FAMIS6542
I added 75mL of water to the crystal chiller. It looks like others have been keeping an eye on it and adding frequently.
FAMIS6917
For what its worth while we are vented, here are the spectra. HAM3 H2 is reporting high noise.
Yesterday, starting work on the HEPI Corner Station Filter change, WP 7169, we observed an interesting behavior of the BSC2 Pressure sensors on the supply lines to the LVEA HEPIs at BSC2. When the large ball valves up on the mezzanine were changed to put the system local to the Pump Stations into recirculation mode, the BSC2 pressures started climbing. At the same time, the pump stations were started to recirc the fluid rapidily to get turbulent flow in an effort to clean out the reservoir. This confused us as the BSC2 sensors are valved out so should have no knowledge of what the pump stations are doing.
Ultimately we decided it must have something to do with the head the plumbing has wrt the BSC2 pressure sensors but those numbers don't really yet make sense. Meanwhile, the pump stations were shut down over night, and as you'll see on the attached trends, you'll see that the pressures at BSC2 began falling back to zero but not until hours after the PSs were back to zero. Very interesting/confusing.
I'll restart the recirc op this morning and we'll see what happens. Could the $xxx 1-1/2" swloc ball valves be leaking...
We have way more expensive valves that leak! I was going to ask if there are any check or relief valves in the system which may also leak preferentially in one direction.
FAMIS8041
Both BRS's seem to be moving away from the closest limit, so we should be good for some time.
On the board for today:
Optical lever on the North wall near HAM5, please leave it alone.
No booting of h1sus56 until further notice.
HAM6 doors coming off Mon or Tues.
Please transition back to laser safe when finished working in the evening. This way the morning cleaning/craning/prep work can work in a safer environment.
Continuing work on getting the diagnostic breadboard (DBB) up, at least as far as the front end laser is concerned.
Frequency noise: Looks pretty good actually. A factor of a couple above the reference trace for frequencies between 2 and
5 Hz. Below or equal to elsewhere. Control and error signals are consistent with the reference traces.
Beam pointing: Clearly something is not quite right with this measurement. Could well be that the alignment onto the two
quadrant photodetectors needs to be checked.
Relative power noise: First measurement done with the DBB PMC locked. Typically a factor of ~2 higher than the reference
trace, across the board. Not too dissimilar to the measurement made on Tuesday. dbb_rpn-001.pdf is with the PMC locked, dbb_rpn-002.pdf
is with the PMC unlocked. One can see a small difference in the 7 to 13 Hz region, nothing to worry about really. I was interested
to see if there was a difference in the first place.
Mode scan: Measurement is consistent with that conducted on Monday, namely ~3% in higher order modes.
ISS relative power noise: This measurement does not require the DBB but does need the "real" pre-modecleaner to be locked.
Note that the alignment into the PMC is not optimised because the Picomotor controller was moved for the work around HAMs [1-3].
There's a large discrepancy between the in and out of loop sensor. That's not too surprising, although the scale of the difference is.
The ISS MEDM screen indicates that PDB is the out of loop sensor, which corresponds to the blue trace.
TITLE: 09/28 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
Wind: 6mph Gusts, 4mph 5min avg
Primary useism: 0.02 μm/s
Secondary useism: 0.11 μm/s
QUICK SUMMARY: Vent work ongoin.
Today I finished removing the 288 magnets (144 per pump) from IP7 and IP8. These 2500 L/sec ion pumps were custom built for iLIGO. Each pump consists of (40) ea. 55 L/s noble diode ion pump elements arrayed together in a single pump chamber. The "stripped" pumps will be shipped off to be refurbished.
IO work today:
Tomorrow:
- Cheryl, Corey, Ed, Keita, TJ (restored optic alignments)
LHO TCS maintenance tasks (day 3) per T1700136:
TITLE: 09/27 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: Vent work ongoing
LOG:
I've been having a look at the CO2Y flow meter issue (aLOG 32230). If we look back at the flow rate through July of this year, we see several periods where the "flow" has dropped by up to 30% (see attached time series showing H1:TCS-ITMY_CO2_FLOWRATE). There is zero change in any of the corresponding temperature sensors (laser, manifold, beam dump - all of which are attached to things that are cooled by the water), neither do we see anything in the laser output power.
We know, from measurements at LLO, that we expect the temperature of the laser to change in response to a change in flow rate. For example, we saw a 0.4C decrease in temperature in the LLO laser in response to the flow rate increase of 0.6GPM. There is nothing remotely commensurate here at LHO when the "flow" drops from 3.1GPM to 2.6GPM in mid-July.
There is a single observed drop in temperature around July 18. However, close examination shows that this does not correspond to change in flow - the nearest change in flow rate is approximately 19 hours earlier.
This leads me to believe that the flow rate itself is unaffected and that the electronic interface to the flow meter (the CO2 laser interlock controller) is most likely the source of the problem.
Attached are my notes from Tuesday and today surveying the HAM3 ISI Optical Table and the HEPI Piers.
The ISI Optical Table in HAM3, very similar to HAM2, is tilted down from SW to NE about 0.5mm
The HEPI Piers, like at HAM2, are essentially unchanged during this full corner station sans diagonal vent. The changes are in the noise of my measurement resolutions and I see the NW change of -0.4mm as an error on rod zero or reading.
Bottom Line: The level of the Optical Table is tolerable to IO and there is no indication that the vent has appreciably changed the tilt of HEPI => ISI Stage0.
Addressing the ISIs' table level would require changing locker shims and table balance; or, refloating HEPI and relocking to untilt the table. Both doable, but neither fast--at least a day.
I turned on the internal averaging of the CO2Y flow meter. It is now set to 10s. Note that this is longer that the H1-CO2X, L1-CO2Y, L1-CO2X which are all set to 5s averaging. Given the proclivity of the CO2Y flow meter to glitch - which we think is electronic. This should provide some protection against a transient glitch knocking out the laser.
I have updated H1CDS_POST_O2_OVERVIEW_DETAIL_CUST.adl MEDM screen (launched from the SITEMAP) to show the latest front end models and insert placeholders for new models which will be installed soon as part of SQZ install.
The main differences are:
DAQ area moved to lower right to make room for the new SUS models
ASC shrunk due to losing two models
LSC placeholder for new h1sqz model
h1sushtts added to h1sush2b
placeholder for new h1susopo model on h1sush56
svn version information moved to title bar
h1fw2 added to DAQ area
I torqued the bolts on the IM1 tower, and found many that were loose enough that I could easily get them to travel one quarter of a turn before they tightened up.
The bolts were 1/4-20's on the sides of the towers, and 8-32's on the sides, back, and top of the towers, and some smaller screws that hold the EQ stop brackets.
The 8-32 screws on the top of the tower that moved by one quarter of a turn, included every bolt that is associated with the blade spring attachments and alignment.
The LENGTH signal changed by about -25, PITCH changed by about -300urad, and YAW didn't change.
In my initial inspection, before torquing bolts, I saw sufficient space between all EQ stops and the optic, and between the upper and lower magnet assemblies, so no evidence of a direct mechanical interference.
Plot of the OSEM changes is attached.
Per LLO aLOG 36022, I've added external temperature sensors to the CO2 lasers. The channel they are attached to are H1:TCS-ITMX(Y)_CO2_TEMP_SPARE. These names will eventually be changed to TEMP_LASER_EXTERNAL. They are clamped in place on the top of the laser chassis immediately behind the front end of the laser.
They are reading back temperatures of 19.65C and 20.02C for CO2X and CO2Y, respectively.
I think I gave Jeff bad info yesterday and the h1sushtts model had a DAC identification issue which I fixed this morning. All models on h1sush2b were restarted as part of this investigation.
We need to check if the new h1sushtts model's burt restore and SDF files are correct.
