mode.

 Atm1, RGA background scan with TP3 pumping at day 7

Atm2,  IFO  CC1 = 1.1e-5 Torr at day 8

 Vacuum valve VM3 closed and VM2 opened, it switched the RGA to IFO scanning mode. CC4 = 3.5e-6 Torr

TP3 is pumping on the annuloses, their pressures are 1-3 mTorr

Vacuum condition reached the state of  Vacuum Normal. The MEDM screen "Current State" channel does not work because we disconnected some valves after the VME swap CAOS

Note: TP1 Maglev performance on Atm2  CC4 = 4e-9 Torr when VM2 valve was open

TP3 turbo pump's dry-foreline pump was replaced.

How to do it:

The pump should be replaced when it's performance  <1.0 - 1.3 Torr

Set up valve configuration as shown at Atm1: close in this order VAEE, VASV, VABS, VASV, VASE, VA6 and V5,

Turn TP3 off at it's controller in the rack. Wait till is stops, so you can read 760 Torr at TP3 foreline gauge

Disconnect intake, exhaust vacuum seals and replace pump. Reconnect vacuum fitting and start it up.

Confirm operational details on the front of the controller: 50 K_RPM, 0.2A and <100 mTorr

Reset valves in reverse order

PS: the average life of the tip seal on the Varian SSH-110 dry-pump is about 1 year

      This pump " ser LP1007L556 " seal  made new record of 668 days: thanks to Bob Taylor who is replacing these seals

 Pumpdown 75 - Maglev - day 12

Precondition: 66 days at atm, installed TIP-TILTs with coils that  replaced PZT-Jena input steering

Optical quality 6.5" OD window specs and quotes for vacuum view ports and optical table enclosure are on the 40m wiki_ Aux Optics page.

We have just received a very good quote #2  from Cascade  Optical.

 Vacuum normal condition at pumdown day 100

 Pumpdown 75, vacuum normal condition at day 144

Thanks for the good preparation.  IFO pressure P1=20 Torr

 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.

We will open the BS and ITMY doors first thing tomorrow morning. I plan to try to be in around 9 am. The first order of business will be to flip the folding mirrors that are not currently flipped (SR2, SR3, PR3).

 Jenne, Annalisa & Steve

 Manasa, Eric, Evan, Koji and Steve,

Access connector removed in order to complete alignment. Light aluminum with acetate windows AC installed.

Prior to the access connector removal, Manasa and I aligned the IFO mirrors.
The arms were locked and aligned by ASS.

We have been using Air Liquide Instrument Grade Air for venting the 40m vacuum envelope. It is no longer available.

The replacement is Alphagas 1, total hydrocarbon <0.1% ppm

LINK TO Alphagaz

Air Liquide > ALPHAGAZ™ Specifications

ALPHAGAZ™ Specifications

Because each analytical application is sensitive to critical impurities that can affect your results, tests in our research center and analyzer manufacturers' studies confirm that the main impurities are moisture, oxygen and hydrocarbons.

Based on these critical impurities, Air Liquide has developed ALPHAGAZ™ brand with a Maximum Impurity Level (H₂O, O₂, C_nH_m).

• The Maximum Impurity Level is the same across the whole product range. This constitutes a guarantee of quality with regard to major critical impurities and contamination tracers. ALPHAGAZ™ 2 offers an even greater guarantee in terms of purity (CO, CO₂, H₂).
• The Minimum Total Purity is a prerequisite for product quality, but we do not stop there: Air Liquide selects and controls its gas sources by defining specifications regarding impurities that are critical for your analysis or application.

 RGA background at day 12 of this vent . The maglev is pumping on the rga through VM2

 The pumpdown has started at 8:38am

Manasa was here to confirm good alignment of the IFO

Inner jam nuts of AC bellow were torqued to 45 ft/lbs and   door nuts were check on opened chambers.

Annulos were roughed down to 500 mTorr

Oplev servos turned off, PSL and green shutters closed before pumpdown started

 IFO  P1=1mT PSL shutter is opened