Charge Measurement Update; Pre-ETMX TMDS Use

J. Kissel

First regular charge measurement after O2; last regular charge measurement before the the Test Mass Discharge System (TMDS) tomorrow on ETMX. Trends are consistent with everything that has been true since the July 6th 2017 EQ (I've added by-hand, eye-ball trend lines to guide the eye). The reason I've been wishy-washy on claiming whether there was a jump in effective bias voltage: some quadrants don't show a change after July 6th, others do, and it depends on the suspension. We should really take the time to convert these results into a geometric display of the optic face #between02and03squadgoals. 
 
I won't display the relative actuation strength plots any more, since we don't really care when we're not in an observation run and they don't show much more information than the effective bias voltage plots. If someone still wants to see them, just post a comment to this log with your request.

remote access permit system disabled

Jonathan, Dave:

We have disabled the remote LHO CDS login permit system, Yubikey holders can now log into LHO CDS without having to get the operator to open a permit. The access system is running in monitor-only mode, remote logins are being displayed on the CDS Overview MEDM.

h1susitmy and daq restart

Sheila, Dave:

Sheila corrected and restarted the h1susitmy model. The change required a DAQ restart, which was done.

2017_08_28 11:53 h1susitmy
2017_08_28 12:00 h1broadcast0
2017_08_28 12:00 h1dc0
2017_08_28 12:02 h1fw0
2017_08_28 12:02 h1fw1
2017_08_28 12:02 h1fw2
2017_08_28 12:02 h1nds0
2017_08_28 12:02 h1nds1
2017_08_28 12:02 h1tw1

The problem was a typo -- the ITMX FF control signals were going to both ITMX and ITMY. This is likely the cause of our poor ~20-200 Hz performance overnight. Now fixed and on our way back up through initial alignment.

PSL Weekly Report - 10 Day Trends FAMIS #6163

Nothing to report other than the normal, weekly current adjustments and the marginally twitchy chiller plots.

PCalY Rx Signal Stability

Based on some concern about various clipping possibilities in EndY, Travis S. removed irises in the EY Rx side on Aug 15 (see WP 7111; this says EX but was fixed to say EY in paper book). When Sudarshan evaluated calibration data after this (alog 38235), he found that Rx calibration values had returned to "non-clipping" values from prior to end of May.

I wanted to confirm that this was true over time, not just on the day of calibration, so I pulled up the last 6 months on Dataviewer; see results in the attached photo. It seems the Rx PD does flatten out over the 2 weeks since iris removal.

Rick, Travis, and I are currently under the assumption that this indicates clipping at the iris due to small apertures being aligned at high incidence angles. However, this is far from conclusive and will need to be monitored for several more weeks or months. This also does not provide any clues as to the cause of the monotonic drop in output voltage since June.

Both ETM HWS Measurements Done

First I got the IFO to DC Readout so that IR is resonant in both arms, then opened the ALS shutters and misaligned PZT2 on each arm according to  ALOG 35979.

The reference images were taken at 04:13:00 UTC (21:13 PST) on 2017-08-28.  Then power up occurred at 04:21:50 UTC and reached nominal power at 04:24:30 UTC. 

I've shuttered the ALS at  05:42:00 UTC and reset the PZT loops to their nominal bias values.

in lock charge measurements

On friday Thomas and I ran excitations on all 4 ESDs in order to measure the 4 coefficients in this equation for the force applied by the ESDs (G1600699) Equation 2:

F = α (V_b-V_s)² +β (V_b+V_s)+ β _2(V_b-V_s)+γ (V_b+V_s)²

The first 2 excitations for each suspension were on the bias path with no signal voltage so that the linear response is:

F = [β+β_2+2(α+γ)V_b] δV_b

The bias path was excited twice, first with the normal bias of 380 V on and second with no bias. Then the script excited the signal path which gives a linear response of:

F = [β-β_2+2(α+γ)V_b+2(α-γ)V_s] δV_s

This path is excited 3 times, once with no DC offset on any electrodes, once with an offset of 7.6Volts on the signal electrodes, and once with the bias at its normal value of 380V.

The first 4 of these measurements allow us to make a complete measurement of all four coefficents, α, β β_2, and γ The fifth measurement is redundant and could be skipped, I used it as a sanity check.  I am still worried that I have some signs wrong which are making these results confusing.  

	ETMX	ETMY	ITMX	ITMY
α (N/V^2)	2.1e-10	2.0e-10	8e-11	5.5e-11
β(N/V)	-9.9e-10	2.0e-8	1.0e-8	5.6e-9
β_2 (N/V)	2.8e-9	3.2e-8	-4.2e-9	-8.5e-9
γ	1.5e-10	1.2e-10	-4.0e-11	-1.2e-11
V_eff = (beta-Beta2)/(2*(alpha-gamma))	-31 V	-75 V	60 V	105 V

All of the scripts needed for taking the measurement and getting the coefficents are in userppas/sus/common/quad/scripts/InLockChargeMeasurements/

Tourists from Czech Republic on site unescorted

1515 -1915 hours local -> Kyle R. on site

At around 1800 hrs. local as I was walking between the VPW and the OSB, I happened upon 15 non-escorted people, all wearing matching T-shirts taking a group photo by the BT section display outside of the exterior OSB Control Room Hallway door.  They said that were with "AldeBaran alph Tau" from the Czech Republic and were touring the Western USA - mostly scientific points of interest. They demonstrated a familiarity with LIGO and had already made it past the "ISIS" gate, so I gave them an impromptu tour.  I escorted them into the Control Room (Sheila D. present) then on to the overpass.  Afterwards, I walked them to their cars.  They hoped to call on Monday and arrange for an "actual" tour.  They also said that LHO was their last stop before flying out of Portland OR. in two days time.  

h1lsc, h1omc, h1susitmx and h1susitmy model changes, DAQ restart

WP7120 Sheila and Dave:

The h1lsc model was modified to add two new SHMEM IPC senders. The h1omc model was modified to add two new SHMEM receivers (for the new h1lsc channels) and two new PCIE (Dolphin) sender channels. Each of the SUS ITM models were modified to add one new PCIE receiver channels to receive from h1omc.

The models were compiled and installed, the modifications to H1.ipc is shown below.

The models were restarted in the order: h1lsc, h1omc, h1susitmx, h1susitmy.

Because IPC receivers had been added, their slow channels were added to the DAQ INI file, requiring a DAQ restart.

After the DAQ was restarted, I discovered two things:

1. I forgot to check the write status of h1tw1 before restarting. I have checked that h1tw1 was writing raw minute trends every 5 minutes.

2. The EDCU did not come back to a GREEN status. The reason is that a new Guardian node ALS_DIFF_ETMY_ESD had been created (and added to the Guardian DAQ INI file) but is not being ran. We'll fix this tomorrow, for now the EDCU is RED, and it is missing these 19 guardian channels. The disconnected channel list is shown below.

ALS_DIFF_ETMY_ESD Guardian DAQ channels (disconnected):

H1:GRD-ALS_DIFF_ETMY_ESD_VERSION

H1:GRD-ALS_DIFF_ETMY_ESD_EZCA

H1:GRD-ALS_DIFF_ETMY_ESD_OP

H1:GRD-ALS_DIFF_ETMY_ESD_MODE

H1:GRD-ALS_DIFF_ETMY_ESD_STATUS

H1:GRD-ALS_DIFF_ETMY_ESD_WORKER

H1:GRD-ALS_DIFF_ETMY_ESD_LOAD_STATUS

H1:GRD-ALS_DIFF_ETMY_ESD_ERROR

H1:GRD-ALS_DIFF_ETMY_ESD_CONNECT

H1:GRD-ALS_DIFF_ETMY_ESD_EXECTIME

H1:GRD-ALS_DIFF_ETMY_ESD_STALLED

H1:GRD-ALS_DIFF_ETMY_ESD_NOTIFICATION

H1:GRD-ALS_DIFF_ETMY_ESD_NOMINAL_N

H1:GRD-ALS_DIFF_ETMY_ESD_REQUEST_N

H1:GRD-ALS_DIFF_ETMY_ESD_STATE_N

H1:GRD-ALS_DIFF_ETMY_ESD_TARGET_N

H1:GRD-ALS_DIFF_ETMY_ESD_OK

H1:GRD-ALS_DIFF_ETMY_ESD_ARCHIVE_ID

H1:GRD-ALS_DIFF_ETMY_ESD_TIME_UP

H1.ipc additional channels:

[H1:LSC-OMC_ITMX]

ipcType=SHMEM

ipcRate=16384

ipcHost=h1lsc0

ipcModel=h1lsc

ipcNum=59

desc=Automatically generated by IPCx.pm on 2017_Aug_27_13:36:33

 

[H1:LSC-OMC_ITMY]

ipcType=SHMEM

ipcRate=16384

ipcHost=h1lsc0

ipcModel=h1lsc

ipcNum=60

desc=Automatically generated by IPCx.pm on 2017_Aug_27_13:36:33

 

[H1:OMC-ITMX_LOCK_L]

ipcType=PCIE

ipcRate=16384

ipcHost=h1lsc0

ipcModel=h1omc

ipcNum=385

desc=Automatically generated by IPCx.pm on 2017_Aug_27_16:09:43

 

[H1:OMC-ITMY_LOCK_L]

ipcType=PCIE

ipcRate=16384

ipcHost=h1lsc0

ipcModel=h1omc

ipcNum=386

desc=Automatically generated by IPCx.pm on 2017_Aug_27_16:09:43

 

BS ST1 CPS trips

I came in to lock the IFO for Adam's injections which are scheduled for 2 hours from now, (38380), but have had about 4 BS ISI ST1 CPS trips in the last hour. 

Two of these might have happened while the BS was isolating stage 2 (I have not double checked) but at least one happened while we were just sitting in CHECK_IR (no feedback to the BS sus, ISI state should not have been changing).  The screenshot attached is for that most recent trip in CHECK_IR

Edit:  Made it to a fully locked interferometer and was engagning ASC when it happened again, again it was a glitch in the ST1 H3 CPS.  Second screenshot 

Edit again: This seems very similar to the situation described in 37499, 37522 the third screenshot shows the glitches getting worse over the last 1:40 minutes.  Jim describes power cycling the satlite racks which seemed to make the problem go away last time. 

Another update: I power cycled the 3 top chassis in the CER rack SEI C5, these are labeled BSC ISI interface chassis and have cables going to BSC2 CPSs, GS13s and L4C's.  The ISI has not tripped in about 20 minutes, I am relocking but paused to damp violin modes.

Another attempt at Detchar Safety Injections

Sheila plans to come in and lock the IFO this afternoon, so that I can try to finish these detchar safety injections. I've schedule 7 injections, the first one will begin at 16:06:22 PDT, and the last at 16:51:22 PDT. Here is the update to the schedule:

1187824000 H1 INJECT_DETCHAR_ACTIVE 0 1.0 detchar/detchar_27July2017_PCAL_{ifo}.txt
1187824450 H1 INJECT_DETCHAR_ACTIVE 0 1.0 detchar/detchar_27July2017_PCAL_{ifo}.txt
1187824900 H1 INJECT_DETCHAR_ACTIVE 0 1.0 detchar/detchar_27July2017_PCAL_{ifo}.txt
1187825350 H1 INJECT_DETCHAR_ACTIVE 0 1.0 detchar/detchar_27July2017_PCAL_{ifo}.txt
1187825800 H1 INJECT_DETCHAR_ACTIVE 0 1.0 detchar/detchar_27July2017_PCAL_{ifo}.txt
1187826250 H1 INJECT_DETCHAR_ACTIVE 0 1.0 detchar/detchar_27July2017_PCAL_{ifo}.txt
1187826700 H1 INJECT_DETCHAR_ACTIVE 0 1.0 detchar/detchar_27July2017_PCAL_{ifo}.txt

The IFO should be left out of observation mode. Also, I'm not sure if the PCALX 1500Hz line gets turned back on, but this also needs to be turned off. Simply typing the following on the command line will do the trick:

caput H1:CAL-PCALX_PCALOSC1_OSC_SINGAIN 0
caput H1:CAL-PCALX_PCALOSC1_OSC_COSGAIN 0

% Plot hardware injections
fnm = 'detchar_27July2017_PCAL_H1.txt';
data = load(fnm);
t = 0:1/16384:(length(data)-1)*1/16384;

figure;
plot(t,data)
xlabel('time [s]')
ylabel('amplitude [h]')
title(strrep(fnm,'_','\_'))
orient landscape
saveas(gcf,'injections.pdf')

% Print times of injections
t_start = 1187824000+0.5;
times = t_start:3.0:t_start+106;
fprintf('%.2f
',times)

Ops Day Shift Summary

TITLE: 08/25 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Commissioning
INCOMING OPERATOR: None
SHIFT SUMMARY: Last shift of O2! No issues until Beckhoff SDF died during Adam's detchar safety injections. Jonathan has restarted h1build and it is currently running a file system check. Intention bit set to commissioning. Observatory mode set to commissioning. IFO at NLN.
LOG:

16:02 UTC Powercycled video2. MEDM screen updates were intermittent.
16:07 UTC Restarted the range integrand DMT that is displayed on video0. It had been running locally on video0 instead of through ssh on nuc6.
17:23 UTC Gave Adam M. remote access to cdsssh and h1hwinj1.
18:50 UTC GRB verbal alarm. Confirmed with LLO.
15:00 UTC End of O2! Set observatory mode to calibration. Changed INJ_TRANS guardian node to INJECT_SUCCESS.
22:43 UTC Adam M. starting detchar safety injections. Set intent bit to commissioning. HFD to mid X to check on RFAIR box.
~23:09 UTC Beckhoff SDF died. IFO_LOCK guardian node went into error (lost connection to SDF channels). Adam's injections interrupted. Jonathan investigating.
23:23 UTC Jonathan restarted h1build and it is running a file system check. Adam canceling remainder of injections. Transitioned observatory mode to commissioning.

15:00 UTC should be 22:00 UTC.

Lens change per lock seemed to increase in June - possible change in absorption?

[Aidan]

I've been investigating the apparent increase in range that occurred this morning when CO2X was turned off. This would seem to indicate that either (a) the CO2 laser is somehow misaligned/or deformed and causing a very poor lens, or (b) the present level of lensing (SELF heating + CO2) is too much. It's worth noting that the requested (and delivered) levels of CO2X laser power haven't changed significantly over the last four or five months.

If we assume (b) and also that the better range in the past is partially due to a better thermal state, then the conclusion is that either the effective CO2 lens or the SELF heating lens has increased.

I've gone back and looked at the HWSX spherical power data (H1:TCS-ITMX_HWS_PROBE_SPHERICAL_POWER) from two months around the period of the earthquake. The relevant value here is the spherical power change per lock (the difference between the upper and lower levels that are obvious in the time series which shows the transient lens from SELF heating and CO2 laser changes). There is an interesting period form 22-June to 7-July where this trends upwards by approximately 25 micro-diopters (or about 50%). This indicates that the apparent lens change per lock seen by the HWS is increasing significantly.

Two factors also play into this. (1) the CO2 laser is being turned on and off during this time (to keep the thermal state warm when the IFO has lost lock). However there is no significant change in the CO2 power level behaviour over the corresponding time range. (2) we know there is already a point absorber on ITMX as well as uniform absorption. The spherical power value is fitted to the low spatial-frequency lens. The presence of a known high spatial frequency point in the wavefront complicates this. For example, it's possible that the HWS alignment may be drifting and the point absorber is contributing more to the total spherical power value. This obviously needs to be investigated further by looking at the stored gradient fields.

However, it does seem that there is a real effect going on as the range got much better (~15% better) when the CO2 laser turned off. 

TMDS training session at X-end

Rai W., Mike Z., Daniel S., Jeff K., Chandra R., Kyle R. 

Today the TMDS Gas Delivery Table was transported to the X-end VEA and set it up for operation.  The actual Surface Discharge Ionizer was mounted on a stand for today's demonstration purposes.  Nominally, it would be mounted to the dedicated TMDS port of BSC9's East Door.  The Vent/Purge air supply was ran and dry air supplied to the TMDS setup.  Prior to exposing the Ionizer to the conditioned air supply, the plumbing connection at the Ionizer was decoupled and connected to a test setup that facilitated the measurement of > 0.3 micron and > 0.5 micron particulate in the conditioned air. The air line was then re-coupled to the Ionizer.  An approximate 50/50 mix of Ethylene Glycol to Alcohol along with "chunks" of dry ice was used as a cold trap to the path.  

Rai W. gave an overview of the theory and a detailed tutorial as to the operation of the setup.  Daniel S. and Jeff K. noted details related to the ion production while Kyle R. and Chandra R. noted detail related to the vacuum related issues.  

The Ionizer setup performed satisfactorily (with caveats) at making comparable amounts of positive and negative ions.  

The plan now is to connect the Ionizer to BSC9 and perform an actual discharge of the ETMx during next Tuesday's maintenance day.  

My notes from today; 

1. Oscillations were noted and attributed to electronics design -> Daniel S. will address.  
2. Rai W. requested that we provide a means of support to take the weight of the Ionizer when mounted to the 1 1/2" valve on the BSC -> Kyle R. will address.  
3. Confirmation of the preferred means to pump to rough vacuum the X-end VE between cycles of discharge gas admission -> Chandra R. will address.  

Refer to Figure 1 of T1400713, TMDS design document for elements of setup.

A couple of useful videos of the oscilloscope readouts during the experiment:

Lesson 1: Control and readback of the electrometer from the TMDS inferface chassis, D1500152.
    Rai has set up the readback of the electrometer with the square-wave input shown on the blue trace, and the electrometer readback in yellow. One is looking for an even balance in voltage from the positive and negative ions. The electrometer has a negative voltage bias at the time of recording, so it appears as though we're getting more positive than negative ions, but, rest assured, we're good. 

Lesson 2: Demonstration of ionic discharge against TMDS chamber walls, if HV supply to ion generator is too high.
    The readback of the HV current is shown on the yellow trace. The video starts out with the ion generator discharging, as is evident by the rattiness of the waveform. At the last few seconds of the video, he reduces the VARIAC HV transformer gain, bringing the ion generator back to the desired level.

Lesson 3: Demonstration of electrometer readback once HV voltage is reduced
    Once the HV is tuned with the VARIAC, with the initial max amplitude of the square wave generator, then the square wave amplitude may be reduced to ~ 3 V pkpk (assuming a flow rate of about 30-50 [mL/s ?? not sure about those units]). Once we did this, we saw evidence for a ~3 MHz oscillation on the electrometer readback. Investigating the circuit drawing for the electrometer board (D1500061), Daniel and Mike agreed to replace the readback's output resistors R9 & R10 with ~100 [ohm] resistors. 
This has been done already, and the electrometer has been reinstalled

Lesson 4: Final setup of readback / monitor system, in the "ready to discharge into chamber" configuration.
    Once again, Rai demonstrates the control of the HV VARIAC and the desire to keep the ion generator current readback from any rattiness in its waveform, which is indicative of ionic breakdown discharge against the TMDS chamber walls.

I attach a ton more pictures of the setup as well. Hopefully the filenames are a good enough caption.

Desired gas flow rate 30 - 50 Liters per Minute (LPM)