The psinject and run_tinj are now under control of monit.  

Changes were made to the SOURCEME_LHO.sh script to correct paths to shared libraries, changes checked in.  Recompiled run_tinj and tinj using instructions in the source files.

Final state, psinject and run_tinj are not running, but under monit control. The output of the H1CALCS_INJ_HARDWARE filter has been turned on, with no injections running.

The script finished right before an EQ knocked us out of lock.  Attached are results, we can decide if we are keeping these decouplings durring the maintence window.

The three changes made by the script which I would like to keep are ETMX pit, ETMY yaw, and ITMY pit.  These three gains are accepted in SDF.  Since we aren't going to do the other work described in the WP, this is now finished. 

All the results from the script are:

ETMX pit changed from 1.263 to 1.069 (1st attachment, keep)

ETMX yaw reverted (script changed it from 0.749 to 1.1723 based on the fit shown in the second attachment)

ETMY pit reverted (script changed it from 0.26 to 0.14 based on the 3rd attachement)

ETMY yaw changed from -0.42  to -0.509, based on fit shown in 4th attachment

ITMX no changes were made by the script, 5th +6th attchments

ITMY pit (from 1.37 to 1.13 based on 7th attachment, keep)

ITMY yaw reverted (changed from -2.174 to -1.7, based on the 8th attachment which does not seem like a good fit)

By the way, the script that I ran to find the decoupling gains is in userapps/isc/common/decoup/run_a2l_vII.sh  Perhaps next time we use this we should try a higher drive amplitude, to try to get better fits.

I ran Hang's script that uses the A2L gains to determine a spot position (alog 19904), here are the values after running the script today. 

I also re-ran this script for the old gains, 

So the changes amount to +0.4 mm in the horizontal direction on ETMY, -0.9 mm in the vertical direction on ETMX, and -1.1mm in the vertical direction on ITMY.  

Please be aware that in my code estimating beam's position, I neglected the L2 angle -> L3 length coupling, which would induce

an error of l_ex / theta_L3, 

where l_ex is the length induced by L2a->L3l coupling when we dither L2, and theta_L3 is the angle L3 tilts through L2a->L3a.

Sorry about that...

Laura Nuttall, Marissa

I've repeated what Laura did in alog 21820 for this time, to compare the glitch rate between times that did and did not have the DHARD Y boost and determine whether this should have much of an impact on the transient searches' backgrounds. Unfortunately, this lock segment had some really bad RF45 noise so it's not ideal for evaluating glitch rates (since a lot of this time will be cut out from the search backgrounds), but it's what we have...

I've attached the omicron glitchgrams and trigger rates for the time that the filter was turned on, and for the same amount of time just after it was turned off. The overall rate of low SNR triggers is about the same during both segments, with some times of increased rate of higher SNR triggers while the filter was engaged, most likely due to the RF45 noise. Similarly, the glitchgrams' structures do not appear significantly different between the two segments, besides the awful RF45 times.

From this comparison, I would agree with Laura's earlier conclusion that this filter does not appear to have a significant effect on the background.

Looking back 16 days we discovered 2 more cases of the IMC_LOCK guardian turning on the ISS PID loop during a NOMINAL_LOW_NOISE (and observing) lock stretch.  Attached is the 16 day trend and the 2 examples.  The 2nd example was 30 hours into last week's 46 hour lock stretch.  Also note, in the 16 day trend, the continued power discrepancy from lock to lock.

Looking at the 16 day trend, by eye it seems the ISS diffracted power is hugging the upper threshold of 10% more often then not, hovering around 9%.  This might be normal acceptable behavior, however we were surprised to see that a PID loop was increasing power in the middle of an observing lock.  Will follow up with commissioners.

What do the in- and out-of-loop signals for the outer loop look like during these events? (I.e., SUM14 and SUM58.)

B. Weaver, J. Kissel,

Not sure what Evan wants with the "SUM14" and "SUM58" channels, so I found what channels are stored in the frames for the ISS, and used my vague knowledge of how the ISS SECOND LOOP works, and chose
H1:PSL-ISS_SECONDLOOP_SUM14_REL_OUT_DQ
H1:PSL-ISS_SECONDLOOP_SUM58_REL_OUT_DQ
and reproduced Betsy's plots with trends of those channels in addition to the original channels. 

I'll leave it to Evan to interpret the results, 'cause we don't know how.

Let us know if you need anything different, Evan (or on a different scale, or whatever). 

Can you add a plot of the amplitude and phase of 36MHz signal that is common to all four quadrants when there's no misalignment?

As requested, here are plots of the 36MHz signal that is common to all quadrants at the ASWFSA and ASWFSB locations in the simulation. I also checked whether the "sidebands on sidebands" from the series modulation at the EOM had any influence on the signal that shows up here: apparently it does not make a difference beyond the ~100ppm level. 

At Daniel's suggestion, I adjusted the overall WFS phases so that the 36MHz bias signal shows up only in the I-phase channels. This was done just by adding the phase shown in the plots in the previous comment to both I and Q detectors in the simulation. I've attached the ASWFS sensing matrix elements for MICH (BS) and SRC2 (SRM) again here with the new demod phase basis. 

**EDIT** When I reran the code to output the sensitivities to WFS spot position (see below) I also output the MICH (BS) and SRC2 (SRM) DOFs again, as well as all the other ASC DOFs. Motivated by some discussion with Keita about why PIT and YAW looked so different, I checked again how different they were. In the outputs from the re-run, PIT and YAW don't look so different now (see attached files with "phased" suffix, now also including SRC1 (SR2) actuation). The PIT plots are the same as previously, but the YAW plots are different to previous and now agree better with PIT plots.

I suspect that the reason for the earlier difference had something to do with the demod phases not having been adjusted from default for YAW signals, but I wasn't yet able to recreate the error. Another possibility is that I just uploaded old plots with the same names by mistake. 

To clarify the point of adjusting the WFS demod phases like this, I also added four new alignment DOFs corresponding to spot position on WFSA and WFSB, in ptich and yaw directions. This was done by dithering a steering mirror in the path just before each WFS, and double demodulating at the 36MHz frequency (in I and Q) and then at the dither frequency. The attached plots show what you would expect to see: In each DOF the sensitivity to spot position is all in the I quadrature (first-order sensitivity to spot position due to the 36MHz bias). Naturally, WFSA spot position doesn't show up at WFSB and vice versa, and yaw position doesn't show up in the WFS pitch signal and vice versa. 

For completeness, the yaxis is in units of W/rad tilt of the steering mirror that is being dithered. For WFSA the steering mirror is 0.1m from the WFSA location, and for WFSB the steering mirror is 0.2878m from the WFSB location. We can convert the axes to W/mm spot position or similar from this information, or into W/beam_radius using the fact that the beam spot sizes are at 567µm at WFSA and 146µm at WFSB.

As shown above the 36MHz WFS are sensitive in one quadrature to spot position, due to the constant presence of a 36MHz signal at the WFS. This fact, combined with the possibility of poor spot centering on the WFS due to the effects of "junk" carrier light, is a potential cause of badness in the 36MHz AS WFS loops. Daniel and Keita were interested to know if the spot centering could be improved by using some kind of RF QPD that balances either the 18MHz (or 90MHz) RF signals between quadrants to effectively center the 9MHz (or 45MHz) sideband field, instead of the time averaged sum of all fields (DC centering) that is sensitive to junk carrier light. In Daniel's words, you can think of this as kind of an "RF optical lever".

This brought up the question of which sideband field's spot postion at the WFS changes most when either the BS, SR2 or SRM are actuated.

To answer that question, I:

• Added 18MHz and 90MHz "WFS" to the Finesse model.
• Phased these new "WFS" so that all the 18MHz or 90MHz "sum" signals show up in the I-phase (see first two plots).
• Plotted the new "WFS" responses to BS, SR2 and SRM pitch and yaw (normalized by their "sum" signal), as a function of SR3 RoC (see the rest of the plots).

Some observations from the plots:

• 90MHz "WFS" show much more response to SRC1 (SR2) and SRC2 (SRM) tilts than 18MHz "WFS". This is somewhat intuitive, because the 45MHz sidebands are resonant in the SRC and the SRC eigenmode may be more sensitive to SR alignments than a beam traced through "single bounce" style.
• The 90MHz response to SRM/SR2 tilt remain very much in the I phase, with almost no signal in the Q-phase. 
• 18MHz "WFS" show more response to MICH (BS) than the 90MHz "WFS". This is problably because a BS tilt causes a large coupling of 9MHz HG10/01 mode from the PRC to the SRC relative to the amount of 9MHz HG00 mode already in the SRC (due to high Michelson reflectivity + SRC non-resonance for 9MHz HG00). Since I normalize to the total sideband power, this looks like a bigger response in 18MHz than 90MHz.
• The 18MHz response to BS tilt is mostly in the Q phase. I'm not sure exactly how to interpret this, but my naive guess is that it's related to the BS tilt being a "differential" mode tilt for the X and Y arms of the small Michelson.

I looked again at some of the 2f WFS signals, this time with a linear sweep over alignment offsets rather than a dither transfer function. I attached the results here, with detectors being phased to have the constant signal always in I quadrature. As noted before by Daniel, AS18Q looks like a good signal for MICH sensing, as it is pretty insensitive to beam spot position on the WFS. Since I was looking at larger alignment offsets, I included higher-order modes up to order 6 in the calculation, and all length DOFs were locked. This was for zero SR3 RoC offset, so mode matching is optimal.