J. Kissel, J. Warner

Since we're running out of time before we re-open the arms, I offered a few of my computational cycles to gather some of the very-low-frequency transfer functions Jim's been trying to get over the past few days. 

For the full story of what these transfer functions are and why they're needed, follow along in LHO aLOG 1158. 
In summary, the SEI team has found excess low-frequency ST1 Z to X and Y coupling that has coherence with DARM below a few 100 mHz.
    - Krishna surmises that small generator constant / gain mismatch in a given ISIs T240s in the Z direction means 
      that some fraction (at the 0.5% level) of the physical Z motion is getting translated into Tilt (RX and RY). 
    - Because the ambient/physical RX/RY motion is much smaller than the abmient/physical Z motion (by a factor of 
      50-200), then the Z * 0.5% appears to dominate the RX / RY signal at low frequency.
    - This excess errant tilt then couples via the usual g/w^2 into X and Y, pushing the platform errantly in the 
      IFO's beam direction, coupling into DARM. 
    - However, after some initial data analysis, they found that low frequency RX / RY motion is dominated by Z to 
      RX / RY capacitive position sensor misalignment in the ISI.
So, these measurements serve to characterize this CPS misalignment, such that it can be corrected for and *then* we can get down to the T240 Z > RX/RY > X/Y coupling that Krishna suggests.
#it'salwaystilthorizontalcoupling

The first coefficient Jim has been able to calculate during this vent -- the ETMX Z to RX/RY coefficient = -0.0025 (H1:ISI-ETMX_ST1_CPSALIGN_6_4; which Jim admits is an eyeball of Rich's processing of his previous measurement in SEI aLOG 1170). He's shown me some preliminary, as-yet unpublished, data that suggests a reduction of a factor 5-10 (if memory serves), essentially eliminating the CPS misalignment effects. Good! 

So, I gather more CPS plant characterization measurements for him so he can do it on every chamber.

The configuration of any given platform during the measurement:
    - CPS dominated, high-frequency blend filters ("Imp_Hi_Blend") on all DOFs for ST1
    - 250mHz,ellip blend filters on ST2 for X, Y, Z, RZ (RX/RY are never isolated)
    - Platform isolated as normal (ETMs / ITMs: fully isolated, BS: ST1 Isolated/ ST2 Damped.)
    - No sensor correction (neither HEPI Z or ISI X/Y)
    - Standard high frequency HEPI L4C ST0 to ST1 FF in all DOFs
    - Standard ST1 L4C/T240 blend FF to ST2 in Z (on ETMs / ITMs, not for isolated/damped BS)
Note, in order to switch *to* the "Imp_Hi_Blend" filters, you must turn off the isolation filters, switch the blends, then re-isolate. Returning from these blends to nominal, you can switch on the fly with the isolation loops closed.

The drive -- using awggui, run the following excitation: 
    - 0.001 - 1 Hz Uniform excitation in the desired DOF's ISO bank EXC (e.g. H1:ISI-ETMX_ST1_ISO_RX_EXC)
    - Amplitude of 1 (no offset, not phase)
    - with a fancy-pants band-pass: zpk([0;0;0;0],
                                        [-0.00155743+i*0.0125715;
                                         -0.00155743-i*0.0125715;
                                         -0.0106671+i*0.0201531;
                                         -0.0106671-i*0.0201531;
                                         -0.0485981+i*0.0918139;
                                         -0.0485981-i*0.0918139],
                                        0.0068)
    - Phase In/Out = 20 sec
    - Gain = 1e5 for RX/RY, 2e7 for Z
    - Ramp Time = 20 sec
For as long as you'd like to get enough averages and/or for how much time you have time. I attach a screenshot of an example awggui session.

Here's a table of the measurements I was able to get this evening.
    Start       01:15 UTC    02:15 UTC    03:30 UTC    (All times in the UTC morning of May 24 2017, or PDT evening of May 23 2017)
    End         02:10 UTC    03:10 UTC    04:25 UTC      
    Duration    00:55 min    0:55 min     00:55 min   
    
    ETMX        RX (1e5)     Z  (2e7)
    ETMY        RX (1e5)     RY (1e5)
    BS                       Z  (2e7)     RX (1e5)   

Notes for Jim / Data Analysts: 
    - There's a few minutes padding around all the times while the platform was in the excited configuration, so you may be able to squeak a few more averages out of the data if you're desperate. 
    - The ISI BS watchdog tripped as I was ramping off the Z excitation -- did it too quickly; that's why it took me longer to get on to the next RX/RY DOF.
    - Low frequency ground motion has noticable amounts of wind excitation over the entire duration of these measurements; not sure if it impacts the measurement at all, but I figured I'd mention it since that's the frequency region in which you're characterizing the CPS.
    - Sorry -- didn't get ISI BS RY, wanted to go home. 

Once measurements were complete, I've restored the platforms to their nominal O2 configuration (as per G1700245):
    - Quite_250, 250 mHz blend filters on ST1 in X Y RX, RY, RZ, with Quite_90, 90 mHz blends on ST1 Z
    - 250mHz,ellip blend filters on ST2 for X, Y, Z, RZ (RX/RY are never isolated)
    - Platform isolated as normal (ETMs / ITMs: fully isolated, BS: ST1 Isolated/ ST2 Damped.)
    - ISI X/Y broadband sensor correction, with assistance from beam-direction BRS where applicable
    - Standard high frequency HEPI L4C ST0 to ST1 FF in all DOFs
    - Standard ST1 L4C/T240 blend FF to ST2 in Z (on ETMs / ITMs, not for isolated/damped BS)

[Jenne,Sheila,Vaishali]

Today we tried to fix the IMC Trans in air path that we only use for triggering purposes. Having known what the beam on the MC2 Trans camera used to look like we wondered why we weren"t able to increase the power on the IMC-TRANS PD and tried recover that by doing the following things:

1.Turn up the laser power to 30 W to be able to see the beam (The beam was quite dull at 30 W thus explaining why we couldn't see anything on the viewer card at 2 W)

2.Then we tried to maximise the power on the IMC Trans PD and since the image and the power didn''t get any better we went onto step 2

3.We re-aligned the entire IMC Trans Path in air optic to optic starting from the Bottom periscope mirror -2" steering optic-second steering mirror-Beam splitter- the PD at first. We then maximised the signal on the PD.

4.Being satisfied with the alignment till the beam splitter,we realigned the beam into the camera and it doesn't look great but atleast we see something now.

A little improvement has been made overall but the total power on the PD is lower than before the vent. 

Attached are the images of the "new" normal at both 2 W and 30W as the file names suggest.

Preparations to open the Corner Station to the beam tubes has resumed at the request of the various interested parties and confirmed by Keita.  

I reduced the Vertex RGA's filament emission current to 1ma down from 2ma (done earlier today).  Next, I energized IP1.  Recall that its isolation valve had leaked when the Vertex was vented.  We had de-energized this ion pump as soon as we realized that it was at high pressure on the day of the Vertex vent.  Later during the early portion of the pump down, it was valved-in to the Vertex volume but left de-energized until this evening.  Attached is the pressure response data due to energizing this 2200 L/s ion pump while exposed to the Vertex+YBM+XBM volume.  Three turbos, for a combined N2 pump speed of ~6000 L/s were pumping at the time.  It doesn't come accross in the graph, but I noticed that PT120, PT170 and PT180 were in excellent agreement when the pressure was briefly around 1 x 10-6 torr.  This is interesting to us for reasons to burdensome to describe here.

After it became obvious things were behaving as expected, I valved-in the 5 other 2200 L/s ion pumps.  This was followed by valving-out the (3) turbos.  Things look normal at this point so I am going home.  Tomorrow, I'll start off by taking an RGA scan, dumping GV5 and GV7's unpumped gate annulus volumes into the adjacent annulus volumes (I haven't forgot Chandrohn, I just haven't had the chance to start the new policy) and then opening GV5 and GV7.

J. Kissel

I've taken the time to export all of the 2017 data from H1 SUS ITMX so I could compare it all and against 2014 data, data other ITMs, and the QUAD model. In short: The data looks consistent with the model, and with all other ITMs. Nice!

I attach 4 sets of plots in support of this, 2 for each chain.
Main Chain (M0): 
    (1) "H1SUSITMX_Phase3 ... ALLM0" This shows the progression of H1 ITMX M0 from the 2014 acceptance measurement to the three measurements from this year, all compared against the QUAD model. For reference I also include L1 ITMY. No major deviations from the model or each measurement. The largest outlier appears to be the 2017-01-17_2134 measurement, but these "extra" resonances are cross-coupling from other degrees of freedom's previous transfer function. For example, the 2017-01-17_2134 Roll measurement contains a good bit of the 0.55 Hz vertical mode, because the Roll measurement was started too quickly after the Vertical measurement, without damping the SUS in between. In the latest measurement (2017-05-22_2056) I took the time and damped the SUS between each DOF's measurement, and et voila! No V resonances in your R measurement.

    (2) "AllITMs_Phase3 ... ALLM0" This shows the latest H1 SUS ITMX measurement against every other ITM main chain. This shows that ITMX is remarkably consistent.

Reaction Chain (R0):
    (3) "H1SUSITMs_Phase3 ... ALLR0" The shows the progression of ITMX R0 from the 2014 measurement to the three 2017 measurements, all compared against the model and L1 ITMY. It is here -- specifically in the Pitch direction that we're reminded that the transfer function looks nothing like the model, but it's because of the cabling down the reaction chain that's not included in the model. The only other mildly suspicious feature is the changes in Q of the 2nd, 0.8 Hz Longitudinal mode, but I think this again depends on how excited these modes are before the measurement, and there's some mixing between the 0.79 Hz Pitch mode -- unpredicted by the model because of the cabling.

    (4) "AllITMs_Phase3 ... AllR0" This comparison is the best reminder that the Pitch TF is a function of the cabling on the reaction chain. The fifth page shows the nice rainbow of the 2nd pitch mode (modelled to be 1.34 Hz) across the various builds of the suspension throughout the project.

So -- other than its alignment, I think this SUS is ready for an IFO.

One more thing to note: since there is little to no difference between the 2017-05-16_2345 and 2017-05-23_0047 measurements, this would argue that we no longer need the 150000 V or -5000 P offsets from a rubbing stand point. Perhaps we can assess and explore removing them once we get back to a comfortable BNS sensitivity.

Dave and I had been discussing https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=36294.  One solution we thought about was just disabling the optimization that gave us bad data.  The thinking was that when it was put in we used 1 minute second trend frames.  It would be faster to open one 10 minute second trend frame than ten 1 minute trend frames.  I wanted to characterize the impact of the shared table of contents optimization.

My thoughts on this are:

1. Getting correct data from nds1 is important, restarting the daq should not be a reason to give bad data (even if it is only for a few minutes).

2. We should preserve the table of contents optimization, it does have some impact.

All timings are from my laptop connecting to the LHO DTS x1nds1 server via an ssh tunnel.  It should be noted there were several restarts of the nds/fw/dc on the DTS during this time window, so the penalty of not being able to share the table of contents is high in these short samples.  I ran the queries below multiple times to make sure the disk cache was hot and picked a representative time for each case.

The measurements:

Quick query against x1nds1 with the current production code (no changes)

$ time nds_query -d 400 -n localhost -p 8088 -s 1179600000 -e 1179603000 X1:DAQ-DC0_DATA_RATE.mean,s-trend
Data for 600 seconds starting at GPS: 1179600000
Channel                                  type      nWords   units
X1:DAQ-DC0_DATA_RATE.mean                real_8       600 
Data for 600 seconds starting at GPS: 1179600600
Channel                                  type      nWords   units
X1:DAQ-DC0_DATA_RATE.mean                real_8       600 
Data for 600 seconds starting at GPS: 1179601200
Channel                                  type      nWords   units
X1:DAQ-DC0_DATA_RATE.mean                real_8       600 
Data for 600 seconds starting at GPS: 1179601800
Channel                                  type      nWords   units
X1:DAQ-DC0_DATA_RATE.mean                real_8       600 
Data for 600 seconds starting at GPS: 1179602400
Channel                                  type      nWords   units
X1:DAQ-DC0_DATA_RATE.mean                real_8       600 

real    0m0.723s
user    0m0.008s
sys    0m0.000s

Quick query against x1nds1 with the frame table of contents optimization disabled.

$ time nds_query -d 400 -n localhost -p 8088 -s 1179600000 -e 1179603000 X1:DAQ-DC0_DATA_RATE.mean,s-trend
Data for 600 seconds starting at GPS: 1179600000
Channel                                  type      nWords   units
X1:DAQ-DC0_DATA_RATE.mean                real_8       600 
Data for 600 seconds starting at GPS: 1179600600
Channel                                  type      nWords   units
X1:DAQ-DC0_DATA_RATE.mean                real_8       600 
Data for 600 seconds starting at GPS: 1179601200
Channel                                  type      nWords   units
X1:DAQ-DC0_DATA_RATE.mean                real_8       600 
Data for 600 seconds starting at GPS: 1179601800
Channel                                  type      nWords   units
X1:DAQ-DC0_DATA_RATE.mean                real_8       600 
Data for 600 seconds starting at GPS: 1179602400
Channel                                  type      nWords   units
X1:DAQ-DC0_DATA_RATE.mean                real_8       600 

real    0m2.077s
user    0m0.000s
sys    0m0.008s

Quick query against x1nds1 with using the table of contents optimization with some additional knowledge of fw restart times.  This is were we need to be, always correct, but able to use some frame access optimizations.  This can be improved by taking into account which restarts are also channel list changes, and which are just restarts.

$ time nds_query -d 400 -n localhost -p 8088 -s 1179600000 -e 1179603000 X1:DAQ-DC0_DATA_RATE.mean,s-trend
Data for 600 seconds starting at GPS: 1179600000
Channel                                  type      nWords   units
X1:DAQ-DC0_DATA_RATE.mean                real_8       600 
Data for 600 seconds starting at GPS: 1179600600
Channel                                  type      nWords   units
X1:DAQ-DC0_DATA_RATE.mean                real_8       600 
Data for 600 seconds starting at GPS: 1179601200
Channel                                  type      nWords   units
X1:DAQ-DC0_DATA_RATE.mean                real_8       600 
Data for 600 seconds starting at GPS: 1179601800
Channel                                  type      nWords   units
X1:DAQ-DC0_DATA_RATE.mean                real_8       600 
Data for 600 seconds starting at GPS: 1179602400
Channel                                  type      nWords   units
X1:DAQ-DC0_DATA_RATE.mean                real_8       600 

real    0m1.595s
user    0m0.004s
sys    0m0.004s
 

Daniel, Kiwamu per WP6650,

We made two major changes to IOO today as follows.

• The IMC locking RFPD (36322) was replaced by the one with the correct resonant frequency.
• A new modulation path for 118 MHz was added to the existing 24 MHz modulation path via a power combiner.

After these tasks, we have confirmed that the IMC could still lock with an UGF of 50 kHz (which had been 54-ish kHz before we made changes today, approximately corresponding to a 1 dB loss in the sensing system). Tomorrow, we will try to measure the modulation index for 118 MHz using the Michelson fringes.

[IMC length RFPD]

The old unit (S1203263) was replaced by the one with the correct resonant circuit (S1203775). I have repeated the same measurement as yesterday with the AM laser (36322) to check out the response of the new RFPD. The first attached figure shows comparison of the new and old RFPD responses. The magnitude at 24 MHz was found to be lower than that with the old one by half a dB. So the response is virtually unchanged at 24 MHz. The raw data is attached as well.

I made sure about the alignment of the beam onto the RFPD by touching the 2" steering mirror in front of it. I also made sure that the reflection from the RFPD was dumped properly with a razor blade.

[Addition of 118 MHz modulation]

We newly installed two IFR function generators in an ISC rack in the CER. One of them provide us with the modulation rf source at 118 MHz while the other does for the demodulation at 72 MHz or whatever frequency we desire. The 118 MHz generator was then hooked up to an RF amplifier, ZHL-1-2W, and then to the patch panel which transfers it to the ISC field racks by the PSL. Then, the 118 MHz signals is combined with the existing 24 MHz modulation signal via a power combiner, MECA 2-way combiner. As it turned out that the power combiner gave us a relatively high insertion loss of ~3 dB, we decided to increase the rf power for 24 MHz as a compensation. We increased it by installing another MECA 2-way combiner and let it do the coherent sum. So in total we have installed two 2-way combiner in series as seen in the attached picture.

We also studied rf losses for 118 MHz and found extra frequency dependent losses in the cable that connects the field and remote racks. The cable loss for 118 MHz was found to be higher than that for 24 MHz by a couple of dB. In the end, we measured an rf power of 30 dBm for 118 MHz at the output of the last power combiner, which we think is reasonably high and not too high for causing serious problems with the EOM. Note that we tried inserting a balun which turned out to be as lossy as 3-4 dB. So we decided not to use a balun for 118 MHz. We are thinking of installing a DC block instead.

As this setup messed up the rf phase, we then re-adjusted the delay of the delay line unit for 24 MHz, by flipping 1 and 2 nsec switches. This gave us almost the same UGF of 50 kHz when the IMC was locked with a 2 W input and with the new RFPD in use. Good.

TITLE: 05/23 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: Busy maintenance day. There were a large amount of card reader alarms today, please make sure that you are using your card and informing the operator of your work.
LOG:

• 15:03 Peter to LVEA to check for PSL water leaks
• 15:10 Peter out, leak found
• 15:29 Corey to MY for inventory
• 15:46 Cintas in at the gate
• 15:49 Coca-Cola at the gate
• 16:01 Christina to EX
• 16:03 Jeff B to LVEA to fix leak
• 16:25 Kyle taking forklift to MX
• 16:27 Fil and Gerardo to EY to start WP6646
• 16:41 Norco truck at gate, going to EY (71)
• 16:45? Daniel in LVEA at some point
• 16:56 Daniel out
• 17:04 Jeff B and Peter out
• 17:12 Travis to EX for PCal measurement
• 17:26 Jeff B back to LVEA to check on leak
• 17:37 Kiwamu to LVEA at IOT2 to replace RFPD
• 17:42 Norco at the gate headed to MY (74)
• 17:47 Jeff B out
• 17:48 Karen back from EY, heading into the LVEA
• 18:20 Travis back, Kyle back
• 18:28 Gerardo and Fil back
• 18:39 Paradise water at gate
• 18:47 Marc to MY
• 19:04 Marc back from MY
• 19:08 Karen out
• 19:10 Jeff B and Peter to LVEA for leak
• 19:21 Jeff B and Peter out
• 19:41 Corey back
• 19:57 Fil to EX for WP 6646
• 20:26 Kiwamu and Daniel to LVEA working on IMC
• 20:36 Kyle to LVEA for WP6653
• 20:42 Travis back
• 20:52 Hugh to EY after stopping at a mid station
• 20:54 Richard to LVEA
• 22:06 Bubba to EX mech room
• 15:10 Gerardo to EY to continue BRS work
• 22:16 Kiwamu and Daniel out

Today the fluid level in the HEPI system was down by 7/16" since I last looked on 10 May.  That is the day Jim and I did the accumulator charge check.  I checked the runs and could find no trace of fluid outside the system.  None in the relief or overfill lines at the reservoir.  I suspect that one or more of the accumulators that were checked on the 10th started leaking when we left them.

I'd like to check the charge again asap, certainly before going back to full IFO ops.  This requires the SEI to be completely off-line so the HEPI Pump can be stopped.  Look for a WP 6655.

FRS8180

Due to the rising outside temperatures, the exhaust line thermocouples are experiencing temperatures exceeding 40C, taking them off the top of the robo-striptool plots.

I have increased the Y max from 40C to 60C. Attached plot shows CP4's signal at 45C is now visible.

WP 6577

Migrated end X FMCS channels to BACNet IOC. Burtrestored to 6 AM this morning (local time).

   Found a pair of launderable shoe covers in the trash. 

   When finished wearing launderable shoe covers please put them in the basket marked "Dirty Shoe Covers". The disposable shoe covers should be thrown out when you are finished using them. 

  The disposable shoe covers are found in a tote labeled "Disposable Shoe Covers". They are made of a light solid white reinforced paper like material. The launderable show covers have a brown semi hard sole and C3 uppers. The launderable shoe covers cost between $20.00 and $35.00 each, and take 6 to 8 weeks to put into service.

   Please let me know if you have any questions.  

  

model restarts logged for Mon 22/May/2017 - Fri 19/May/2017 No restarts reported

model restarts logged for Thu 18/May/2017
2017_05_18 12:07 h1broadcast0
2017_05_18 12:07 h1dc0
2017_05_18 12:07 h1fw0
2017_05_18 12:07 h1fw2
2017_05_18 12:07 h1nds0
2017_05_18 12:07 h1nds1
2017_05_18 12:07 h1tw1
2017_05_18 12:09 h1fw1

Maintenance Thursday, DAQ restart for vacuum controls IP6 change.

model restarts logged for Wed 17/May/2017 - Tue 16/May/2017 No restarts reported

model restarts logged for Mon 15/May/2017
2017_05_15 11:25 h1nds1

Unplanned restart of default NDS due to problems possibly caused by new client code.

J. Kissel, J. Warner

H1 ISI ITMX ST2 (not ST1 or HEPI) tripped last night at ~9:30 UTC (1179548979, May 23 2017 04:29:21 UTC, May 22 2017 21:29:21 PDT) because Jeff forgot to turn the Reaction Chain damping back on after completing its set of transfer functions (LHO aLOG 36335). 

In order to help non-Jeffs diagnose the issue, Jeff has moved the link to the reaction chain on the QUAD overview screens,
    /opt/rtcds/userapps/release/sus/common/medm/quad/
        SUS_CUST_QUAD_OVERVIEW.adl
        SUS_CUST_QUAD_ITM_OVERVIEW.adl
to the top center (essentially swapping the positions of the never-used hierarchy switch and the reaction chain screen link). I've also added inputs and outputs to the R0 damping loops surround the button to remind people that there's a control system there which occasionally needs attention.

The screens have been committed to the userapps repo.

P.S. This interaction between a full isolated ISI and an undamped chain of the QUAD is not new, it's just been a while since we've regularly taken the full suite of undamped TFs on any QUAD, and I've forgotten that one should put the ISI ST2 in DAMPED. And also I haven't used the matlab automated transfer function suite that does all the settings in so long that I fear it'll do more damage than good. In the limit of infinite IFO time and person power (e.g. between O2 and O3?) we'll resurrect that code.

We have identified the source of a comb with a fundamental frequency of 11.111 Hz that appears in the DARM channel and also in the PEM magnetometer channels. 
 
The noise source appears to be a particular pressure sensor with the frequency given by the communication with the Beckhoff computer. We measured the magnetic spectrum at BPG402-SE pressure sensors both in the EY station and in the EE shop, and we saw the 11.111 Hz comb that we were looking for (see the attached plot for a spectrum). The frequency measured in the EE shop was either 11.111, when there was one PLC task cycle time of 10 ms, or 11.9 when Patrick set up two tasks with settings of 1 and 10 ms. Using a strobe light, we found that the LED on the pressure sensor also blinked at 11.1 or 11.9 Hz.  As expected from the settings, the Beckhoffs in most of the racks at EY produced an 11.9 Hz signal (detected by magnetometers on the slow controls boxes, but not seen in DARM), while the one in the vacuum rack produced the 11.111 Hz signal.
 
The coupling to DARM is likely happening because the pressure sensor used in the ESD pressure interlock is sharing the power supply with the electrostatic drive. The 24 V power cable to the ESD was a strong source of 11.111 Hz magnetic fields.
 
The solution to this problem may be changing the power supply of the pressure sensor. This work will be done this week, and we will be able to test if the comb goes away when the detector is back and we can get spectra of the DARM channel.
 
Pep Covas, Robert Schofield, Patrick Thomas, Richard McCarthy

looks like CER activity possibly caused a timing glitch on h1seih23. I restarted all the models, no need for reboots or power cycles.

In the past couple of days, somewhat more than the usual amount of water required to top off the chiller has been added.
This morning I added ~200 ml.  Yesterday JeffB added a similar amount.

    I took a look under where the air trap was installed last week and sure enough there are some drops hanging onto
the pipes and a wet spot on the floor underneath.

[Vaishali, Jenne]

We went again to have a look at the IMC trans path on IOT2L, and we think that the main beam is just not coming out of the vacuum.

Kiwamu pointed us to alog 17310 from March 2015, where he notes that something happened in vacuum and the IMC trans beam went from somewhat clipped but still somewhat normal looking to totally abnormal looking (which we've had consistently for the last 2 years).  Vaishali is currently looking into Cheryl's IMC spot measurements to see if the beam spot motion is consistent with the beam moving closer to a position where the trans beam is clipped on the IM1 suspension cage.

We still have the ghost beam on the trans camera, but no beam bright enough (by a factor of ~100, as measured by the PD) to be the main beam.

Nothing unusual to report.