There was some suspicion that the REFL beam is somehow clipped on LSC REFL_A diode. Yesterday I made a long scan of RM1 and RM2, separately and at the same time.

LSC-REFL_A_LF is good, ASC-REFL_B too.

I had to move RM1 and/or RM2 by a large amount to make the LSC-REFL_A_LF drop.

ASC-REFL_B is also good, though the safe range is smaller than LSC (not surprising considering the short focal length lens in front of LSC diode).

ASC_REFL_A is unhealthy.

Something is wrong with SEG4.

It seems as if SEG4 has a lower trans impedance, in that when I steer the beam to SEG4 (all power falls on that segment) we get 18000 counts, but when I do the same thing to SEG1/2/3 they rail at 32k counts.

In the attached, the beam was in SEG3 at first, and I walked the beam to SEG4, then SEG1, then SEG2, and then back to SEG3 by turning RM1.

The problem seems to be in the WFS head, not in the WFS interface board. Connected the WFS output cable from the REFL_A head to REFL_B input and the problem is still there.

For the moment I adjusted the digital gain of SEG4 such that there's no coupling from PIT and YAW motion to the SUM (new H1:ASC-REFL_A_DC_SEG4_GAIN=1.9), but this needs to be investigated further.

The second attachment shows the REFLA SUM spectrum of before (green) and after (red) of the gain adjustment when I was modulating PIT of RM1 at 3.3Hz and YAW at 5Hz. For comparison, Blue/Brown are the REFLB SUM data which show no alignment coupling.

Could be the electronics in the head or the cable (one end of the differential signal is dead?). I hope that the diode is not damaged.

Though not impossible, I don't think it's clipping because SEG4 never went larger than 19000 counts during RM1/RM2 full scan.

model restarts logged for Wed 17/Sep/2014
2014_09_17 13:14 h1suspr2
2014_09_17 13:14 h1sussr2
2014_09_17 14:47 h1fw0
2014_09_17 18:14 h1sussrm
2014_09_17 22:27 h1fw1

unexpected restarts of h1fw[0,1]. Sus TACQ model changes.

Alexa, Rana, Sheila, Kiwamu,

We locked the DRMI tonight for the first time. It could stay locked for more than 10 minutes.

(A prep: PRMI locking with REFL signals)

Before moving onto the DRMI locking, we wanted to lock the PRMI on the sideband without using the AS detector. We first locked the PRMI with the conventional sensors i.e. REFL9_I for PRCL and ASAIR_45Q for MICH respectively. By exciting and looking at transfer coefficients, we figured out 

REFL45_Q = -12.5 x ASAIR_RF45_Q for MICH readout

So, we put 1/-12.5 = -0.08 in the input matrix and this worked.

Also, the large fluctuation we saw in REFL_A_RF45 yesterday (alog 13968) was visible today as well before we transitioned to REFL_RF45_Q for MICH. We checked if this behavior is also visible in REFLAIR_A_RF45. This was actually visible in REFLAIR_RF45 as well. This incidicates the fluctuation comes from some kind of common place in the REFL path or the ASAIR_A is imposing this fluctuation in the MICH through its feedback. Once we transitioned onto REFL_A, we saw both REFL_A and REFLAIR RF45 signals suppressed. On the other hand, as expected, ASAIR then started wandering.  We should check some clipping or some obvious things on the ASAIR detector tomorrow.

(DRMI lock)

We aligned the SRC by locking SRY with ASAIR_RF45. Also we adjusted the demod phase of ASAIR_B_RF90 such that the signal is maximized in in-phase. At the beginning, we adjusted the demod phase such that the PRMI carrier resonance gave negative values.  This was then flipped by 180 deg after we locked the DRMI because this signal stayed at a negative value when the DRMI was locked.

• REFL_A_RF9_I => PRCL
• REFL_A_RF45_Q => MICH
• REFL_A_RF45_I => SRCL

To lock the DRMI, we reduced the MICH gain by a factor of 5 according to Anamaria's DRMI document, but eventually we ended up with a gain reduction of only a factor of three which resulted in repeatable locking. We did not have to change the PRCL gain from the PRMI locking gains as expected. We guessed the SRCL gain from the same document. We fiddled with the control sign and gain for an hour or so and eventually it started locking.

We coarsely adjusted the PRM and SRM M2 stages to maintain the DRMI lock for a long time. The gains are right now based on some models/guesses. So we will revisit these values tomorrrow.

(SRC hopping ?)

We are not sure what is going on, but the SRC seems to jump back and forth between two modes. It looks as if the hopping is triggered by some slow misalignment. Depending on time, it happened as frequent as once per a couple of seconds. And sometimes it did not happen for some time like 20 seconds or so. This is visible in the dark port camera and AISAIR_RF90 which went back and forth between a high and low values. The low value went to a negative number for some reason. We need to investigate this issue more to figure out what is happening.

Sheila, Rana, Kiwamu, Alexa, Daniel

We had not been able to lock the PRMI all of today. During the day's usual ISI shaking we noticed that the AS beam had gone nearly of the camera and so spent awhile chasing trends, etc.

After not finding the cause of that, we noticed that the AS45 and REFL45 signals had dropped off to nothing around 3AM local time. As far as we can tell, no one was on site at the time.

Afer some hunting, we found a particularly horrible electronics setup for the 45 MHz modulation amplifier in the H1 CDS electronics room on the same rack as the 9 MHz Marconi generator:

There was an unsecured ZHL-1A amplifier on top of the rack, powered by a DC bench supply (of the lowest quality available), and connected by damaged Banana cables. The banana power cables are intermittent and turn off the amplifier power once in awhile. We could see the power supply current vary to any value between 0 and 400 mA as we brushed the cables - I wouldn't trust this amplifier any more.

Several people disavowed any knowledge of this setup (even after we found https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=11986). It contained a few low quality L-Com cables and several cheap BNC barrels. We must never use BNC connections and these kinds of unreliable adapters in our low noise RF setups. Only N and SMA connections are allowed.

We have relocked the PRMI after removing this setup. The modulation voltage for 45 MHz is now 4x lower. It would be best to make a higher quality RF amplifier setup underneath the PSL table as was done at LLO. We'll be using this weaker modulation for another few days, but we want the higher modulation depth by mid next week, when we get back to the 3f locking.

Here's a 1-minute video of a PRMI sideband lock, from the AS port camera.  Kiwamu, Rana, and Sheila will write more about this later in the evening.

Yesterday by the end of the day the main path through to the pericope had been aligned on the X-arm table.  This morning we started with a projection as described in https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=13975.  As part of this we realigned the beam through the mask to optimize the shape on the screen.

Later today we aligned the power meter, and ISS photodiodes.  The QPDs were checked and are stlil aligned.  We calibrated the photodiodes and then started to calibrate the rotation stage for the output power to the CP.  However we found a maximum throughput of only 2.5W.  Clearly  we are losing a lot of power somewhere.

The table has a second IR camera located on the optical table.  Before the adjustment during the projection the beam on this looked quite uniform.  After finding that we were losing power I looked at the image on this camera, which is taken using a 50% splitter mirror from the beam going to the CP.  The image is attached, but appears to show that we are now not well aligned through the mask.  We'll need to redo this alignment, but it is surprising that the image from the projection and the image on the table look so different.  Possibly this is just the lower resolution of the camera used to image the projected beam.

RGA is baking overnight -> The 1.5" gauge pair pump port valve is closed as well as the 10" gate valve -> Leaving PT346B off while unpumped (i.e. while the 10" gate valve and 1.5" valves are closed)

On the BSC-ISIs, things have been running differently at LHO and LLO for quite a while.

I took a look at a random chamber (ITMY) for both sites to see how we can make the best out of both configurations.

LLO ITMY Status:

Stage 1

- X, Y: 45mHz blend, FeedForward from HEPI, Sensor Correction

- Z: 90mHz blend, FeedForward from HEPI, Sensor Correction

- RX, RY: 250 mHz blend

- RZ: 200mHz blend

Stage 2

- X, Y: 250mHz Blend

- Z, RX, RY, RZ: Damping only

LHO ITMY Status:

Stage 1

- X, Y, Z: 45mHz blend

- Z: 90mHz blend

- RX, RY, RZ: 250 mHz blend

Stage 2

- All DOFs: 750mHz Blend

As we can see, the main difference is on Stage 2: most of the DOFs are turned off (damping only) at LLO. On the other hand, they have more features (FeedForward, Sensor Correction) installed on ST1 then at LHO.

By looking at the results, we see pretty similar results in X and Y.  LLO seems to do a little better at 0.5Hz (better blend design, sensor correction). But, by looking at the rotational degrees of freedom, we can see that having a high blend on ST2 at LHO doesn't affect the low frequencies and help a little around 1Hz (we see that also in the optical lever).

In conclusion, turning on the sensor correction at LHO seems to be the next step. At LLO, it seems that turning ON the stage 2 loops with high blend filters wouldn't hurt.

The commissioners have been complaining about too much motion in Yaw on the BS (almost 2microns peak to peak at 10 mHz (!!)).

We know we have some pick up between Z and RZ (see the various SEI logs from the last 6 months), so I switched from a ~100mHz blend in Z to a 750mHz. Relaxing the actuation in Z reduced the pick up seen in RZ.

I was afraid to degrade pitch with this change, but we improved yaw by a factor of ~5 without changing the pitch integrated RMS (it introduced a peak around 1Hz though).

I've tried to implement a 250mHz blend, but no improvement...

Thus, the configuration that seems to satisfy the commissioners is:

- Tbetter: X, Y, RX, RY

-Tcrappy: RZ

- T750: Z

I'll check what is the status of this "pick up" on the other chambers ASAP.

A. Sevingy, J. Kissel, A. Staley

Continuing with the installation of modified triple acquisition drivers into all lower stages of Recycling Cavity HSTSs, as per ECR E1400369, Integration Issue 936, and work permit 4850. Aaron will post serial numbers when the final install of SRM is complete, however, anxious to use the new drivers, Alexa and I followed yesterday's procedure (see LHO aLOG 13958, we started at Step 2) to make the necessary software changes to support the new drivers on H1SUSPR2 and H1SUSSR2. The only difference was that, unlike PRM, the "twos" needed BOTH stages of COILOUTF filters modified, since they did not have a prior modified driver installed in M2.

new safe.snaps, filter files, and top-level models have been committed to the userapps repo. As with yesterday's changes, no DAQ restart was required.