Michael, Krishna

In this post, I'll try to summarize the work accomplished on the BRS-Y (2) and BRS-X (1) over the last few weeks.

1) BRS-Y:

The instrument including the box in the VEA and the Beckhoff computer/modules were installed (26242, 26265, 26276) . The tilt transfer function was measured and we then adjusted the center of mass to minmize 'd'. We then remeasured the transfer function to confirm that d was indeed small. This isn't particularly necessary for the goal of tilt-subtraction but does allow us to study the tilt from surface waves during an earthquake.

Tilt-subtraction for the ground seismometer has been shown to be very effective under 20-30 mph winds at both EY and EX in the 10 mHz to 1 Hz band. We have shown some modest improvements to ISI motion using sensor correction in the 'along-the-beam' direction in the 0.1-1 Hz band (as seen be ST1 T240)  without any increase to the total rms motion (as measured by the CPS). Both of these are local sensors and it would be interesting to test these configurations with the interferometer. There are also likely other ways to use the BRS signals which may prove more beneficial.

The C# and the Beckhoff PLC code for BRS-Y have been uploaded to svn under slowcontrols. This system is more robust than the one at EX and allows for greater CDS integration and control. Several of the BRS parameters (such as damping on/off, damping thresholds) can be controlled through EPICS commands. For example, typing " caput H1:ISI-GND_BRS_ETMY_USER 0" disables damping and " caput H1:ISI-GND_BRS_ETMY_USER 1" enables it.

We just discovered today that one of the two capacitive actuators was shorted internally and cannot be used. The damping is thus asymmetric and less strong. There are also other minor issues with it but it still meets its main goal of keeping the amplitude small.

The vcauum system is working well. The ion pump current is ~25 microamps, corresponding to a pressure of ~1.5 X 10^(-7) torr. The corresponding current for BRS-X is 14 microamps after ~two years.

The DC position of the beam-balance has been slowly settling with a very long time constant (~10 days). The attached plot shows the DRIFTMON channel over the last 16 days. The two main spikes followed by DC shifts were caused by us changing the DC position using a small moveable rod on the beam-balance. Based on the trend we expect it to drift down and then approach an equlirbrium value within the range of the autocollimator (+/-16k counts on the Y-axis).

2) BRS-X:

BRS-X was restarted from hibernation and works well for the most part.

The startup procedure for the code has been simplified. There are now two shortcuts on the BRS-X laptop's desktop screen - the one labelled "Damping ON" runs the software with damping enabled (DC subtraction is automated) and the other one runs with damping diabled and 2.5 V for the DAMP_CTRL channel, which can be used to reset the damper, if needed. A recurring problem with it is the damper turn-table vibrations causing the beam-balance to ring up. A new Beckhoff computer/modules and a GigE camera have been/will be ordered for it and we will develop a new smoother turn-table which will address these problems.

1/2 open LLCV bypass valve, and the exhaust bypass valve fully open.

Flow was noted after 1 minute and 37 seconds, closed LLCV valve, and 3 minutes later the exhaust bypass valve was closed.

Extended, routed and terminated CDS signal cable for HAM6 annulus ion pump controller.

Apparently, I missed this task in my queue. I "shot-the-gap" with these.

Reference FAMIS #4668 

Mia culpa, I changed the name of the second spare PEM ADC channel at the corner station to H1:PEM-CS_ADC_4_27_16K_OUT_DQ but forgot to change the actual rate in the DAQ block. I corrected this, restarted h1pemcs and restarted the DAQ.

On the DAQ restart: mx_stream restarted needed on h1oaf0 and h1pemmx. h1fw1 kernel crashed on startup, needed power cycle.

Set H0:VAC-EY_CP7_LIC400_LLCV_POS_CTRL_PCT_DEAD_BAND to 0.5.

Apologies for the late entry.

C. Cahillane

Per Jeff's suggestion, I have detrended the calibration time-dependent kappas to get the true all of O1 uncertainty associated with the kappas.

This was done to eliminate the spikes in calibration uncertainty we would see from changes in the detector, such as ESD bias flips.

I detrended by finding the median kappa for a range of 100 kappas around a specified gpstime.  Then I would subtract the original kappa from the found median.  I then took the standard deviation over all of O1 from the detrended kappas.  These are the numbers reported in the histogram titles. 
From this method, we get sub-percent and sub-degree uncertainty, due to the massive numbers of kappas we have.  I think this is fine as long as we understand why the detector configuration changed at every kappa-jump.

To see the LLO kappa detrends, please see LLO aLOG 25677

Ops EVE Shift. All time in UTC.

23:23 Jeff K. to EY to kick on ETMY ESD driver.

23:30 Dave restart SUS ETMX PI and PEM CS (added 2 mic at 16 kHz) models.

23:52 Jeff K. back. Power supply had tripped.

00:50 Nutsinee and Kiwamu walked around the LVEA to check on viewports. All of them are covered. We turned the CO2 controller boxes on so we can do some measurement.

02:23 Everybody's gone home. I think I'm going to end my log here.

Also I haven't done the measurement I wanted to do so the CO2 controller boxes are still on (but no output to the test masses. The laser is turned off on medm screen).

I have added SRM, SR2 and SR3 to the ADS (alignment dither system) part of the ASC.  All necessary IPCs were already there, they were just grounded.  Now we can send the dither signal to the SR mirrors, and also actuate on them with the demodulated signal if we so choose.  We'd like to use this (at least looking at the demodulated sigal) to help us find the correct operating point for the SRC ASC signals.

While I was doing that, I also added the ability to blend the DHARD error signals, in case we decide to do that after we try CHARD error signal blending.

MEDM screens for the DHARD blending are done, although I have not yet completed the screen modifications for the ADS.

Dan completed the Q-Logic switch and SATA-BOY raid move from LSB to warehouse. The frame gap on h1fw0 is 12:01 - 17:58 PDT.

We installed Jenne's latest h1asc model and restarted the DAQ. h1fw1 did not start cleanly via monit and h1fw0 was having issues around the restart time. The framewriters did not sync-up with each other, maybe an issue in the time order of the asc and daq restarts. I did a second DAQ restart (with subsequent h1fw1 panic crash) which synced everything up. Moral of the story, if a fw is misbehaving, do not restart the DAQ until it is stable.

The power stabilisation was worked on today.  No real success to speak of.
The offset for the AOM drive signal was adjusted to diffract ~5W of light.

The servo was intermittent at low frequencies.  Examination of the photodiode
monitor signals showed changes in level at low frequencies.  This might be due
to interference between the main beam of the laser and some junk light from the
laser, even though the photodiodes are located after the pre-modecleaner.  The
symptoms seem to be eased when the pre-modecleaner servo gain was reduced.
However doing that reduces the unity gain of the pre-modecleaner servo.

We will take another look at the output of the laser tomorrow.




Jason, Peter

Tega and Ross installed new h1susetmxpi model. I modified h1pemcs for Robert, renaming the spare ADC DAQ channels with their datarate, and increasing the rate of the first two from 2kHz to 16kHz.

A new edcu file H1EDCU_BRSEY.ini was added to the DAQ, this adds the new Beckhoff EY BRS slow channels.

After both models were restarted, the DAQ was restarted. The DAQ is still running with only h1fw1 while LDAS maintenance is ongoing.

Extended, routed and terminated CDS signal cable for HAM1 annulus ion pump controller.

I started these nodes and will have them run overnight to see how they handle. The purpose of these nodes is to watch their respective BRS and report what state it is in, in the node's state (ie. if the damper is on, the state will be DAMPER_ON). In the future, these nodes will help the SEI configuration nodes to determine if the BRS is in a good condition to be used for sensor correction.

We got the EPICS IOC running on the BRSY computer and now have a collection of EPICS channels which hold detailed information about BRSY. Below is a list of the channels with some brief descriptions. For more detailed descriptions along with troubleshooting guide see T1600103.

Channel List:
H1:ISI-GND_BRS_ETMY_DAMPTIMEOUT, damping time out in number of cycles, read/write
H1:ISI-GND_BRS_ETMY_AMPBIT, amplitude status
H1:ISI-GND_BRS_ETMY_BOXBIT, BRS electronics box status
H1:ISI-GND_BRS_ETMY_CBIT, C# running bit
H1:ISI-GND_BRS_ETMY_DAMPBIT, Damping state
H1:ISI-GND_BRS_ETMY_MODBIT, Beckhoff modules status
H1:ISI-GND_BRS_ETMY_USER, User damping logic control, read/write, (0 stops damping from ever turning on, 1 allows damping to turn if necessary)
H1:ISI-GND_BRS_ETMY_CAMERA, Camera status
H1:ISI-GND_BRS_ETMY_LIGHTSRC, Light source status
H1:ISI-GND_BRS_ETMY_TEMPL, Left temperature sensor in 0.01℃
H1:ISI-GND_BRS_ETMY_TEMPR, Right temperature sensor in 0.01℃
H1:ISI-GND_BRS_ETMY_VEL, Sqrt(velocity)
H1:ISI-GND_BRS_ETMY_HIGHTHRESHOLD, Damping high threshold, read/write, above which the damping turns on
H1:ISI-GND_BRS_ETMY_LOWTHRESHOLD, Damping low threshold, read/write, below which the damping timeout begins

Also, we've uploaded both the PLC code and the C# code to the SVN under slowcontrols.

Title:  04/13/2016, Day Shift 15:00 – 23:00 (08:00 – 16:00) All times in UTC (PT)
State of H1: IFO unlocked. HAM6 being pumped. Work on PSL is ongoing  
Commissioning: 
Outgoing Operator: N/A
 
Activity Log: All Times in UTC (PT)

15:00 (08:00) – Start of shift
15:44 (08:44) Christina & Karen – Going into LVEA for cleaning
15:52 (08:52) Kyle – Going into LVEA to move vacuum pump from north side of HAM6 
15:57 (08:57) Keita – Going to ISCT1 to do fit checking
16:09 (09:09) Peter – Going into LVEA to make measurements
16:14 (09:14) Gerardo – Going to Y-End to recover Pump cart
16:28 (09:28) Peter – Out of the LVEA
16:29 (09:29) Chris – Beam sealing on the X-Arm near the corner station
16:42 (09:42) Filiberto – Taking job shadows into CER
16:50 (09:50) Filiberto & Job shadows – Going to Mid-Y to prep for vacuum system changes
16:58 (09:58) Kyle – Out of the LVEA
17:05 (10:05) Gerardo – Back from End-Y
17:09 (10:09) Kyle & Gerardo – In LVEA craning the pump cart over the beam tube
17:15 (10:15) Peter & Jason – Going into the PSL enclosure
18:10 (11:10) Dale – Taking job shadows on LVEA tour
18:14 (11:14) John – Going to both mid stations to check property tags
18:38 (11:38) Dale – Out of LVEA
18:50 (11:50) Filiberto – Back from Mid-Y
18:52 (11:52) Filiberto – Going to Mid-X
19:06 (12:05) Dave & Jim – 	DAQ restart 
				Taking down FW0 for several hours to move disks
				Taking down NDS0 – May cause Guardian to crash	
19:15 (12:15) Filiberto – Back from Mid-X
19:19 (12:19) Kyle – Out of LVEA
19:29 (12:29) Jason & Peter – Finished in the PSL enclosure
19:31 (12:31) Jim – Restarting H0EPIC2 to fix a pegged CPU
19:49 (12:49) Jeff K. & Evan – Going to End-X to hunt for noise
20:51 (13:51) Krishna – Going to End-X for BRS code changes
21:40 (14:40) Filiberto – In Beer Garden working on Newtonian array
21:46 (14:46) Peter & Jason – In LVEA around PSL racks
21:55 (14:55) Chandra & John – In LVEA at GV3  
22:15 (15:15) Keita – Finished moving the ISCT6 table back into place at HAM6
22:18 (15:18) John & Chandra – Out of the LVEA
22:26 (15:26) Krishna – Back from End-X
22:58 (16:58) Jeff K. & Evan – Back from End-X


End of Shift Summary:

Title: 04/13/2016, Day Shift 15:00 – 23:00 (08:00 – 16:00) All times in UTC (PT)
Support: 
Incoming Operator: Nutsinee 

Shift Detail Summary: Chamber pump down continues at HAM6. The PSL team is working on a power stabilization problem located outside the PSL enclosure. Various other groups are taking advantage of the IFO being unlocked to address problems, upgrades, and fixes.  

Related alogs 26264. 26245

I did some follow-up tests today to understand the behavior of the DARM cavity pole. I put an offset in some ASC error points to see how they affect the DARM cavity pole without changing the CO2 settings.

I conlude that the SRC1 ASC loop is nominally locked on a non-optimal point (when PSL is 2 W) and it can easily and drastically changes the cavity pole. The highest cavity pole I could get today was 362 +/- a few Hz by manually optimizing the SRC alignment.

[The tests]

This time I did not change the TCS CO2 settings at all. In order to make a fair comparison against the past TCS measurements (26264, 26245), I let the PSL stay at 2 W. The interferometer was fully locked with the DC readout, and the ASC loops were all engaged. The TCS settings are as follows, TCSX = 350 mW, TCSY = 100 mW. I put an offset in the error point of each of some ASC loops at a time. I did so for SRC1, SRC2, CSOFT, DSOFT and PRC1. Additionally, I have moved around IM3 and SR3 which were not under control of ASC. All the tests are for the PIT degrees of freedom and I did not do for the YAWs. During the tests, I had an excitation line on the ETMX suspension at 331.9 Hz with a notch in the DARM loop in order to monitor the cavity pole. Before any of the tests, the DARM cavity pole was confirmed to be at 338 Hz by running a Pcal swept sine measurement.

The results are summarized below:

• SRC1, offset = from +400 to -300 cnts, cavity pole = from 350 Hz to 275 Hz
• SRC2 , offset = from +0.2 to -0.2 cnts, no change
• DSOFT, offset = from -0.03 to 0.03 cnts, no change in cavity pole, but a noticeable drop in the power recycling gain (41 --> 39).
• CSOFT, offset = from -0.03 to 0.03 cnts, no change in cavity pole, but a noticeable drop in the power recycling gain (41 --> 38-ish).
• PRC1, offset = from -0.1 to 0.1 cnts, no change in cavity pole, but a noticeable drop in the power recycling gain (41 --> 38-ish).
• IM2, some large offset, no change in cavity pole.
• SR3, offset = +/- 50 urad, no change in cavity pole or recycling gain.

The QPD loops -- namely CSOFT, DSOFT, PRC1 and SRC2 loops -- showed almost no impact on the cavity pole. The SOFTs and PRC1 tended to quickly degrade the power recycling gain rather than the cavity pole. I then further investigated SRC1 as written below.

[Optimizing SRC alignment]

I then focused on SRC1 which controlled SRM using AS36. I switched off the SRC1 servo and started manually aligning it in order to maximize the cavity pole. By touching PIT and YAW by roughly 10 urads for both, I was able to reach a cavity pole of 362 Hz. As I aligned it by hand, I saw POP90 decreasing and POP18 increasing as expected -- these indicate a better alignment of SRC. However, strangely AS90 dropped a little bit by a few %. I don't know why. At the same time, I saw the fluctuation of POP90 became smaller on the StrioTool in the middle screen on control room's wall.

In order to double check the measured cavity pole from the excitation line, I ran another Pcal swept sine measurement. I confirmed that the DARM cavity pole was indeed at 362 Hz. The attached is the measured DARM sensing function with the loop suppression taken out. The unit of the magnitude is in [cnts @ DARM IN1 / meters]. I used liso to fit the measurement as usual using a weighted least square method. 

By the way, in order to keep the cavity pole at its highest during the swept sine measurements, I servoed SRM to the manually adjusted operating point by running a hacky dither loop using awg, lockin demodulators and ezcaservos. I have used POP90 as a sensor signal for them. The two loops seemingly had ugf of about 0.1 Hz according to 1/e settling time. A screenshot of the dither loop setting is attached.