AA filter box was removed and modified at 1Y7 today. The -5V power supply was current limited when I plugged it back in. It was removed for medical attention.
NO PEM channels available! because of this.
D68L8EX-850Hz filter chips were removed and bypassed-shorted as Rana's entry on March 17, 2006 in old elog.
This unit is still has a short somewhere.
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.
The south end of IFO room 104 was reshuffled. The flow bench was moved all the way to the south end to create more room for the crane reach. The old large drawing cabinet was moved under the vacuum tube.
The new clear view through Acrylic-plexyglass cabinet is anchored. It has powder finished coating so it will not out-gas too much.The back side shelf mounting holes are sealed off with kapton tape. The doors still needs some gaskit seals.
I tried to understand what part of the signal is corrupted while passing through a digital straight line without any filters. From here we can figure out what precision is used.
I analysed coherence between C1:SUS-MC3_LSC_EXCMON and C1:SUS-MC3_LSC_OUTMON without any filters between them.
I did the simulation in Matlab using single and double precision. Basically, I took a random signal, made some operations with it to obtain some digital error:
signal1 = randn(1e6, 1); signal2 = randn(1e6, 1); signal3 = signal1+signal2; signal4 = signal3 - signal2;
Then I plotted coherence between signal1 and signal4 that are actually the same signal but signal4 has some digital error. This was done both for single (left red plot) and double (right blue plot) precision.
From here we make a conclusion that C1:SUS-MC3_LSC_EXCMON and C1:SUS-MC3_LSC_OUTMON has single precision. The signal might be converted from double to single in the dtt tools but if dtt works with double precision then the problem is with signals.
1X1 is strain relieved in the back. I will use similar approach on the rest of the racks .
I strain relieved RF cables labeled 33 MHZ LO and 166 MHZ to EOM at 1X2 This is a temporary setup for the 11 MHZ
The coax N bulkheads connectors are mounted on the plastic front panel now.
[Koji, Osamu and Kiwamu]
We found that the ETMX free swinging spectra showed a strange resonant frequencies.
We are going to inspect the suspension today.
In a ideal case the SOS (Small Optic Suspension) is supposed to have the following resonant frequecies.
(Although we didn't carefully identify which corresponds to which)
f_POS ~ 0.98 Hz
f_PITCH ~ 0.66 Hz
f_YAW ~ 0.8 Hz
f_SIDE ~ 0.99 Hz
However ETMX showed the following resonant frequencies.
f_POS ~ 0.91 Hz
f_PITCH ~ 0.7 Hz
f_YAW ~ 0.93 Hz
f_SIDE ~ 1.0 Hz
Especially f_YAW looks pretty high. Also the others are not at the right frequencies.
So we are suspicious that something wrong is happening on the ETMX suspension.
I noticed that ASDC level changes depending on the angle of ITMY when trying to take some data for loss map of YARM. We finally found that ASDC level behaves strangely when the angle of ITMY in yaw direction is varied, as you can see in Attachment 1. Now, AS port recieved only the reflection of ITMY.
NOTE: This behavior indicates that angular motion could couple to length signal in AS port.
Koji suggested that this behavior might be caused by interference at SR2 or SR3 between main path light and the light reflected by the AR surface. By rough estimation, we confirmed that this scenario would be possible. So it would be better to measure AR reflection of the same mirror to ones used for SR2 and SR3 in term of incident angle.
Ed by KA: This senario could be true if the AR reflection of teh G&H mirrors have several % due to large angle of incidence. But then we still need think about the overlap between the ghost beam and the main beam. It's not so trivial.
One possible explanation of this behavior is simply poor centering of the AS beam on AS55 (whose DC level provides ASDC, if memory serves me correctly).
I misaligned ETMY, and moved ITMY through its current nominal alignment while looking at the POYDC and ASDC levels.
In both pitch and yaw, the nominal alignment is fairly close to the "plateau" in which the AS beam is fully within the PD active surface. I.e. it doesn't take much angular motion to start to lose part of the beam, and thus introduce a first order coupling of angle to power. (Look at the plateaus at around -2min and -0.5min, and where the rapidly changing oplev trace crosses zero)
Furthermore, POYDC seems to be in some weird condition where it is actually possible to increase the reported powerwhen misaligning in pitch, but somehow there is more angular coupling in this state.
In any case, I would advise that the POY11 and AS55 RFPDs have their spots recentered with optics in their nominal aligned states. In fact, given how we found REFL11 alingment to be less-than-ideal not so long ago, all of the RFPDs could probably use a checkup.
It wasn't fully mentioned in ELOG 11814.
We checked the PD first and this behavior didn't change after the realignment of the AS55PD.
Yutaro confirmed that this effect is happening in the vacuum chamber.
I did additional tests for the strange behavior of ASCD. ETMY, ETMX and ITMY were misaligned so that only light reflected by ITMX went into AS port. I had done similar measurement before with ITMY YAW varied.
Attachment 1 shows how ASDC level changed when ITMX PIT varied.
Attachment 2 shows how ASDC level changed when ITMX YAW varied.
Attachment 3 shows how the power of light measured by a power meter just after the AS view port varied when ITMX YAW varied.
Comparing 1 & 2, we can say that this behavior is not unique to YAW direction.
From 2 & 3, we can say something strange is happening inside the chamber.
To check if the strange behavior of ASDC is caused by SR2/SR3 or not, I did the following measurement:
ASDC measures the power of the light reflected by ITMX. POXDC measures the power of the light reflected by ITMX and SRM successively. Then I varied the angle of ITMX in YAW direction and compared the behaviors of ASDC and POXDC.
The results are shown in Attachments 1-3.
As you can see in these figures, the strange up-and-down behavior appeared ONLY in ASDC. Therefore, the cause of this behavior exists between AS table and SRM (I had confirmed that the angle of SRM did not affect ASDC).
And this behavior is fringe-like, as can be seen in the figures (there seems to be 3 "peaks" and 2 "valleys"), so the cause could be interference between main path and not good AR reflection at a mirror after SRM before AS table (I suspect a mirror is flipped mistakenly).
While walking down to the X end to reset c1iscex I heard what I would call a "rythmic squnching" sound coming from under the turbo pump. I would have said the sound was coming from a roughing pump, but none of them are on (as far as I can tell).
Steve maybe look into this??
In order to block stray beams, I have put some beam dumps and razor blades on the PSL table.
There were three undesired spots in total. I found two spots on the south side door of the PSL room, close to Mach-Zehnder.
Another spots was on the middle of the north door. Now they all are blocked successfully.
STS readout box seems to be partly broken. I've terminated inputs from the seismometer and measured the output. I could not do this for vertical channel because it outputs 7 V DC + 500 mV AC signal. All the switches work fine, 5 V DC is indeed shown when auto zero, calibration, 1 sec resp, sig select are enables. The box has AC power supply that seems to work ok, all measured DC values are equal to the labels. Something is wrong with amplification.
I've turned off the power of the STS-2 readout box as it provides outputs with ~10 Volts DC offset! AA filter box works in the range -2 +2 Volts, so we do not have any useful information anyway. I'll adjust the mass positions in the seismometer.
We have 2 sts-2 readout box - pink and blue. Pink outputs 12 DVC - this a problem of amplifier. This box has a rectifier (the box works from AC power) and an amplifier for velocity channels. Mass positions, calibration channels are connected by a wire from input to output. The amplifier for velocity channels does not work properly, so I connected velocity channels directly to the output - the signal from sts-2 is large enough even without amplification. When I plugged sts-2 to pink readout board, on the velocity output I saw ~4 VDC. Sts-2 was needed to be recentered. I pressed AUTOZERO command, but this did not work out. Before I had checked that this readout box indeed gives an autozero logical signal - 5VDC for ~2 sec. I think it does not provides sts-2 with enough current, seismometer needs 0.1 A in autozero regime.
Blue readout box after switching it to 1 sec regime and zeroing sts-2 started to output reasonable signal for gains = 10. I tried gains = 100, X velocity channel started to output noise. Now the gain is 10 and the response is 120 sec. But at least this box works. Still performance is not clear as well as noise level. To determine this I've put sts-2 to isolation box.
After I've put Guralps in the isolation and waited for a couple of days, Guralp noise has been improved a little more.
We couldn't scan the Y arm for 1FSR last night because the ALS servo breaks while sweeping.
We thought this might be from the amplitude fluctuation of the beat signal. The amplitude of the beat signal goes into the beatbox was about -5 dBm, which is not so enough for the beatbox to get good LO. So, we put an amplifier (and attenuators) and the amplitude became +1 dBm. The range beatbox can handle is about -3 dBm to +3 dBm, according to our calculation.
This increased stability of the lock, and we could scan the arm for 1FSR. Below is the plot of scanned ALS error signal (blue), Y arm IR PDH signal (green) and TRY (red).
For each slope, we can see two TEM00 peaks, some higer order modes(may be 01, 02, 02) and sidebands (large 11MHz, small 55MHz?).
We couldn't scan for more. This is still a mystery.
Also, we need to reduce residual Y arm length fluctuation more because we get funny TRY peak shape.
For C1:ALS-BEATY_COARSE_I_IN1, 1 count stands for 0.21 nm(see elog #6817). We sweeped 4000 peak to peak in 50 sec. So, the scan speed is about 17 nm/sec.
This means it takes about 0.06 sec to cross resonant peak.
Cavity build up time is about 2LF/(pi*c) ~ 40 usec. So, the scan is quasi-static enough.
Characteristic time scale for the Y end temperature control is about 10 sec, so Y end frequency is following the Y arm length change with temperature control.
Currently, sampling frequency of DQ channels are 2048 Hz. This means we have 100 points in a TRY peak. I think this is enough to get a peak height.
- Reduce RMS. We are trying to use a whitening filter.
- Find why we can't scan more. Why??
- ETMY coil gains may have some unbalance. We need to check
- Characterize Y end green frequency control. Koji and I changed them last week (see elog #6776).
- Calculate positions of RF SBs and HOMs and compare with this result.
Tried the script 3 times and it didn't come back. Pkill'd and then scripted. That worked.
Been non-functional for 3 weeks. Anyone else notice this? images missing since ~Sep 21.
I've re-submitted the Condor job; pages should be back within the hour.
Summary pages will be unavailable today due to LDAS server maintenance. This is unrelated to the issue that Rana reported.
Nice PSL summaries from LHO:
[Jamie, Jenne, Suresh, Steve, Koji, Kiwamu]
We got two green beams coming out from the chambers !
Summary of today's invac work :
- removed the access connector and the BS north door
- realigned the X and Y arm to the green beams.
- installed a HWP on the ETMY table to rotate the polarization of the green beam to P.
- repositioned the first periscope on the BS table.
- repositioned the second periscope on the IOO table.
- steered some green mirrors on the IOO and OMC chamber to let the Y green beam come out to the PSL table.
- installed a PBS in front of the first periscope to spatially overwrap two green beams.
- adjusted the incident angle of the PBS to maximize the power of the Y green beam, which is transmitted through it.
- steer two mirrors on the BS table to align the X green beam
- installed two beam dumps, one is near the PBS to eliminate a ghost in the X green beam, and the other is on the back side of IPPOS/ANG pick off window.
- closed the doors.
When steering the final green mirror on the OMC table, accidentally we changed the alignment of the MC incident mirror.
So the alignment of the incident beam going into MC has changed, and we haven't re-aligned it yet.
During we were installing the PBS on the BS table, we found that the allowable incident angle for the Y beam is about ~ 55 deg, which maximizes the amount of the transmitted Y green.
Since the PBS had been considered to be 45 deg incident in our optical layout, this required several modifications in the green mirrors.
To have a clear X green beam path going into the PBS, we had to slide the PBS and periscope to the West.
The periscope is now sitting on the very edge of the BS table, and in fact ~ 20% of the bottom plate of the periscope is already sticking out.
Also since 30% of the area of the PBS's post is on a hole, which is somehow for the stack, we had to use three dog clamps instead of a folk clamps to make the contact tight.
[Rana / Jenne / Kiwamu]
The ETMY suspension tower is currently sitting on the north side of the table for some inspections.
The adjustment of the OSEMs is ongoing.
(What we did)
+ Taken out two oplev mirrors, Jamie's windmill and a lemo patch panel.
+ Put some pieces of metal as makers for the original place
+ Put some makers on the distance of dLY = -25.49 cm = -10.04 inch from the original place (see the 40m wiki).
The minus sign means it will move away from the vertex.
+ Brought the ETMY suspension tower to the north side to do some inspections
+ Did some inspections by taking the noise spectra (#5141)
+ Adjusted the OSEM range and brought the magnets on the center of the OSEM holders by rotating and translating the OSEMs
+ During the work we found the proper PIT and YAW gains were about -5, which are the opposite sign from what they used to be.
+ Trying to minimize the cross couplings
JD: There is still some funny business going on, like perhaps the LR magnet isn't quite in the OSEM beam. We leave the optic free swinging, and will continue to investigate in the morning.
Also, EQ gave us a better (and not pwd protected) URL for the summary pages. Please replace your previous links with this new one:
Like Steve pointed out, the summary pages show that the y-arm transmission drifts a lot when locked. The OL summary page shows that this is all due to ITMY yaw.
Could be either that they coil driver / DAC is bad or that the suspension is poorly built. We need to dig into ITMY OL trends over long term to see if this is new or now.
Also, weather station needs a reboot. And does anyone know what the MC_F calibration is?
Dead again. No outputs for the past month. We really need a cron job to check this out rather than wait for someone to look at the web page.
Max tells us that soem conf files were bad and that he did something and now some pages are being made. But the PEM and MEDM pages are bank. Also the ASC tab looks bogus to me.
The summery pages are working at a slow motion speed. It's response time 12 minutes.
Last good page May 18, 2017
Not found, error message May 19 - June 4,2017
Blank plots, June 5, 2017
40m surfs: Nicole Ing, Iswita Saikia and Sonali Mohapatra received 40m specific safety training today.
Alex Cole and Craig Cahillane received 40m specific, basic safety training last week.
Andres Medina and Andrew "Harry" Hall received 40m specific safety training. They did general safety already and their laser safety training will be this after noon.
Pooja and Keirthana received 40m specific basic safety training.
Shruti and Sandrine received 40m specific basic safety training this morning.
The 40m lab specific safety training is done. The participants were
Stephanie Erickson, Clara Bennett, Chris Zimmerman, Zach Commings, Michelle Stephen surfs and Drew Cappel postock.
They have already went through the Caltech Safety Office laser and general safety training.
They still have to read, understand and sign the the SOP for the laser & lab
ITMX and PRM moved alot. BS and ITMY just a little based on oplev reference.
Remember that the Oplevs are not good references because of the temperature sensitivity. The week long trend shows lots of 24 hour fluctuations.
A plot showing that the daily variation in the OLs is sometimes almost as much as the full scale readout (-1 to +1).
ITMX, PRM and BS watchdogs are tripped. They were restored.
Stable MC was disabled so I can use MC_REFL 1 W beam to measure green glass .
This morning, at about 12 Koji found all the front-ends down.
At 1:45pm rebooted ISCEX, ISCEY, SOSVME, SUSVME1, SUSVME2, LSC, ASC, ISCAUX
Then I burtestored ISCEX, ISCEY, ISCAUX to April 2nd, 23:07.
The front-ends are now up and running again.
I restored damping to all SUSes except ITM-east. The ITMX OSEMs are being used in the clean assembly room.
Very, very cool!
Kiwamu (or whoever is here last tonight): please run the free-swing/kick script (/opt/rtcds/caltech/c1/scripts/SUS/freeswing) before you leave, and I'll check the matrices and update the suspensions tomorrow morning.
All suspentions were restored and MC locked. PRM side osem RMS motion was high.
Atm2, Why the PRM is 2x as noisy as the SRM ?
OSEM voltages to be corrected at upcoming vent: threshold ~ 0.7-1.2V, ( at 22 out of 50 )
ITMX_UL, UR, LL, LR, SD
ETMX_UL, UR, LL, LR, SD
SRM_UL, UR, LL
MC3_UL, LR, LL