The crane inspection is scheduled for this coming Friday from 8-12
I wrote a small document on the application of LQG method to a Fabry-Perot cavity control.
jamie, nic, jenne, den, raji, manasa
We were doing pretty well with alignment, until I apparently fucked things up.
We were approaching the arm alignment on two fronts, looking for retro-reflection from both the ITMs and the ETMs.
Nic and Raji were looking for the reflected beam off of ETMY, at the ETMY chamber. We put an AWG sine excitation into ETMY pitch and yaw. Nic eventually found the reflected beam, and they adjusted ETMY for retro-reflection.
Meanwhile, Jenne and I adjusted ITMY to get the MICH Y arm beam retro-reflecting to BS.
Jenne and I then moved to the X arm. We adjusted BS to center on ITMX, then we moved to ETMX to center the beam there. We didn't both looking for the ETMX reflected beam. We then went back to BS and adjusted ITMX to get the MICH X arm beam retro-reflected to the BS.
At this point we were fairly confident that we had the PRC, MICH, and X and Y arm alignment ok.
We then moved on the signal recycling cavity. Having removed and reinstalled the SRC tip-tilts, and realigning everything else, they were not in the correct spot. The beam was off-center in yaw on SR3, and the SR3 reflected beam was hitting low and to the right on SR2. I went to loosen SR3 so that I could adjust it's position and yaw, and that when things went wrong.
Apparently I hit something BS table and completely lost the input pointing. I was completely perplexed until I found that the PZT2 mount looked strange. The upper adjustment screw appeared to have no range. Looking closer I realized that we somehow lost the gimble ball between the screw and the mount. Apparently I somehow hit PZT2 hard enough to separate from the mirror mount from the frame which caused the gimble ball to drop out. The gimble ball probably got lost in a table hole, so we found a similar mount from which we stole a replacement ball.
However, after putting PZT2 back together things didn't come back to the right place. We were somehow high going through PRM, so we couldn't retro-reflect from ITMY without completely clipping on the PRM/BS apertures. wtf.
Jenne looked at some trends and we saw a big jump in the BS/PRM osems. Clearly I must have hit the table/PZT2 pretty hard, enough to actually kick the table. I'm completely perplexed how I could have hit it so hard and not really realized it.
Anyway, we stopped at this point, to keep me from punching a hole in the wall. We will re-asses the situation in the morning. Hopefully the BS table will have relaxed back to it's original position by then.
Here is a two hour set of second trends of 2 sensors per mirror, for BS, PRM, ITMY and MC1. You can see about an hour ago there was a big change in the BS and PRM suspensions, but not in the ITMY and MC1 suspensions. This corresponds as best we can tell with the time that Jamie was figuring out and then fixing PZT2's mount. You can see that the table takes some time to relax back to it's original position. Also, interestingly, after we put the doors on ~10 or 20 minutes ago, things change a little bit on all tables. This is a little disconcerting, although it's not a huge change.
what's going on with those jumps on MC1? It's smaller, but noticeable, and looks like around the same time. Did the MC table jump as well?
more looking tomorrow.
But these jumps in the OSEMs are all at the level of 10-20 microns. Seems like that wouldn't be enough to account for anything; 20 microns / (pend length) ~ 50-60 microradians.
BS table and suspensions are fine.
Here's a plot of the BS, PRM, and MC1 suspension shadow sensor trends over the last 24 hours. I tried to put everything on the same Y scale:
There definitely was some shift in the BS table that is visible in the BS and PRM that seems to be settling back now. The MC1 is there for reference to show that it didn't really move.
Leo fixed an issue with the new nds2-client packages that was preventing it from retrieving online data. It's working now from matlab, python, and octave.
Here's an example of a dataviewer-like script in python:
from pylab import *
# channels are command line arguments
channels = sys.argv[1:]
conn = nds2.connection('fb', 8088)
fig = figure()
for bufs in conn.iterate(channels):
for buf in bufs:
the align script was run after the third lock here. it would have been interesting to see the arm powers in a 4th lock
Bulb went out ~10am today. Looks like the lifetime of this bulb was <100 days.
Steve: bulb is arriving next week
Bulb is replaced.
BL-FS300C-PH-LE was replaced after 2,904 hrs It did not explode this time. The 4 monts life period is actually pritty good because this is a $73. cheap bulb. The best-high priced warranty is 5 months.
PS: future option_bulbless laser projector
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This would give you everything you are requesting, plus a lamp-less design and 5yr warranty. Ground shipping would be free anywhere in the lower 48, and we would not charge sales tax on orders billing/shipping outside of AZ. If you have any questions or if you would like to order... just let me know!
I noticed this behaviour since ~Dec 20th, before the power failure. The bulb itself seems to work fine, but the projector turns itself off after <1 minute after being manually turned on by the power button. AFAIK, there was no changes made to the projector/Zita. Perhaps this is some kind of in-built mechanism that is signalling that the bulb is at the end of its lifetime? It has been ~4.5 months (3240 hours) since the last bulb replacement (according to the little sticker on the back which says the last bulb replacement was on 15 Aug 2017
Light bulb replaced.
Bulb replaced at day 110 We have now spare now.
I replaced the projector bulb. Previous bulb was shattered.
The control room's north west corner smelled like propane gas yesterday around 16:30
We all agreed that the smell was real and I called the safety office. I was told that they received 6 other calls from different parts of the campus.
The smell disappeared in about a half an hour.
Property tag found.
The major changes from the previous layout:
Does any part of this layout need a radical redesign?
I realized I had overlooked an important constraint in the layout, which is that the enclosure will have two supports that occupy some region of the table - these are denoted in blue in v3 of the layout (Attachment #1). I measured the dimensions for these from the existing Y-endtable. The main subsystem this has affected is the IR transmission monitors, but I've been able to move the photodiodes a little to accommodate this constraint.
I've also done the mode-matching calculations explicitly for the proposed new layout (Attachments #2 and #3, code in Attachment #4). While the layout was largely adopted from what Andres posted in this elog, I found that some of the parameters he used in his a la mode code were probably incorrect (e.g. distance between the 750mm lens and the ETM). More critically, I think the Gouy phase for the optimized solution in the same elog is more like 60 degrees. I found that I could get a (calculated) Gouy phase difference between the two PZT mirrors of ~81 degrees by changing the green path slightly, and making the two PZT mirrors Y7 and Y8 (instead of Y7 and Y11, for which the Gouy phase difference is more like 50 degrees). But this way the two steering mirrors are much closer to each other than they were before. Other misc. remarks about the mode matching calculations:
These changes also necessitated minor changes to the transmitted IR beampath and the Oplev system, but these changes are minor. I've also switched the positions of the AUX IR power monitoring PD and the fiber coupler as suggested by Koji. The shutter has also been included.
Rana advised that we put in a lockin-output matrix which will allow us to excite any combination of MC mirrors so that we can excite pure translations or rotations of the MC beam axis. This would require us to direct a lockin output into all the three mirrors simultaneously with a +1 or -1 as needed in the matrix..
Granite base 20" x 20" x 5" locations are on the CES side of our IFO arms: as shown ETMY_ south-west, ETMX_north-east, ITMX_south-east . No height limitation. This side of the tube has no traffic.
SS cover McMaster# 41815T4 (H) SS container cov
This is my interpretation of where Steve is proposing to place the seismometers (he wrote ITMX southwest, but I'm pretty sure from the photo he means southeast).
I think his point is that these locations are on the less-used side of the beam tube, so they will not be in the way. Also, they are not underneath the tube, so we will not have any problems putting the covers on/taking them off.
I am going to tweak the alignment of the beam into the AOM (before the PMC) tomorrow morning. If anybody has any objections to this, please raise a red flag.
Proposed alignment procedure:
1. Reduce PSL power to say 10%
2. Since the AOM is not on any sort of a mechanical stage, I will have to just play around carefully until I see a maximum power rejection into first order.
I am assuming that moving the AOM is not going to affect the input pointing because all these activities are happening before the PMC. So as long as I have the output beam from the AOM aligned to the PMC at the end, everyone should be happy.
I made the following change to correct the sign of the 126MON channel:
allegra:c1aux>ezcawrite C1:PSL-126MOPA_126MON.EGUF -410
C1:PSL-126MOPA_126MON.EGUF = -410
allegra:c1aux>ezcawrite C1:PSL-126MOPA_126MON.EGUL 410
C1:PSL-126MOPA_126MON.EGUL = 410
As we learned yesterday, the PSL laser power out put mechanical shutter is not working in the remote mode. It only works in local manual mode.
Do not rely on the MEDM screen monitor readout! The position is only changing on the monitor. The main beam must be blocked before the output periscope.
Some thoughts on what happened with the MOPA cooling.
Some unknown thing happened to precipitate the initial needle valve jiggle, which unleashed a torrent of flow through the NPRO. This flow was made possible by the fact that the cooling lines are labeled confusingly, and so flow was going backwards through the needle valve, which was thus powerless to restrict it. The NPRO got extremely cold, and most of the chiller's cooling power was being used to unnecessarily cool the NPRO. So, the PA was not getting cooled enough. At this, point, reversing the flow probably would have solved everything. Instead, we turned off the chiller and thus discovered the flaky start-motor capacitor.
Now we have much more information, flow meters in the NPRO and main cooling lines, a brand-new, functioning needle valve, a better understanding of the chiller/MOPA settings necessary for operation, and the knowledge of what happens when you install a needle valve backwards.
Pump down reached "vacuum normal" state. IFO _P1 pressure 1e-4 torr in 8 hrs actual pumping time
PSL shutter is opened.
Q checked the earth quake stops of SRM and we put the ITMY & BS doors on.
We stopped pumping just short of 3 hours at 320 Torr. Pumping speed was 2.7 Torr / min with partially closed RV1 and butterfly valve/
RP1&3 roughing pump hose is disconnected. Butterfly valve removed. The vac envelope is closed.
This is our second stop. I will be back this afternoon. IFO P1 3.5 Torr
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
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
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.
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
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
We are pumping down. The annuloses are below 10 mTorr
The vacuum gauges are not communicating with the medm so there is no plot available.
The main volume pumping is stopped at P1 = 220 Torr ( New SuperBee 174 Torr ) for overnight.
note: SuperBee was reading 791 Torr at atm and it was not set to 760 !
P1 IFO pressure is 1 mTorr, valve configuration: vacuum normal, annulosses are pumped, RGA is off, not pumped.
THANKS to Chris !
The shutters can be opened with high power.
No communication error message still exist.
I will reboot c1vac1 and c1vac2 to get gauge communication with medm tomorrow.
The pumpdown had stalled because of some ancient vacuum interlock code that prevented opening the valve V1 between the turbo pump and the main volume.
This interlock  compares the channels C1:Vac-P1_pressure and C1:Vac-PTP1_pressure, neither of which is functioning at the moment. The P1 channel apparently stopped reading sometime during the vent, and contained a value of ~700 torr, while the PTP1 channel contained 0. So the interlock code saw this huge apparent pressure difference and refused to move the valve.
To bypass this check, we used caput to enter a pressure of 0 for P1.
The pumpdown started at 9-12-2016
The IFO is at 5e-5 Torr vacuum normal after 73 day at atm.
ITMX needed to be freed and ETMY-UL is still misbehaving occasionally.
New pirani and cold cathode gauges added at this vent. They were baked at 100 C for 6 hrs under vacuum.
Go to the Vac Rack to read IFO pressure from the gauge itself when Vac. Monitor is blank as it is now !
P1 IFO pressure is 1 mTorr, valve configuration: vacuum normal, annulosses are pumped, RGA is not pumped.
IFO pressure 3.7e-5 Torr at new cold cathode InstruTech - Hornet
New items in vacuum:
1, ETMX sus tower with new baked sus wire, EP30-2 epoxied magnets, same at different locations also........ .......... and 2 ruby wirestandoffs.
2, First Contact cleaned arm test masses only. This technic was a 1st time use in our vacuum system.
3, 50 mm ID green glass baffles at the ends
4, witness mirrors at ETMX and ITMY (old oplev mirrors) We observed a very dusty system: sides of optics, towers and tables were wiped. Hepa tents used at Y arm and BS
5, new pirani, cc gauge and 1.5" right angle valve
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.
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