kyle.ryan@LIGO.ORG - posted 15:47, Friday 10 July 2015 (19552)
IP2 changed from 5000v to 7000v earlier -> small pressure bump resulted
The temporary T240 as ground sensor for ETMX SEI sensor correction was swapped on Tuesday 7 July with an STS2. Attached are spectra comparing the signals. Obviously we can't compare signals at the same time so the T240 time is 3 July at 0200 local and the STS2 time is 9 July at 0200. Based on the wind trends, these are pretty quiet times for wind.
To assess the stationarity of the Spectra, I walked before and after this time a few hours on July 3 and the variability below a Hz can be many factors. With the 0200 July 3 signals as reference, I walked before and after 0200 on 9 July and really found no close match, again especially at lower frequencies. The Z DOF of the T240 below about 30mHz seems to be main outlier but above about 200 mHz the traces are maybe within a factor mostly. There is an exception to that centered around 0.6Hz with the T240 showing a bit higher amplitude especially on the Y DOF. Maybe we could argue that our calibrations for these two instruments are correct.
Leonid.Prokhorov, Jeffrey.Kissel We continue the charge measurements on ETMs. The data are beginning to be consistent with a small increase in charge, consistently negative. For the past few weeks since the discharging the charge has been small (<10 [V] Effective Bias Voltage), and roughly consistent with a parent Gaussian distribution with a mean about 0.0 [V] Effective Bias Voltage. However, as we get more data, we're beginning to see a case for a slow negative charging of the test masses (about 2-5 V/week) in at least half the quadrants (ETMX UR, UL, and LR; ETMY (the pitch estimates of) UR, UL, and LR). The uncertainty of these measurements is too large to state that the trend is statistically significant, but yellow flags have gone up. This argues that we should continue roughly daily (say, thrice a week) measurements of the charge, and we need to continue to do so for another week or three. There are three sets of plots, each which show the same data in a different way: (1) ETMX.png & ETMY.png show the "raw" data, where the result of each estimate of the effective bias voltage shown *since* the discharging. Each single data point is an estimate of the effective bias voltage, i.e. the charge, as determined by driving the test mass while varying the requested bias voltage and measuring the response with the optic's optical lever. (2) ETMX_Mean.png & ETMY_Mean.png shows both the mean and standard deviation, and weighted mean and sqrt(weighted variance) of the charge measurements for a given day (which can be from ~4 to ~15 of these 12 minute measurements per mean point). We believe this better shows the long-term trend of the charge. (3) ETMX2015.png & ETMY_2015.png shows the mean charging measurement results since January 2015, i.e. it includes data when the test masses were charged and shows the discharge which happened in Mid-June.
It is useful to note that if the bias is going in a negative direction, the charge on the test mass is going positive. This would be consistent with uv or xuv photoemission from the front surface of the test mass. Refer to DCC T1400647-v1. The slow growth of charge on the LLO etmy is also going in the same direction toward positive charge.
I modified some scripts to make easier processing of the charge measurements. 1. Couple of matlab scripts allow to analyze several sets of measured results (instead analyzing one point at time). You can input the set in ESD_Analyse_ManyMeasurements.m, it calls ESD_analysis.m which is a little bit adapted version of ESD_UL_LL_UR_LR_analysis_07_H1.m . As a result you have the set of .mat files in corresponding folders and one figure per set showing dependence of response with different bias voltage. You can processing ETMX and ETMY all together. You can process all data of the day in one script. 2. I modified the long trend matlab script to make two new kinds of plots (you can see it in alog https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=19458). Also, it create plots for several TMs, if you need. New version is Long_Trend_H1_v2.m . 3. I want to modify python script, but it seems that I can do only one improvement, when I want two and have else one trouble. - First, which seems to be done, is making several measurements in line, without pause or waiting for operator's reaction. ESD_UL_LL_UR_LR_charge_07-H1-ETMY_Long.py repeats the measurements as long as "ENTER" is not pressed. After this it finish round of the measurement and stops. For sure, it can be stopped by ctrl+c (and you'll have partly measured directory). - Second - we often have time on both ETMs together. I'd prefer to have one script which measure charge at both arms at the same time. Not in line, as it is realized now, but simultaneously. Now I use two scripts (one for each arm, but I'm not sure if it's the best choice). - Third, at first run scripts return an error. It happens not at start, but in several first minutes of work. Seems that it happens once for each terminal. These errors do not stop the script. Also, I saw that length of "waiting for response loop" (I mean, number of measured GPS seconds) may differs. It happens rare, but it happens. The measurement time usually becomes smaller, but once I saw more than 2 minutes of measurement for one loop (instead 30 seconds). For sure, any of these errors kills all the processing for the data set. So, if you want to use modified versions of scripts - you are welcome! If you have any suggestions or critic - you are welcome! If someone could improve python script - I would be happy! Links for all the committed files: https://redoubt.ligo-wa.caltech.edu/svn/sus/trunk/QUAD/Common/Scripts/ESD_analysis.m https://redoubt.ligo-wa.caltech.edu/svn/sus/trunk/QUAD/Common/Scripts/ESD_Analyse_ManyMeasurements.m https://redoubt.ligo-wa.caltech.edu/svn/sus/trunk/QUAD/Common/Scripts/Long_Trend_H1_v2.m https://redoubt.ligo-wa.caltech.edu/svn/sus/trunk/QUAD/Common/Scripts/ESD_UL_LL_UR_LR_charge_07-H1-ETMY_Long.py https://redoubt.ligo-wa.caltech.edu/svn/sus/trunk/QUAD/Common/Scripts/ESD_UL_LL_UR_LR_charge_07-H1-ETMX_Long.py
(times in PST)
0803 - Robert to the LVEA to get a few things
0825 - Robert out
0855 - Katie to LVEA to level magnetometer
0920 - Richard to roof
0927 - Katie out
I came in early to get some work done and decided to try to lock before I began. I very easily made it up to Bounce roll damping before it lost lock. I didnt see any modes badly rung up, but many suspensions were saturating according to VerbalAlarms.
Another look at the sensors after moving units around on Tuesday. See attached for spectra from a quiet time around 3am local. Robert sees things looking pretty good except for the drop in coherence on the Z dof between the ITMY and the HAM5 units. This may be the 30 meters between those instruments but we don't see the coherence drop on the other DOFs.
I've recentered the Masses again on the ITMY unit to see if that helps. The other differences seen mostly on the STS2 at the ETMX position are reasonable given the distances to the other sensors.
Last night I tried running the corner station BSC's in with some blends provided by RichM. The end stations stayed in the old configuration. Attached plots show the performance of ITMX vs ETMX. I compare RX/Y on ETMX and RY/X on ITMX. The results are mixed. Dashed lines are ITMX, solid lines are ETMX.
Something else to note, ITMX was not performing as well as the other chambers (something like an order of magnitude worse at a few hz, no different at low frequency though), the new blends now bring it's performance up to the other chambers. I've looked at the blends and all other controls components on this chamber, and haven't been able to find a reason for the difference. Suspicious. Last plot shows the difference, red and blue are the new blends, green and brown(?) are from the previous night with the "old" blends.
Killed the digital video camera software running on h1digivideo1, then killed several processes that wouldn't die nicely, then restarted the digital video camera software. The EPICS IOC was not running properly for camera 18, this restart seems to have fixed it.
New Ref signal = -2.03V
Vac
SEI
SUS
CDS
Fac
Comm
Weekend Work: Elli and Nutsinee will be coming in to do HWS work
Work safe and have a great weekend!
Sheila, Stefan, Elli, Nic
This afternoon we got a little more time with the IFO. We redid inital alingment and were able to engage the ASC which increased our recycling gain. We were able to power up to 15 Watts without a problem, when we increased the power to 23 Watts a 0.4 Hz oscillation that showed up mostly in SRC1 PIT and SRC2 PIT knocked us out of lock. We've had difficulty in the early part of the evening with ALS, we have the glitches that show up in the arms even when only the arms are locked, reminding us of the glitches seen in alogs 17576 and 15242. As before, these glitches went away a couple of hours and we are now locking OK again.
We have reduced the time for the REFL trans ramp from 5 seconds to 1 second, this seems to be fine and we could think about making it shorter or reducing other ramp times in the final stages of CARM offset reduction. We haven't had the REFL trans lockloss today, but this problem has always been intermittent so we will have to continue locking for several days to see if speeding it up actually helped.
Screen shots of several of these ALS locklosses that seemed to go away after a few hours.
We've had a similar problem this morning. We saw one glitch at around 18:11:24 UTC, at this time we were sitting with only the arms locked and tidal from the green PDH to the ETMs.
Now the problem has gone away on its own again.
On June 29, 2015, LHO received a forwarded email from Hanford site personnel which contained this comment: "Beginning Monday, July 6, there will be an increase in truck traffic . . . near the 300 Area. Waste material will be shipped to the Environmental Restoration Disposal Facility in central Hanford. The remediation effort will continue until the spring of 2016 . . . truck traffic will be present between the hours of 7 a.m. and 3:30 p.m." The truck traffic mentioned here is the familiar ~30-ton loads in orange containers riding on transport trucks from the Hanford 300 area (~12 miles SE of LHO) to the ERDF pit (~10 miles W of LHO). One of our site contacts indicates that we can expect about 120 loads per day to ERDF (meaning 2x round trips, but the reverse trip is with an empty container). At present the hauling contractor anticipates that the loads will move only on the day shift, but these plans could change. Current daytime PEM-SEIS 1-3Hz plots show this additional traffic.
1010 hrs. local -> Spun down Y-end turbo and scroll pumps 1040 hrs. local -> Started pump cart at Y-end RGA and energized RGA filament 1105 hrs. local -> Spun down X-end turbo and scroll pumps 1530 hrs. local -> started scan of Y-end 1545 hrs. local -> Valved-out Y-end NEG 1600 hrs. local -> Valved-in Y-end NEG 1615 hrs. local -> Stopped Y-end RGA scan 16?? hrs. local -> De-energized Y-end turbo levitation 1655 hrs. local -> De-energized X-end turbo levitation
0829 - Elli to LVEA to turn on Illuminators
0848 - Elli out
0939 - Buba to Mids for fan work
0956 - Kyle to EY to turn on pumop cart
1129 - Bubba back
1144 - Nick to LVEA ISCT1
1145 - Hugh to LVEA to unlock HAM6 HEPI
1146 - Elli, Mike, and students to LVEA for quick tour
1151 - Leo starting charge measurements
1200 - Mike and students out
1210 - Hugh out
1214 - Elli out
1320 - Gerardo to EX to retrieve vac equipment then to MY
1350 - Fil to EX getting length for the new cables to be installed
1509 - Gerardo back
1516 - Kyle to EY for RGA scan
The current of the REFLAIR diode while in lock is about a factor of 10 below where shot noise is equivalent to dark noise.
In order to better understand the out-of loop behavior of the Common Mode loop, I did a lightbulb test on the REFLAIR_A diode. The thermal radiation from the lightbulb acts like a quantum limited light source at 9MHz.
The light was powered by a benchtop DC power supply. I mounted the bulb right in front of the diode and varied the DC light level (as seen by the REFLAIR_LF channel) and recorded the noise floor in the REFLAIR 9MHz demodulated channels. The whitening gain was temporarily changed from 12dB to 42dB for this test to overcome the ADC noise level.
The attached pdf file shows the noise vs current curve, and a fit. EDIT: apparently the LF channel is already calibrated in milliWatts. The 9MHz channel is not calibrated to physical units (though the calibration could be determined from the shot noise). As one can see, the light level we use in lock is about 10 times smaller than where shot noise starts to overcome dark noise.
REFLAIR also has an ND filter stack screwed directly on the diode box. Since we have so little light, maybe we should remove it.
data files
The amount of rf coming out of REFL9 in full lock (at 20+ W) is about −10 dBm, or 70 mV. It should be fine to switch over.
Attached is a noise budget for the DARM spectrum from 2015-06-07 00:00:00Z–02:00:00Z. Notes:
Conclusions:
Attached are the MICH and SRCL coupling TFs into OMC-DCPD_SUM.
