Attached are transfer functions from TMSY TFs from last night, added to the other results of last week.
I also attached a spectra of the individual osems with the suspension undamped
Installing memory in the h1broadcast0 computer, affects the dmt system.
Laser Status: SysStat is good Output power is 28.1 W (should be around 30 W) FRONTEND WATCH is Active HPO WATCH is red PMC: It has been locked 2 days, 21 hr 1 minutes (should be days/weeks) Reflected power is 1.3 Watts and PowerSum = 11.4 Watts. (Reflected Power should be <= 10% of PowerSum) FSS: It has been locked for 0 d 1 h and 21 min (should be days/weeks) Threshold on transmitted photo-detector PD = 0.54 V (should be 0.9V) ISS: The diffracted power is around 9.94 % (should be 5-15%) Last saturation event was 0 d, 11 h and 43 minutes ago (should be days/weeks)
[Corey Jeff Betsy Travis Arnaud]
Today, we had several in chamber rounds in order to improve the roll/vertical transfer functions of the TMSY suspension. Results from last thursday night attached were still showing badness, especially in the roll degree of freedom with an extra mode at 0.89Hz (first pdf), but no TF has been ran between Friday's work, and this morning. The pdf attached shows TF comparison of TMSY in April last year (orange, used as "reference"), TMSY March 11th (black, first in chamber TF, before alignment work), and TMSY last thursday, march 20th, (pink)
In chamber work from today :
1) Corey and Jeff started by moving some of the earthquake stops (quick dtt tf was ran after, cf green curve of TMSY.png). No change, since 0.89Hz still present
2) Betsy tried centering some of the flags close from the edge of their osem (cf blue curve, taken after the work). No change
3) Finally, Travis and I modified the cable routing. First we gave some slack to the cable between ISI and top mass by changing the orientation of the clamp. This significantly moved the top mass, that was probably beeing hold by those cables. Some of the osems went completely out (cf Screenshot) so we had to recenter them. We took a quick dtt TF, but it still looked somehow not good enough. We then loosened the cablings between the table and the top mass. The red curve shows how the 0.89Hz moved to 0.8Hz after the overal work.
I will run long measurements overnight, to have an idea of what's happening on the other degrees of freedom, but it sounds like their will be more cable routing work, as well as alignments to check.
Note that LLO recently had the go through the same process, cf Stuart's alog, and mitigated the issue by modifying the cables routing.
Here are some additional notes about in-chamber work today.
In-Chamber Notes:
Round 1 (Jeff & Corey)
With news of ugly peaks over the weekend from SEI TFs, Jeff & I went out to inspect the TMS for any issues (Jim locked up the ISI prior to us going in). There was nothing obvious. But Jeff did notice an internal EQ Stop being close to a wire (one from upper spring to Upper Mass); so he screwed it in a little. He then tightened all the EQ Stop screws. That was all that was done. (Jim then un-locked the ISI again)
We came back to the Control Room and were going to run some measurements, but noticed that the BOSEMs were no longer centered (!). We went out to the TMS again and centered the BOSEMs yet again (locking & unlocking the ISI as needed). We then had Arnaud run a few measurements at this point.
(as for the BOSEMs moving around....chatted with Keita, and he suspected it was due to the ISI being unlocked.)
NOTE: while inspecting the TMS, Jeff noticed the quad of magnets on some of the BOSEMs. He was surprised to see them, since other suspensions replaced them with metal blocks, per Robert Schofield's request.
Round 2 (Betsy & Corey)
Since Arnaud's measurements still showed ugly peaks at 0.88 & ~2.5Hz, Betsy & I went out yet again for inspection. She noticed Flags low for F1 & F2 (so the BOSEM Adjustment Plate was moved up). She also noticed the quad of magnets off-center for the Left BOSEM, so adjustment plate was moved forward. I re-centered BOSEMs. (ISI was locked/unlocked accordingly).
NOTE: Betsy & Arnaud said I should use the "calibrated speedometer" signals to center BOSEMs vs the BOSEM inputs, so I did this (Keita mentioned we should use the BOSEM inputs instead.
Chalking Up To Hindsight. For Future End Station Work: OK TMS Bill Of Health Immediately AFTER In-Chamber Close-Out Work
Even it takes more time, we should add the checking of the TMS & posting the ACCEPTED Free Swing spectra and/or transfer function before handing off to SEI, just to help rule out TMS if there are any questionable SEI TFs. In other words, if there are any issues with the TMS, we'll be address them faster and will be able to hand over to the SEI crew and know "for sure" TMS can't be a culprit.
...Well, I guess if when unlocking the ISI, there's the chance ISI Optics Table could have a different level compared to its locked state. (this is something Keita suggested we saw when see our BOSEMs not centered after the ISI was unlocked today).
attached are trends of the HEPI and ISI IPS & CPS positions for the past 5 days.
The unlock of the ISI on Friday is seen on the trends where there are measurable shifts. Since then the positions have been fairly stable and repeatable. The worst thing I see in this data is ~9urads tilt in the ISI Ry. This amount of motion at the CPS is in the scale of 10s of counts and is not out of our lock/unlock tolerance. Don't know if this is significant to the TMS alignment etc.
The first plot is the CPS rotations: There is a 17urad Rz, 9urad Ry & 1urad Rx. The second plot is all the HEPIs which are all insignificant.
After all the TMS work yesterday, I took a quick DTT tf this morning. No change on the SEI side. The added peak is at 2.3 hz (not a change, I just hadn't gotten around to getting a precise measurement).
NOTE: Betsy & Arnaud said I should use the "calibrated speedometer" signals to center BOSEMs vs the BOSEM inputs, so I did this (Keita mentioned we should use the BOSEM inputs instead).
Both methods are similar :
1-The BOSEM inputs can be used if trying to reach half of the open light value (corresponding to -1*the offset value).
2-The calibrated signal can be used if trying to reach 0
for the record, calibrated signal (osem output) = [(osem input - open light/2)*15000/(open light/2)]*calibration_from_cts_to_um
in other words, when osem input varies from 0 to max (cts), the uncalibrated signal varies from -15000 to 15000 (cts) and the calibrated signal from -345 to 345 (um)
The IOC had apparently stopped running. I telneted into the procServ for it on h0epics and it automatically restarted. I burtrestored it.
This morning I measured the sensing matrix for the ALS X WFS, using the oplevs:
The result for Yaw looks good:
1177countsWFSA YAW/urad ETMX yaw (61 degrees)
565counts WFS B Yaw/urad ETMX yaw (55 degrees)
-815counts WFS A YAW/urad ITMX yaw
533 counts WFS B yaw/urad ITMX yaw (39 degrees)
For pitch the two sensors are nearly degenerate:
-268 counts WFS A PIT /urad ETMX PIT
-999.6 counts WFS B PIT/urad ETMX PIT
201 counts WFS A PIT/ urad ITMX PIT
898 counts WFS B pit/urad ITMX PIT
Based on these matrixes, we would be able to close two DOFs in YAW and one pitch DOF. We know that the beam profile is really bad in PIT on WFS B (attachment to alog 10774), so we might want to try fixing this before we try lcking the second pit DOF with high bandwidth anyway. There is also cross coupling from PIT to Yaw, which might become a problem.
The measurements are saved in home/sheila.dwyer/ALS/HIFOX/WFS/
WFS_sensing_matrix_ETMX_PIT.xml ect. All measurements were made by sending a fither to PUM at 1.5Hz.
Daniel, Stefan, Sheila
Today we spent some time carefully double checking the calibration of the ALS COMM signal.
The first screenshot is a repeat of the measurement from alog 10930, locking with the additive offset and then moving the offset over resonance. The current calibration is 0.127, this is loaded in LSC_REFLBIAS_GAIN so that REFLBIAS_OUT is in units of Hz.
We moved the pole in the additive offset path from 0Hz to 1mHz to prevent the integrator from running away.
We also changed the gain on the common mode board in1 to 11dB (to avoid saturations in the additive offset path), common comp is on, in2 gain is 6dB and the REFL DC BIAS gain is 50.
in this configuration we measured the gain in the additive offset path, and got a 3Hz ugf.
We are now using the ALS-C_REFL_DC_BIAS_OUT calibrated because this is a DQ channel. This calibration has a gain of 0.g and a zero at 3Hz, the ugf of the additive offset path.
Using this measurement we get an rms of 50-200Hz depending on the time of the measurement. The variation is below 1 Hz, and seems to change with the seismic noise.
Aidan. Thomas. Dave H.
We've received the remaining parts for the CO2 laser projectors + assorted HWS parts. Currently I've unpacked 22.5 boxes out of 26.
I also added some calibrations to a selection of front-end channels. These have been safe snapped so we can burt restore them. See the attached status PDF for details.
Decoupled RGA from Y1-1 port -> Opened GV10
Pressure alarms along y1 from accumulation experiment
900 Hugh and Mitch payloading HAM5
915 Jim Correy Jeff working ETMY
919-1200 Aaron working on noise eater at EY
940 Fil making repairs t board in ISC_R2_RACK to facilitate PRC measurement
948 SUS working up test stand area for welding prep
1030 Jodi working at MY
1300 Arnaud taking tf's at EY
1317 Fire maint and HFD onsite
1345 Jeff/Andres working on SR2 at HAM5
1427 Gerardo and David O going laser hazard in H2 enclosure
Not sure how I did it, but I accidentally hit the back button on my browser while making an entry, and went back to see that the entry I was just about to post had vanished. :(
Here is the list of commissioning task for the next 7-14 days:
Green team:
Red team:
Blue team (ALS WFS):
Blue team (ISCTEY):
SEI/SUS team:
The ITMy lower ring heater had a busted edge as well as busted macor element connector. These pieces had broken during an adjustment earlier, but I suspect it was because the glass former is oversized compared to the macor element. The glass former and nichrome measured out at 0.281" while nominally the macor element that it seats in is 0.256". Trying to fit the pieces together caused the macor to start chipping and was going to obviously require a lot of force. It seemed like it would just cause the same problem all over again.
Dave O, Stefan While attempting to lock the PRC we noticed that POB_Air_B_RF_I_Err was low on signal. We traced this back to a low de-mod signal (see attached plot). We traced this down to a tripped fused in the ISC_R2_Rack. This tripped on the 17th March. We tried to reset it but it simply re-tripped again. When we locked PRX and PRY, we were also surprised that we needed to flip the feed-back sign in PRCL to lock on the carrier (compared to the settings the LSC guardian uses).
I assume by fuse you guys mean breaker right? I can't tell if this unit is now functional (as might be implied by successful locking mentioned in this post) or still problematic. I would like to understand this better in case it points to a potential flaw somewhere.
The negative regulator had the kapton insulation material under it not the gray that works. The -15 was shorting to the case. We replaced both +-15 insulating material. Unit was restored and is functional.
Unit D0902796 Serial Number S1000977 had insulation for both positive and negative regulators replaced.
We mounted the second green Faraday on a 4-axes mount and reworked the Green injection path to make the beam shape less clipped. We needed to go close to the edge of the EOM and Faraday aperture to get the best beam quality.
As for the EOM, the best beam shape was achieved when the beam is very close to the top edge of the output aperture, maybe it was already touching the hole. We backed off the height adjustment screw (closer to the output) of the EOM mount by half turns so there's no apparent clipping but it's still very close. With this backed off position the beam shape was not as good but we called it good anyway as we couldn't do anything about it.
Anyway, since the center of the aperture for Faraday as well as EOM is NOT the best position as far as the beam quality is concerned, Faraday and EOM should be on adjustable mount. The first Faraday is still fixed, and this means that the beam is not horizontal along the beam path through the first Faraday, which is OK but not ideal (e.g. the beam is not completely centered on the first lens).
We still don't know if this new beam path arrangement is any better or worse than before.
We took some beam profile measurements, which Sheila will post later. Quality of the injected beam is better, the beam coming back to WFSA looked better than before, WFSB was worse.
Our measurements from this afternoon are attached...
apperature 1 was horizontal for hese measurements, apperature 2 vertical
