I have installed a new EPICS IOC (dac_overflow_rate_ioc) which for each model calculates the per second increase in the accumulated DAC overflow counter. If the rate is non-zero, the upper block of the DAC Overflow square in the CDS Overview turns yellow. The lower block shows dark green if the accumulated counter is non-zero (i.e. overflows in the past which have not been cleared).

The new IOC runs on the service host cluster, it is monitored by a "DAC OVERFLOW" system block at the bottom of the CDS Overview.

Please note that the accumulated DAC overflows wrap-around at 0x1000000 (just over 16 million) to prevent the number on the MEDM becoming too large to be read.

Jennie W, Sina K, Jim W,

We made good progress today. There was a factor of 4 that we had forgotten in the demodulation that you need to scale the final amplitude by to get the Vpp. Once we put this in we get ~100% for the reference interferometer and 76% for the measurement interferometer.

We debugged the demodulation calculation by turning off the signal input to the REF A IFO and then looking at what heterodyne amplitude it calculated when we injected a signal of 2Vpp into the H1:SPI-H23_IFO_REF_A_DEMOD_SIG filter bank.

See the photo showing the injected signal calibrated into volts in yellow, in purple the amplitude calculated as A = sqrt( I^2 + Q^2), where I and Q are the output of the demodulator, and in red is the out amplitude after multiplying by a factor of 4.

I put this calibration factor into all four H1:SPI-H23_IFO_{REF,MEAS}_{A,B}_HETAMP filter banks as cal_demod in FM0.

We also measured the dark offsets for the four PDs and two QPDs. We did this with the shutter closed. From the input counts, the QPD B segments look a lot noisier than the QPD A segments so I wonder if we are getting scattered light from main IFO beam.

I might redo this dark offset test with the JAC unlocked or with the PSL shuttered in order to verify this. It might also explain why we occasionally get the efficiency calculation of the reference interferometer coming out to 101% if we have stray light on one or more PDs.

The calibration factors and new dark offsets were accpted in SDF.

One of the nights this week we will start our program of calibration measurements using the ISI sensors to calibrate the SPI sensors.

Per WP 13415 I finished migrating the dust monitors and the dewpoint monitor to the IOC cluster (service-host 0,1,2).  With this I was able to turn off the old h0epics server.  These will now auto start after power outages as well as there are no manual steps in the startup sequence.

One note.

The dewpoint monitor held its files in /ligo/lho/h0/target.  As a limit in the container I am running these in it wants the command that is executed to be under /opt/rtcds.  So I copied the target area over to /opt/rtcds/lho/h1/target and put a symlink in on /ligo/lho/h0/target/dewpoint.

TJ, Camilla WP #13528

Today we swapped the ITMY HWS SLED as it had degraded, last swapped May 2025 84417.

Following the T1500193 procedure

• Starting:
  • ITMY SLED removed - https://ics.ligo-la.caltech.edu/JIRA/browse/QSDM-840-5-0-00-06.18.005 
• Ending:
  • ITMY SLED installed: https://ics.ligo-la.caltech.edu/JIRA/browse/QSDM-840-5--00-09.23.313 2.5mW = 90mA = 360mV (on TP with 250mA/V) Max current set to 85mA
  • Power as measured from fiber launcher: IX 1.4mW, IY 1.6mW 

TITLE: 08/17 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: Ryan C
SHIFT SUMMARY: After diagnosing some alignment troubles, work has continued towards being able to lock PRMI. The ITMY HWS SLED was swapped, the corner volumes continue to be pumped down, and the LVEA is still Laser HAZARD.
LOG:

[Huyen, Shoshana]

We saw worsening CRS noise after adding copper block on top of the laser in an attempted to help with thermal regulation. We went ahead and removed the copper block and saw that the noise improved significantly.

Picture one shows the noise taken over the weekend with copper block on the laser (with capacitive damping on) [ref], and the noise during the day right after the block was removed (with capacitive damping on).

When removing the copper we noticed it was pretty cool to the touch, so it probably wasn't providing much thermal regulation to begin with (i.e. the TEC is doing it's job). Our best guess for why it was worsening the noise is that having some extra weight on the laser was adding some extra stress onto it which was translating to the signal.

Since getting the capacitive damping hooked up, we've been keeping the gain at 100, which seems to damp down the CRS at a reasonable rate without putting to much voltage on it, and we decrease the gain to 50 once the  CRS is relatively damped down. 

We've been having some confusion in the control room this morning on the IFO alignment as we've been struggling to lock PRMI despite running the usual initial alignment steps successfully and with it having been locked last week. While trending things from last week to see what may have changed, Louis discovered that around 05:45 local time last Monday morning (August 10th), the alignments for the IMs changed notably according to their OSEM readbacks. This lines up with an earthquake that came through at that same time, which tripped the ISI platforms in HAMs 1-5 (noted in the operator shift start alog). It's been seen in the past that a HAM2 ISI trip has caused the IMs to move, so unfortunately this isn't surprising. Also unfortunately, the alignments for the IMs were not restored, so the alignment work that took place later that day to prepare for the peek down the X-arm (alogs 91463 and 91470) would have been done with the assumption the input IFO pointing was good, while in reality it was not.

I have restored the alignments of IMs 1-3 according to their OSEM readbacks before the ISI trip, and Louis confirmed the alignment to the IM4 TRANS and ISS secondloop PDs are good. We will continue to recover alignment in the corner to work towards DRMI locking again.

JAC length dither line at 809Hz is on. I also editted the Guardian so that he won't disable it.

It will keep engaged for a couple of days.

TITLE: 08/17 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 5mph Gusts, 3mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.08 μm/s 
QUICK SUMMARY: With all chambers now closed and pumpdown ongoing, the focus this week will be continuing corner alignment and improving DRMI locking. The IMC is locked at 2W and the LVEA is Laser SAFE.

All four JAC pico axes (heads A and B, X and Y motors) have been calibrated in counts to beam displacement on the WFS, by non-locked sweeps read through the WFS DC signals. Efficiencies come out at 0.6–1.2e-3 beam radii per count (0.09–0.19 μm, 0.8–1.6 μrad of beam pointing), with a direction dependence of 9–27 %.

Setup

• 2 W input. Cavity intentionally unlocked before the measurement; each pico was first moved to bring its WFS DC readings near zero (beam near the QPD center).
• Each pico axis is swept at 1 count/s, 200 counts per leg, out and back, so the calibration includes the direction dependence (hysteresis) of the motor.
• Signal: SUM-normalized WFS DC. With the cavity unlocked the beam is a clean Gaussian, so the normalized quadrant signal gives the beam displacement in units of the beam radius directly. The efficiency is fitted per leg.

Conversion

The fit gives the efficiency in beam radii (d/w) per count. Beam radii at the QPDs from the JAC reflected-path optical model:

Results

Denominator: SYS-MOTION_C_PICO_D_CURRENT_X/Y_POSITION [counts] of the swept motor. "up" / "down" refer to the sign of the count sweep.

Attachments: per-axis sweep figures (normalized signal against pico counts).

Miranda, Dave:

Friday afternoon we updated the cable labeling for the ACC BNC coax cables at EX, MX and MY. EY cables were already complete.

At EX we reconnected the BNC for H1:PEM-EX_ACC_OPLEV_ETMX_Y_DQ which we had found to be disconnected. Plot shows it had a signal until the 23rd June of this year.

(Travis, Gerardo)
The ion pump for HAM1 was incorporated to the HAM volume yesterday, and today the SS-500 pump cart was isolated from the chamber (turbo pump and SS-500 remain on), and as expected the pressure went up and now we are waiting for the ion pump to take over and maintain the vacuum pressure for HAM1.  We will be monitoring the progress of the ion pump.

(Travis, Gerardo)
We removed the old gauge a BCG-450 and installed a new one a BPG-552.  Since the gauge at this location does not play role with relays and such, the old pigtail did just fine, provided the power to the new gauge.  The new gauge is powered on and connected to the same EtherCAT cable as the one that that we removed.  Dead volume of this assembly is getting pumped down with a small can turbo pump and an aux-cart, and a very long flex hose, and probably will continue to pump over the weekend.
No issues were encountered while replacing the gauge.

(Travis, Gerardo)
This morning we checked HAM7 annulus system pumpdown and the aux-cart displayed 2.6X10^-05 Torr, good progress so it appears to be doing good.  We disconnected the SS-500 cart from HAM6 turbo and connected it to HAM7.  We checked all ports were "nominal", detached the active purge hose and no blowdown was done, since we had the relay tube valve (RV-2) open, took advantage of this and we let the purge air purge HAM7 overnight out RV-2.  After closing RV-2 we started the pumpdown of HAM7.  The purge valve (all metal valve) and the roughing valve at the turbo assembly were closed at 3.0X10^-05 Torr.
Attached is a plot of the pumpdown thus far.

Jennie W,

Since Daniel put in a TEC controller for the JAC temperature servo we will no longer use the current version of the guardian control loop so I have set JAC_HEATER guardian to SERVO_OFF. The TEC is turned on and the set point is at 25.4 Degrees C.

The servo controller can be reached by going to sitemap->IOO->JAC Overview->Controller. To turn it off select the 'OFF' button in the top right corner of the controller. The loop can be measured by using the excitation button noted in the picture.

I will trial this over the weekend so I can double check it doesn't drive the JAC away from the control point.

Camilla, Oli, Caroline, Masayuki, Sheila

• Before starting the arm peak Masayuki and I aligned PRX and MICH based on the alignment that Louis aloged in 91463  We are seeing flashes of up to 150 coutns on LSC POP A, 130 counts on the ASC POP QPDs, and nothing in POPAIR.  (1st screenshot)
• Once the gate was opened we ran the TMS to ITM baffle PD script without issue.  Caroline and Oli searched for the ETM baffle PD using an awg, and found it, then were able to run the baffle PD script for ITMX.  (2nd screenshot)  This ITMX pitch is different by 50urad.  
• We moved PR3 back to it's O4c alignment, Masayuki and Sheila went to ISCT1 to look for single pass green beam.  We saw it but very low in pitch, adjusted PR3 alignment to put it on the ALS X camera and trans PD.
• Camilla, Oli and Caroline tried to align ETMX using the baffle PD script, but this didn't work well. Once the table was aligned the switched to rastering the ETM and watching for flashes in the camera and trans diode.  
• Just as they were starting to see the flashes, the site power glitched and the HEPI pump controllers went down.  Jim went to EX to bring it back.
• Meanwhile, 10W single bounce off ITMX Masayuki moved IM4 to center the beam on POP X, and PR2 to bring the ITMX reflection onto the REFL PDs and refl camera.  After that worked he aligned PRM to get PRX flashes, then aligned BS for mich fgringes. 
• The single bounce beam looked clipped when SR2 was adjusted to center on the AS camera and AS_C, although the power on AS_C seems correct (0.02W into HAM6 with 9W on IM4).  When we moved SR2 to being the beam high on the camera and QPDs it looked like a normal shape.  Masayuki walked BS and SR2 to try to correct this.  
• Once HEPI was recovered we found the arm flashes in green and locked.  We could not engage slow feedback to the ETM but requested LOCKING from the guardian.  
• Camilla and Sheila aligned the COMM beatnote on ISCT1, and slightly adjusted PR3 pointing to avoid clipping on the path to the beatnote BS.  We got a beatnote of 0dBm, but we can see that the beam is slightly clipped on the prism.  
• Masayuki aligned IM4 and PR2 to get IR aliged to the X arm.  He was able to lock it with a normalized power of 0.95 (close to the nomial 1).
• Masayuki aligned PRM using PRX, and BS using MICH. 
• Sheila and Masayuki went to ISCT1, moved the POP top periscope mirror closer to REFL and down.  We should move the whole periscope over towards refl soon, to center on the pop top periscope mirror.  Then we aligned the rest of the path through to the POPAIR B diode, we see 120 counts on RF18.  
• Masayuki double checked the beatnote, it is -1dBm.  (final screenshot)

TITLE: 08/11 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 9mph Gusts, 4mph 3min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.06 μm/s 
QUICK SUMMARY:

• A few CDS tasks on the docket for today
• CRS work as well
• Optics lab and EX dust alarms
• The AQI is decent this morning at good/28, but it's predicted to worsen to moderate