Displaying reports 64061-64080 of 83122.Go to page Start 3200 3201 3202 3203 3204 3205 3206 3207 3208 End
Reports until 13:20, Saturday 11 July 2015
H1 TCS
eleanor.king@LIGO.ORG - posted 13:20, Saturday 11 July 2015 - last comment - 18:02, Saturday 11 July 2015(19568)
Hws alignment ITMY

Nutsinee, Elli

When we arrived the IMC was not locking so we changed some settings to get it to lock.  Changed PSL differacted power to 7% up from 3% by changing H1:PSL-ISS_REFSIGNAL to -1.96V.PSL.  The PSL power was 1W when 2W  was requested at the rotation stage.  So we searched for home, and now requested power matches again.

We tried to lock the arms in green without success.  The X-arm PLL was not locked, we changed Crystal frequency to 100MHz and now it is locking, however the ALS_XARM and Y_ARM guardian still report faults "PLL; PHD", and "Ref. Cav. Power", which we couldn't fix.  We noticed the reference cavitytTPD has dropped from 0.85 to 0.7 V in the last 24 hours (see plot.)

We aligned the corner station optics using the oplev trend to where they were last night in order to do the HWS alignment.  We noticed BS oplev Yaw is showing zero as output.  Without the green from the arms this alignment was difficult.  in any case, we are starting to think that this HWSY alignment is proving too difficult with the current (wrong) in-vacuum lens installed-  the beam return beam is the same size as the mirrors we are using, and we have never been able to get rid of clipping patterns on the beam.

Images attached to this report
Comments related to this report
evan.hall@LIGO.ORG - 18:02, Saturday 11 July 2015 (19571)PSL

The refcav normalized transmission threshold for the end-station PLLs was changed from 0.4 to 0.3 in order to allow the PLLs to lock.

If there is an incursion into the PSL next maintenance day, it might be good to touch up the refcav pointing.

H1 INS (ISC)
stefan.ballmer@LIGO.ORG - posted 00:08, Saturday 11 July 2015 (19565)
ASC stability work at 24W
Nic, Sheila, Evan, Stefan

- Turned on ITMX PIT oplev (ITMY PIT OPLEV was already on)
- DC coupled SRM PIT oplev turned on.
- Tried new SRCL input matrix YAW:
   AS 36    AI    AQ     BI    BQ         
   OLD:   -0.6   0.3    0.3   0
   NEW:    0     1.0    0     0
- This seemed better at higher power for RF offsets, but is too early for judgement.
- Also tried new SRCL input matrix PIT:
   AS 36    AI    AQ     BI    BQ         
   OLD:    0     0      2     0
   NEW:   -0.5  -0.5    0     0
- We didn't keep this one though because it seemed worse at low power.

- Attempts later tonight were hampered by winds up to 30MpH in the corner.
H1 CDS
sheila.dwyer@LIGO.ORG - posted 22:07, Friday 10 July 2015 - last comment - 18:32, Sunday 12 July 2015(19566)
EPICs freezing

We've noticed two more examples of epics channels freezing for a few seconds.  Yesterday (July 9 16:25:09 UTC) and tonight (0:22:49 UTC July 11)

Comments related to this report
david.barker@LIGO.ORG - 08:07, Saturday 11 July 2015 (19567)

I have opened an FRS on this issue (#3279) which contains details of my investigation. I have seen two extended CA freeze-ups of LSC over the past two days (11 and 14 seconds in duration) with an apparent increase in CPU load on h1lsc0 at the time. The DAQ data does not show any drop-out, this only impacts CA access to LSC data. This is an inconvenience for MEDM and StripTool, but has potentially more serious implications for Guardian. Investigation is continuing. With only one large event per day it unfortunately takes some time to gather data. I'm also trying to reproduce the issue on the DTS.

https://services.ligo-la.caltech.edu/FRS/show_bug.cgi?id=3279

evan.hall@LIGO.ORG - 18:32, Sunday 12 July 2015 (19569)

Just to build statistics, we observed these dropouts as well:

  • 2015-07-11 00:21:40 Z
  • 2015-07-13 01:31:20 Z
H1 AOS (ISC, SYS)
sheila.dwyer@LIGO.ORG - posted 21:36, Friday 10 July 2015 - last comment - 21:09, Monday 13 July 2015(19562)
OMC fringe wrapping

Nic, Sheila

We put an excitation into the HAM6 ISI ISO Y filter bank, (30000 counts at 0.3 Hz) from about 3:17-3:19 UTC July 11.  We then did a by eye fit  (on a log log scale)for a fringe wrapping model.  We expected the excitation to result in 30 um motion of the OMC, but we had to use 36 um to get the fringe speed right. We get an amplitude reflectivity of 1.6e-7 for the single pass shelf. (compare to 1e-5 measured in 17919)  We see no evidence of a second shelf or a shelf in the null stream.  

We plan to make measurements in exactly the same was as 17919, if we get a chance again tonight.

Images attached to this report
Non-image files attached to this report
Comments related to this report
sheila.dwyer@LIGO.ORG - 21:09, Monday 13 July 2015 (19609)

There is a typo in this alog, the reflectivity is r=160e-7, as the legend in the plot says, not 1.6e-7 as I wrote.  

H1 SUS (ISC)
nicolas.smith@LIGO.ORG - posted 18:19, Friday 10 July 2015 (19561)
Settings for ETMX roll mode damping

(stefan sheila evan nic)

We had to modify the mode damping settings to get the ETMX roll to decay. These might not be stationary, but here is the record of the settings that worked.

damping settings

Images attached to this report
H1 ISC (SEI)
sheila.dwyer@LIGO.ORG - posted 18:06, Friday 10 July 2015 (19560)
High wind DRMI

Sheila, Stefan, Evan, Nic

Today we've had winds around 25 mph most of the day, now the gusts are approaching 40mph.  The attached screenshot shows a failed DRMI acquisition right before a successful one.  In the top panel, the limits are set to the DAC saturation.  In the failed attempt we saturated PRM M3 after 4 seconds, in the successfully lock we don't engage the offload to M2 until 16 seconds after the lock is acquired. 

A screenshot of the guardian log during the successfully lock is attached, we engage the WFS centering before offload.  I've rearranged the guardian to engage the offload before engaging the centering and also speed up the engaging.  It now takes about 2.5 seconds from locking to engaging the offload.  

 

Images attached to this report
Non-image files attached to this report
H1 ISC (SUS)
evan.hall@LIGO.ORG - posted 17:18, Friday 10 July 2015 - last comment - 17:16, Monday 13 July 2015(19559)
EY ESD strength change

Stefan, Sheila, Nic, Evan

We remeasured the relative strength of the EX and EY ESDs in full lock. EX was driven with the high-range driver (40 V/V dc), and EY was driven with the low-noise driver (2 V/V dc). All other things being equal, we expect a relative strength of 20 V/V between the two actuation chains.

We found that the relative strength is instead 30 V/V (see attachment, which includes a digital gain of 30 ct/ct in the EY path). When we first did this measurement (back in May, pre-discharging), the relative strength was more like 50 V/V. So we are closer to the nominal value.

We successfully transitioned control of DARM from EX to EY with this new digital gain. We also took a quick DARM OLTF, both before an after the transition. The attachment shows an old, pre-vent OLTF (blue), today's OLTF with EX (green), and today's OLTF with EY (red).

Images attached to this report
Comments related to this report
rich.abbott@LIGO.ORG - 17:16, Monday 13 July 2015 (19604)ISC
A relatively small point, but the LV ESD Driver DC gain is actually closer to 1.9 V/V at low frequencies.  There's a pole just above 150Hz.
LHO VE
bubba.gateley@LIGO.ORG - posted 16:48, Friday 10 July 2015 (19558)
Beam Tube Washing
Scott L. Ed P. Rodney H.

7/8/15
Cleaned 68 meters of tube, bellows, and crevices ending at HSW-2-093. Test results posted below.
Removed lights and started relocating equipment to next section and hanging lights.

7/9/15
Cleaned 79.6 meters of tube and ending at HSW-2-089. Bellows and crevices still need to be cleaned.

7/10/15
The bellows and crevices on the previous section were cleaned and tested. Results posted below.
The lights were removed and relocated to the next section. The crew started vacuuming the support tubes and capping them.   21 meters of tube cleaned.

 A total of 227.6 meters of Y-Arm tube has been cleaned.

 
Non-image files attached to this report
LHO FMCS
bubba.gateley@LIGO.ORG - posted 16:14, Friday 10 July 2015 (19554)
Beam Tube Enclosure Joint Repair on the X-Arm
Chris S. Joe D.

7/8/15
Installed aluminum strips on 39 joints beginning 604 meters from the corner station and continuing north and caulked 13 of those.

7/9/15
Finished caulking the joints from yesterday and cleaned 10 additional joints ending 756 meters north of the corner station. 
H1 PSL (PSL)
cheryl.vorvick@LIGO.ORG - posted 16:14, Friday 10 July 2015 (19555)
PSL FSS TPD has fallen below 0.9V

plot 1: PSL FSS TPD (top), PMC TRANS (bottom) - 7 days of data - channels changed behavior about 4 days ago, and TPD fell below 0.9 sometime in the last day or so.

plot 2: PMC REFL (top), PMC TRANS (bottom) - 7 days of data - PMC REFL climbing faster in last 24 hours or so.

plot 3: Ch7: PSL OSC BOXHUM (upper right) seems to be correlated with other three channels in the first 1/2 of the plot.

Images attached to this report
H1 General
cheryl.vorvick@LIGO.ORG - posted 16:05, Friday 10 July 2015 (19553)
Ops Day Shift Summary:

- IFO in commissioner's hands most of the afternoon

- during lunch, IFO locked at 10W, and I raised to 15W about 30 minutes later, it held about 15 minutes, then LL

- minimal activities, no LVEA entry

Current:

- locked, commissioning going on

- PSL FSS TPD flashing yellow, since it's below 0.9V - see plots in alog

- RobertS and DickG and Nutsinee and Elli all have weekend work permits, #5343, #5344, and #5342, respectively

LHO VE
kyle.ryan@LIGO.ORG - posted 15:47, Friday 10 July 2015 (19552)
IP2 changed from 5000v to 7000v earlier -> small pressure bump resulted


			
			
H1 SEI
hugh.radkins@LIGO.ORG - posted 15:35, Friday 10 July 2015 (19551)
Compare ETMX Ground Sensor T240 vs STS2

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.

Images attached to this report
H1 SUS (CAL, DetChar, ISC, SUS, SYS, VE)
leonid.prokhorov@LIGO.ORG - posted 13:11, Friday 10 July 2015 - last comment - 20:58, Friday 10 July 2015(19547)
OPLEV charge measurements; Data are beginning to be consistent with a small increase in charge, consistently negative
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.
Images attached to this report
Comments related to this report
rainer.weiss@LIGO.ORG - 20:58, Friday 10 July 2015 (19564)SUS, VE
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.
H1 ISC
nicolas.smith@LIGO.ORG - posted 15:19, Thursday 09 July 2015 - last comment - 14:33, Friday 10 July 2015(19531)
Sensing noise on REFLAIR 9MHz

Summary

The current of the REFLAIR diode while in lock is about a factor of 10 below where shot noise is equivalent to dark noise.

Details

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.

lightbulb

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.

Images attached to this report
Non-image files attached to this report
Comments related to this report
nicolas.smith@LIGO.ORG - 15:28, Thursday 09 July 2015 (19533)

data files

Non-image files attached to this comment
evan.hall@LIGO.ORG - 14:33, Friday 10 July 2015 (19549)

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.

Images attached to this comment
LHO VE
john.worden@LIGO.ORG - posted 14:37, Wednesday 08 July 2015 - last comment - 16:28, Friday 10 July 2015(19501)
NEG Pump at END X

END X has been transitioned to the NEG pump. The main turbo is isolated but still spinning.

Pressure has remained at ~2.2e-8 torr.

Comments related to this report
gerardo.moreno@LIGO.ORG - 16:28, Friday 10 July 2015 (19557)

Installed Pump

Images attached to this comment
LHO VE
john.worden@LIGO.ORG - posted 15:03, Tuesday 07 July 2015 - last comment - 16:19, Friday 10 July 2015(19471)
NEG Pump at END Y

Kyle, Gerardo, John

 

The NEG pump has been valved into the END Y volume and all appears well.

The plot shows 2 hours of the BSC chamber pressure. Initially the main turbo was pumping the station along with the LN2 pump and open to the tube. The LN2 pump had been opened to the BSC earlier in the day and we let the pressure settle over lunch.

With the turbo still connected you can see the pressure fall as we open the NEG to the volume. Next the turbo was valved out and the pressure returns to near the starting value.

 

So far so good!

Images attached to this report
Comments related to this report
gerardo.moreno@LIGO.ORG - 16:19, Friday 10 July 2015 (19556)

Installed pump.

Images attached to this comment
H1 ISC
nicolas.smith@LIGO.ORG - posted 16:38, Thursday 02 July 2015 - last comment - 20:22, Friday 10 July 2015(19432)
Couldn't make fringe wrapping with bright michelson

(evan jenne nic)

We wanted to investigate the OMC alignment/backscatter problem. Driving the OMC SUS in Yaw has been known to cause backscatter noise due to the modulation of the optical path length when the OMC moves in Yaw.

Our procedure was to lock the vertex optics in a bright michelson configuration (a state has been added to the IFO_ALIGN guardian to make this easy). Then we wanted to drive the OMC in yaw and choose the yaw->longitudinal matrix element such that the center of rotation would be about the input beam, rather than the omc center of mass. This would be determined by minimizing the scatter as measured by either OMC trans, or the MICH error point.

I was surprised that we were not able to induce any significant backscatter fringe wrapping noise in this configuration. We drove the OMC SUS in longitude up to the point that the beam was misaligning enough to noticibly affect the OMC DC trans.

We also drove the ISI table directly by putting a 1Hz 1mm injection into the Y isolation loop error point. 

Driving the path length, we both listened and had a live spectrum running. We saw no evidence of scatter in either OMC trans or MICH_IN1.

We will need to think if there is another configuration (available to use without arms) that will be more sensitive to backscatter.

Comments related to this report
nicolas.smith@LIGO.ORG - 16:52, Thursday 02 July 2015 (19433)

I forgot to mention that we turned on the AS fast shutter and OMC pzt high voltage supplies for HAM6.

nicolas.smith@LIGO.ORG - 20:22, Friday 10 July 2015 (19563)

This measurement didn't work because I was wrong about the calibration. The isolation loop error points are in nanometers, not micrometers. So we were moving the table 1000 times less than I thought.

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