jeffrey.bartlett@LIGO.ORG - posted 13:27, Thursday 20 March 2014 (10897)
Payload HAM5
10:45 to 12:00 Hugh and Apollo using fork lift to add payload to HAM5.
10:45 to 12:00 Hugh and Apollo using fork lift to add payload to HAM5.
No channel value changes are being recorded for the duration of the backup.
model restarts logged for Wed 19/Mar/2014
2014_03_19 15:43 h1iopsusquadtst
2014_03_19 15:52 h1iopsusquadtst
2014_03_19 18:02 h1susetmx
all restarts expected.
Dave O I re-analyzed the data that was used to determine the PRC Length (see alog 9th March, 2014) to see whether it was possilbe to determine the losses in the PRC and hence the Schnupp Asymmetry. The results hint at the Schnupp Asymmetry being around 9.5 cm (See attached report). However the measurement will need to be re-done with the increased signal to noise that was obtained late last week to be certain.
A make install has been performed for h1sustmsy, h1iopsusauxh2, h1ascimc, and h1sustmsx to restore medm directories in /opt/rtcds/lho/h1/medm. These were not restored on Tuesday but should have been. They are not new missing directories. I verified this against the build log and the list of missing files to see they had not been restored with the other missing files.
Laser Status: Output Power : 28.3w FRONTEND WATCH is green HPO WATCH is red PMC: Locked for : 1d 18h 16m Reflected power : 1.2w Power Sum : 11.3w FSS: Locked for : 0d 0h 55m ISS: Diffracted power : 13.105% Last Saturation Event : 1d 18h 30m
WP 4517 The h1oaf0 computer was shut down to allow addition of a 5th ADC card for use by h1peml0. The h1iopoaf0 model was modified to add ADC4. Card assignments to the models will be ADC0, ADC1, ADC4 to be used for h1peml0, and ADC2, ADC3 will be used for h1tcscs. This allows the same ADC card assignments to be used at LHO and LLO for the tcscs model. A burtrb was done on h1tcscs before shutdown, it can be found in target/h1tcscs/h1tcscsepics/burt/h1tcscs_burt_140320_100830.snap The h1peml0 model was modified to move ADC2 to card_num=4.
07:30 to 08:15 Apollo craned the two HAM5 Doors in the LVEA
~0900 -> Increased from ~5 psi to ~15 psi -> no change in slope of Y1 accumulation ~1045 -> Increased from ~15 psi to ~25 psi -> no change in slope of Y1 accumulation (historically GV6 won't "cam over" or hard-close until much higher closing pressures are applied. We would like to ensure that its gate is fully contacting its O-rings so as to eliminate hydrogen pumping from the adjacent vacuum volume for a, at least, a portion of our Y1 accumulation data collecting)
(Corey, Jax, Keita)
GREEN Beam Alignment & Power Measurements
Continued with alignment work from yesterday. So, yesterday we had the green beam coming form the table into the chamber, centered on the QPDS, retroreflecting off the ETM, and heading back toward the table, but hitting the bottom periscope mirror under the TMS table. So, first thing we did was pitch the TMS "up" (slid pitch masses back). We adjusted a few BOSEMs after this pitch move. Once we had pitch good, we roughly made it back out of the chamber through the viewport...but to do this we had to steer the TMS in yaw. So we were off a little in yaw, but able to get back outside on the table with yaw bias. But because we didn't want to use up all of our range, we were going to have to PUSH the entire TMS Assembly...we broke for lunch at this point to find out where the tools were.
Oh, should mention that we measured the green power as it (1) enters the TMS, and then the (2) reflected & (3) transmitted light of the BS which sends light to the Green QPD Sled....unfortunately, I wrote these values on the cds laptop. So will post powers later.
Push In Yaw (& more Pitch) & Dropped Bolt
Set up to yaw the entire assembly counterclockwise (as seen from above the BSC chamber)...or basically a Right Handed Turn. Now, the real estate is pretty tight upstairs. while trying to install a teflon-tipped dog clamp on the rear-end of the TMS, I dropped a 3/8" bolt. Luckily it didn't hit anything on the TMS, but I believe it went down underneath the temporary flooring. Continue with setting up the pushers. Once we were ready, we had the green beam & a damped TMS. I then pushed the assy in yaw while Keita watched the beam. This worked out well, and we fixed yaw. I believed another BOSEM adjustment was made here...perhaps we did another pitch adjustment here (we did a few of them through the day).
BS for Hartman Path Missing
Realized we were missing an optic on the in-air table (BS to pick off for the Hartman path). Aiden says this optic is on its way. Anyway, we'll have to install that later (it'll change alignment, but we'll use irises to maintain alignment).
IR Path Work Begins: Pointing Out IR Viewport & Beam Diverter Work
The green beam is also used to align the IR path. We steered out this beam by steering the "entry" mirror for the IR path on the TMS table. After this was done, Keita looked at the path for the Beam Diverter and steered the beam to the High Power Beam Dump.
Next: IR Path to QPDs
Tomorrow, we'll continue with IR path (via green beam), and get the beam onto the IR QPD sled ("this is the trickiest job" says Keita....he says if it goes well, we might be able to finish this job Thurs, but it may carry over to Fri. We shall see.)
(whoops...looks like Keita and I were thinking the same and like to make late night alogs). Sorry for the redundancy.
Round Of Rubbing Prevention (forgot to mention for Wednesday's work)
Keita inspected/backed off EQ Stops for the TMS Upper Mass to help reduce the chance of rubbing due to them.
He also adjusted the clamping of the bunch of cables between the top of the Upper Mass to the BSC Optics Table (this run previously was fairly tight).
When we aligned TMSY to the ETMY such that the green beam retro-reflects from the ETMY, we needed to put about 400urad YAW offset in TMS suspension bias.
TMSY slider can take 600urad so there's still 200urad head room, but that's too thin a margin as it could be easily eaten by yet unknown ETMY YAW offset.
We used pusher setup to move the TMSY cage as we watched the beam motion. Fixing the dog clamps and removing the pusher moved the TMS back a bit, but we ended up with a perfect alignment with 40urad YAW offset, which is really good. We also adjusted the PIT balance by moving big slide masses under the TMS ISC table, and a small screw used as a weight on the TMS ISC table.
We aligned the IR transmission path that goes to ISCTEY by using the green beam leaking into IR path. We also adjusted the high power beam dump path. During this procedure we found that moving steering mirrors change the balance, and adjusted the slide masses again.
We will look at the IR QPD path tomorrow.
Jeff, Arnaud, Sheila
This afternoon the arm cavity was staying locked for minutes at a time, not really long enough to make a useful progress on WFS.
We decided to work on OpLev damping, in the hopes that we would be able to stay locked longer with OpLevs.
First we noticed that in the locally modified quad models for ETMX and ITMX, the OpLev damping signal was summed into the drive to the PUM after the drive align matrix, meaning that we would not be able to take advantage of all Keita and Arnaud's work of diagonalizing the PUM drive. So we made a change to the front end model to sum the oplev damping signals in before drivealign, but after the lock out switch. For the record this means that there can be a signal going to the osems even when the lock outout switch is off. Screenshot attached of the new version of the model, which is committed to the svn. This hasn't yet been done for L1 or ITMX, but we will want to do it if we are going to use OpLev damping permanently.
Based on Keita's measurement in alog 10747 we designed a controller to have a lower ugf of 0.1Hz and an upper ugf of 2.5Hz, with a pole at 10 Hz, which is now loaded in FM4 of H1SUS-ETMX_L2_OLDAMP_P. This immediately saturated the DAC, and we had to turn the gain down to -0.1 to prevent constant saturation. The current loop gain is attached, with gain from 0.4-0.65 Hz and gain margins around 40 degrees. If we want to use more gain, we will need to drive the UIM which means we will need to diagonalize it.
Since we are planning to use PUM for WFS as well, we will probably run into the same saturation problem with WFS, another reason to diagonalize the UIM.
We measured the RMS three times, before we started with no damping off (green) 85.5nrad then with damping on (magenta) 29.5nrad, and again with damping off (red) 48.2nrad. Because the ground motion was changing as we made he measurements, it is not totaly clear from the spetra that the loop is helping. The ratio between the ISI tilt (RY) and the OpLev spectrum at 0.43 Hz is decreases by ~5dB as we would expect from the loop gain.
Is it railing due to high frequency component?
You should look at the ASD and RMS of the coil output with damping on and off. See also the alog of Jeff.
I had a look at Yaw, where the situation seems better than in Pitch. The plant for Yaw is verry similar to PItch ( see Keita's alog linked above), however most of the yaw rms comes from low frequenies, mostly from a peak around 0.13Hz. So this loop has a lower lower UGF, one at 0.03Hz with around 75degrees phase margin and the upper ugf is just above 1 Hz with 130 degrees phase margin. The controler has a zero at zero, a pole at 0.1Hz and a notch at 0.6Hz. (See attached open loop TF)
After looking at the spectrum with the loop on, I decided to add a resonant gain at 0.13 Hz, shown in open loop design in the attached foton screen shot. The filter Plant is an imitation of the Yaw to yaw transfer function in Keita's alog.
The last attached screen shot are spectra with and without damping. With the damping and resonant gain on the ASD is reduced by a factor of 10 at 0.13Hz, and the rms is reduced by a factor of 2 compared to no damping.
The Yaw damping doesn't saturate the DAC, so I think this is good and we can run with this on. Pitch will need more work, as Keita says.
Has the analog whitening settings changed on the ETMX optical lever? I've compared a high-frequency spectrum with a measurement I took in February, and there's reported tons more motion above 2 [Hz], when the ISI motion is roughly equivalent if not better at these frequencies (see attached). Looks there's an extra 1:10 analog filter that's not being compensated or something...
Looking at a previous OPLEV spectra that was made in February on ETMX ITMX and ITMY (calibrated in urad/sqrtHz), it looks like the signal amplitude @ 10Hz (on the three of them) was similar to what you have on your red curve (~0.1 nrad/sqrtHz). Maybe the green trace (reference) was taken with a digital compensation filter engaged, but no analog whitenning ?
Refer to ALOG-10267 for the changes in whitening settings on Feb 21st 2014. This accounts for the two orders of magnitude difference you see above 10 Hz.
Aidan, Thomas, Dave H.
We spent most of today hooking up cables in the mechanical room. Both chillers now have DAC control (although the output channels are still to be configured). We installed most of the TCS cables in the CER too. A few of the long cables (cables X&Y: 46 and 47) are in back to front: we need to pull them out and install them flipped around (we're not going to use gender changers as we'd need too many of them).
Status is current in the attached PDF.
160 channels added and 4 removed for a current total of 122,626.
Updated again to remove H1:IMC-VCO_CONTROLS_EXTFREQUENCYOFFSET.
(Alexa, Sheila, Kiwamu) -- a post from yesterday that didn't get uploaded due to alog maintenance
I repeated the IMC intensity noise measurement that was done for HIFOY (alog 7364):
Step 1: Measure the power spectrum of MC RIN via H1:PSL-ISS_PDA/B_CALI_DC_OUT with both the ISS off (REF 7) and on (REF 11) (see 20140318_MCRIN_Data png for these measurements).
Step 2: Calibrate via the following:
IMC_trans_freq_noise = f0/L*PWR*(2+1+1)/c/mMC2/(2*pi*f)^2 * RIN where f0=2.818e14 Hz (red frequency) L=16.4736 m (IMC length, one way) PWR=1.36e3 Watt (Power in the IMC, = 8290 mWatt * Finesse/pi, Finesse=516) mMC2=2.9kg (Mass of MC2 mirror, same as for MC1 and MC2) (2+1+1) (effect of MC2 at 0deg, MC1 at 45deg, MC3 at 45deg) f (Audio frequency)
This calibration is set up in matlab file: calib.m (and returns the HZ txt file). We only use PDB_DC_CALIB since this measurement gives the out of loop sensor noise (meanwhile PDA gives the in-loop). See screenshot for result.
Note: In order to ensure a proper calibration of these channels with the increased power into the MC, I adjusted H1:PSL-ISS_PDA/B_CALI_DC_GAIN such that the tsdavg was 1. PSL TEAM: does this change the gain of the loop?? Feel free to return to the nominal values. The ISS and MC still lock under the new configuration.
(all these files can be found in: /ligo/home/alexan.staley/Public/IMC_IntensityNoise/... I was not able to upload them because the files were too large)
The next step will be to insert this result into the model...TBD
I attached the wrong DTT snap shot. I calibrated PDB (not PDA); however, the DTT snapshot I previously posted was of PDA. I have attached a matlab plot of the dtt power spectrum of PDB.
