Sorry to say but MC1, MC2, MC3 and PRM face OSEMS are having the same problem of leaking IR into the sensors
The PMC was not locked for 11 minutes on this plot.
ETMY sus damping restored
This is a proposal to move WFSs such way that their reflected beam can be trapped.
Later ps: Nic will take care of the Gouy phase telescopes.
We have implemented an SR560-based ISS loop using the AOM on the PSL table. This is a continuation of the work in 40m:9328.
We dumped the diffracted beam from the AOM onto a stack of razor blades. This beam is not terribly well separated from the main beam, so the razor blades are at a very severe angle. Any alternatives would have involved either moving the AOM or attempting to dump the diffracted beam somewhere on the PMC refl path. We trimmed the RF power potentiometer on the driver so that with 0.5 V dc applied to the AM input, about 10% of the power is diverted from the main beam.
We ran the PMC trans PD into an AC-coupled SR560. To shape the loop, we set SR560 to have a single-pole low- pass at 300 Hz and an overall gain of 5×104. We take the 600 Ω output and send it into a 50 Ω feed-through terminator; this attenuates the voltage by a factor of 10 or so and thereby ensures that the AOM driver is not overdriven.
The AOM driver's AM input accepts 0 to 1 V, so we add an offset to bias the control signal. The output of the 50 Ω feedthrough is sent into the 'A' input of a second SR560 (DC coupled, A − B setting, gain 1, no filtering). Using a DS345 function generator, a 500 mV offset is put into the 'B' input (the function generator reads −0.250 V because it expects 50 Ω input). The 50 Ω output of this SR560 is sent into the AOM driver's AM input.
A measurement of suppressed and unsuppressed RIN is attached. We have achieved a loop with a bandwidth of a few kilohertz and with an in-loop noise suppression factor of 50 from 100 Hz to 1 kHz. This measurement was done using the PMC trans PD, so this spectrum may underestimate the true RIN.
A small followup measurement. Here are spectra of the MC trans diode with and without the ISS on. The DC value of the diode (in counts) changed from 17264.2 (no ISS) to 17504.3 (with ISS), but I didn't account for this change in the plot.
There is a small inkling of benefit between 100Hz and 1kHz. Above about 100Hz, the RIN is suppressed to about the noise level of this measurement. Below 100Hz there is no change, which probably means that power fluctuations are introduced downstream of the AOM, which argues for an outer-loop ISS down the road.
Atm #2 is in units of RIN.
I have disconnected the cable from the SR560 to LSC -ch8 for 15minutes this morning. It is moved from the floor to the top of the chambers as preparation for 40m tour. The SR560 seems to be overloading.
The ISS servo is off according to the MEDM screen. Why MC-T plot showing zero? The MC was happy yesterday.
PRM is aligned. IFO is not locked. It is just flashing, including arms. Olympus SP570UZ camera used without IR blocker. Note: PRM side OSEM does not show IR effect.
I will take more pictures with IOO IR blocked and HeNe oplev blocked tomorrow morning.
Can't we somehow hook up this camera to the MUX with the movie mode?
I think both the MUX and the sensoray are compatible with the color video signal.
Only the old CRT is B/W.
Watek 902H ccd with Tamron M118FM50 lens is hooked up to MUX Please be careful! In this set up the lens is close to the view port glass window!
The PMC power degrading on this 3 days plot. MC2 -T = 14,200 counts. C1:IOO-MC_TRANS_SUM can not be ploted in dataviewer. The MEDM screen has a valid number.
Initial pointing is not so bad (what does "not so bad" mean ???)
C1iscey comes and goes again.
Jamie, I think the computers know that you are away. c1lsc keeps going down.
The short time plots are correct.
Valve configuration: Vacuum Normal
Rack 1x6 is very noisy.
SunFire X4600 computer: FB (directly below Megatron) has it's yellow warning light on. It must be loosing one of it's fan bearings.
Jetstore's error message: IDE channel #2 reading error
Steve was trying to do something to it this morning, but I'm not exactly clear on what it was. Maybe that helped? Steve, can you tell us what you were trying to do this morning?
I was trying to repeat elog 9007 I did only get to line 2 of the Solution by Koji when Ottavia shut down, where I was working. This was all what I did.
Can't we somehow hook up this camera to the MUX with the movie mode?
I think both the MUX and the sensoray are compatible with the color video signal.
Only the old CRT is B/W.
PRM-BS & Faraday video ccd cameras covered as shown. These thin wall metalized ducts are perfect for blocking light in both direction.
They are very light and give you easy access to adjustment.
c1scy had frequent time-over. This caused the glitches of the OSEM damping servos.
Today Eric Q was annoyed by the glitches while he worked on the green PDH inspection at the Y-end.
In order to mitigate this issue, low priority RFM channels are moved from c1scy to c1tst.
The moved channels (see Attachment 1) are supposed to be less susceptible to the additional delay.
This modification required the following models to be modified, recompiled, reinstalled, and restarted
in the listed order: c1als, c1sus, c1rfn, c1tst, c1scy
Now the models are are running. CDS status is all green.
The time consumption of c1scy is now ~30us (porevious ~60us) (see Attachment 2)
I am looking at the cavity lock of TEM00 and I have witnessed no glitch any more.
In fact, the OSEM signals have no glitch. (see Attachment 3)
We still have c1mcs having regularly time-over. Can I remove the WFS->OAF connections temporarily?
Koji cleaned up very nicely.
The PRM sensors are no longer effected by IR. What changed? The MC still does.
Since the pointing has gone bad again, I went to the PSL to investigate. Found some bad things and removed them:
1) There was a stopped down iris AGAIN in the main beam path, after the newly installed mirror mount. I opened it. Stop closing irises in the beam path.
2) The beam dump for the IOO QPD reflection was just some black aluminum. That is not a real dump. I removed it. We need two razor blade dumps for this.
3) There was an ND filter wheel (???) after one of the PMC steering mirrors. This is not good noise / optics practice. I removed it and dumped the beam in a real dump. No elog about this ?!#?
The attached trend shows the last 20 days. The big step ~2 weeks ago is when Steve replaced the steering mirror mount with the steel one. I don't understand the drift that comes after that.
Today I also spent ~1 hour repairing the Aldabella laptop. Whoever moved it from the PSL area to the SP table seems to have corrupted the disk by improper shutdown. Please stop shutting the lid and disconnecting it from the AC power unless you want to be fixing it. Its now running in some recovery mode. Lets leave it where it is next to the PSL and MC1.
I steered the MC suspensions back to where they were on the trends before the PSL mirror mount swap and then aligned the PSL beam into it by touching the last 2 steel mounts. Once the alignment was good without WFS, I centered the beams on the IOO QPDs. If it behaves good overnight, I will center the unlocked beams on the MC WFS.
Please stay off the PSL for a couple days if you can so that we can watch the drift. This means no opening the doors, turning on the lights, or heavy work around there.
IOO pointing monitoring qpds received razor beam dumps on their refs.
The Pos QPD was rotated and recentered.
The Ang QPD was left untouched.
TREND plot of 23 days is attached.
Aluminum shield replaced by razor beam dump.
New razor beam dump installed to trap reflected beam of the input vacuum window.
Instrument rack power supplies checked and labeled at present loads.
The vacuum rack Sorensen is running HOT! Their is only 0.3A load at 24V There is plenty of space around it.
It is alarming to me because all vacuum valve positions are controlled by this 24V
The temperature went down to room temp with temporary fan in the back. Voltage and current are stable.
Regardless, it will be replaced early next week.
40m crew and visitor Holger Muller from Berkeley.
This is not a test. Life can be dangerous in the 40m Control Room.
The lamp lasted for 4,622 hours.
This time I purchased just the bare lamp itself . The housing doubles the price. The disadvantage of this technic that the lamp housing window can not be cleaned perfectly. Atm2 picture is exaggerating this spot.
However, It does not degrade the image quality.
It was a bad experience again with our vacuum system. The valves went crazy as we rebooted the computer. This was required for the swap in of a good 24V power supply.
The IFO was vented to 27 Torr through the annuloses, VA6, V7, Maglev,VM2 and VM1 (VC2 was open too)
I just opened the PSL shutter after a 4 hours pumpdown.
Condition: annuloses are not pumped, the IFO and the RGA are pumped as Atm2 shows
I will be here tomorrow morning to switch over to vacuum normal.
More details later
The recovery- pumpdown reached valve configuration vacuum normal at 20 hours, cc1 7.7e-6 Torr
Lesson learned: turn all pumps off, close all valves before you reboot ! like you would prepare for AC power shut down.
The date is correct on this monitor.
Last stored RGA scan data Dec 20, 2013
IFO pressure at CC1 5.8e-6 Torr
Valve configuration: Vacuum Normal, confirmable only by manual checking of position indicators and pressure gauge controllers readouts
Events of the power supply swap:
1, Tested 24V DC ps from Todd
2, Closed V1, VM1 and all annulos valves to create safety net for the reboot. Turbo pumps left on running.
3, Turned computer off
4, Swap power supplies and turned it on
5, Turning the power on of c1vac2 created caos switching of valves. This resulted in a air vent as shown below.
6, VM1 was jammed and it was unable to close. The IOO beam shutter closed and the IFO was venting with air for a few minutes. Maglev did an emergency shut down. TP2's V4 and TP3' V5 closed. RP1 and RP3 roughing pumps turned on, their hose was not connected as usual. The RGA shut down to protect itself.
7, Closed annulos valves, stoped the vent at P1 27 torr as the vacuum control was manually recovered
8, The Maglev and the annuloses were roughed out 500 mtorr . The Maglev was restarted.
9, The IFO pump down followed std procedure from 27 torr. VM1 was moving again as the pressure differential was removed from it.
Remember: next time at atm .....rough down the cryo volume from 27 torr !
The trend shows a big jolt to the MC1/3 pointing this morning at 8:30.
If not, we will have to put a 'no janitor' sign on all of the 40m doors permanently to prevent mops misaligning our interferometer.
I was taking pictures at the AP table at the morning and ETMX optical table after noon. There was no activity on the IOO chamber.
Look at the last 2 hours of Rana's trend plot. MC1 and MC2 sensor voltage started increasing.
I think it was a drift action.
IOO QPDs tested in dark, lighted and open PSL enclosure. The created temperature change 0.03 C has effect on monitoring in pitch.
Atm1, all lights off 10 min, PSL enclosure lights on 10 min, all lights off 15 min, open door # 11 at north east corner of enclosure ( HEPA filters are running at 30V ) for 10 min, closed-dark enclosure 15 min
dark 10, lighted 10, dark 15, open-dark 10 and closed-dark 15 minutes
Atm2, Pitch drift of 24 hours does not recover
I looked at IOO QPDs again. QPD_POS was clamped by one screw. Dog clamp was added on the unclamped side.
QPD_ANG chassis has no isolation to optical table..._POS has. QPD_ANG base was tightened also.
Both QPDs moved a little bit but I did not centered them. The spot sizes are 2-3 mm They should be smaller.
How ever, we still can not explane the pitch movement of the IOO beam
Razor beam dumps were labeled at the AP table.
The 40m roof was cleaned from leafs this morning.
I wonder what's drifting between the laser and the PMC? And why is it getting worse lately?
The PMC refl is bad in pitch today, and the transmission is only 0.76, rather than our usual 0.83ish.
I did a quick, rough tweak-up of the alignment, and now we're at 0.825 in transmission.
The PMC transmission continuously degrades. In order to see what is really drifting the laser output after PBS was sampled as shown.
IOO pointing is drifting in pitch. I'd like to use a QPD instead of the paper target to see if the Innolite output is stable. The idea is to move temporarily IOO-QPD_POS to this location
Three good days of IOO pointing: Friday, Sat and Sun What was changed? May be the clamping on Friday?
IOO vertical changes recovering as tempeture. IP is clipping at plastic enclosure of ETMY
NOTE: ANTS at the PSL optical table. I will mop with chemicals tomorrow if we see more.
The Osaka TG390MCAB maglev turbo pump's controller TC010M has passed the 40,000 hrs of operation. This triggered the " alarm" LED warning light to come on.
It is normal maintenance. Maglev TP-1 is running perfectly. Osaka will send us a loaner-controller that we can use while they do the std maintenance.
I'm thinking of ~ February to do this.
I do like to move IOO-QPD_POS temporarily to see that the feedback has anything to do with with the pointing.
GariLyn is using our green light on the west side of the PSL table. The green PDA36As were moved and the HEPA turned up to 60V
It looks like there was a 4.4 magnitude earthquake near Fontana, CA around 1:30am today. This tripped all of the suspension watchdogs, which Q has just now re-enabled.
Earth quake shake down yesterday Atm1
Atm2, today's shake
Steve noticed that the RGA was not logging data and that not all the correct connection lights were on, and he wasn't able to run the "RGAset.py" script (in ...../scripts/RGA/) that sets up the proper parameters.
I looked, and the computer was not mounting the file system. I did a remote shutdown, then Steve went in and pushed the power button to turn the machine back on. After it booted up, it was able to talk to the file system, so I started ..../scripts/RGA/RGAset.py . The first 2 times I ran the script, it reported errors, but the 3rd time, it reported no communication errors. So, now that the computer can again talk to the file system, it should be able to run the cronjob, which is set to take data at 4am every day. Steve will check in the morning to confirm that the data is there. (The last data that's logged is 22Dec2013, 4am, which is right around when Koji reported and then fixed the file system).
We are venting tomorrow. This give us an opportunity to fix sick vacuum controller computer. Jamie volunteered.
Remember to rough down cryo and ion pump volumes. Their pressure can be at 1 Torr range after years of accumulated outgassing. Without total valve controls it is dangerous to have these air pockets. Some of their gate valves can be leaking and that would explane the slower pumpdown speed.
There is BLANK VacControl_BAK.adl screen only.
I can move a valve by disconnecting it's solenoid power if it's position is normally open.
I will close V1 and check computer cable connections and move on with manual - hand disconnect ea valve to be moved into the right position for vent. Valve positions will be confirmed by looking manual indicators on valves.
The 40m vacuum envelope vent is completed with instrument grade air.
Valve configuration: chamber open, RGA is pumped through VM3 by TP3,
PSL output is stable.
We pushed the reset button of c1vac1 and c1vac2 and the vacuum screen is back.
First, we pushed the reset button of c1vac1 and pushed the one on c1vac2.
This did not bring c1vac2 up. We pushed the reset of c1vac2 again and now everything of the vacuum screen is back.
1, Reset works
2, Default values are lost. They actually reversed into open and turn on everything when power recycle c1vac1, c1vac2 or 24V dc power supply. This can vent the IFO in an event of power failure!
It's may be the time to go back to an isolated, vacuum controller only computer.
The present valve configuration at Atm1
a, all annuloses are vented
b, valve cables disconnected at: VC1 and 4 IP gate valves
c, the RGA is off and it is pumped by the Maglev through VM2
d, cryo pump is being roughed with TP3 It's outgassing rate was 25 mTorr / min
e, Roughing hose is disconnected
Please wet WIPE before opening chamber or optical table ! !
with methanol soaked kimwipes.
The Met One particle counter is located on CES wall, just behind ITMX chamber.
The numbers are not so bad, but have you ( ...a) asked the IFO lately?
There was 0.2 mW green at the X end.
The doubling oven temp was changed from 37.5 to 36 degrees C
Power at green shutter 3 mW The alignment was not touched.
Vacuum checks before pump down:
1, check intermittent contact issue in black relay box
2, reconnect cable to ion pumps and vent them to atm before pump down
3, repeat power shutdown-reboot at atmosphere
ETMY damping restored.
I checked the alignment one last time. The arms locked, PRM aligned, oplevs centered.
We went ahead and put the heavy doors ON. Steve is pumping down now!
The ion pumps were vented just before pumpdown and their gate valves were opened.
This is an effort to minimize a possible leak through their gates.
Is there a volunteer who goes home late and would close off the roughing? tonight
Pumpdown completed. IR shutter opened at P1 1 mTorr The block is still in the beam path.
Remember to protect MCR pd before crack up the PSL power.
The ion pump gate valves were just closed by cc1 triggered interlock
The cry pump was "regenerated" during the vent and it's outgassing rate minimized.
CC3 cold cathode gauge was replaced.
Valve configuration for week end:
1, VA6 disconnected to avoid accidental venting the IFO through the annulos
2, VC2 disconnected to insure that the cryo stays closed
3, RGA is not running, It's pressure limit 1e-5 Torr
Valve configuration: Vacuum Normal is reached in really 4 days if we do not count overnight rest of roughing.
VA6 and VC2 are reconnected. I'm turning on the RGA next
All 4 ion pumps were vented with air and pumped down to ~ 1e-4 Torr
Ion pumps gate valve control cables are connected and their pumps are disconnected.
The black relay box was tested repeatedly and it stopped misbehaiving.
We were at atmosphere for 13 days. Chamber BS, ITMX, ITMY and ETMY were opened.
Al foil "cups" were placed on the back side OSEMs of PRM.