PSL Weekly Report - 10 Day Trends FAMIS #6192

70W install is ongoing

PT210B acting weird

Gerardo noticed this.

Alarms reconfigured, ROC MEDM summary page expanded

Kyle, Dave:

Two changes to the Vacuum cell phone alarms:

H0:VAC-MY_CP4_253_REGEN_TEMP_ALRM_INTLK	Cell phone texts bypassed for 24 hours, expires Tue Mar 20 10:40:38 PDT 2018
H0:VAC-LY_Y4_PT124B_PRESS_TORR	HIGH alarm raised from 5.0e-08 to 1.0e-07 Torr

H1CDS_ROC.adl MEDM improved to show alarm levels and current value. Red border follows these alarm levels.

LVEA Laser Safe

   Transitioned the LVEA to laser safe. Locked the ISCT6 and Squeezer cabinets. No other issues noted. 

Increased CP4 SETPOINT to 115C from 110C

Recall that TC1 has an offset and that it is under-representing the actual temperature it is exposed to by 6C - 10C.  

Also while at Y-mid, I closed the exhaust valve on the turbo that is pumping CP4, closed the foreline isolation valves and opened the scroll ballast/purge plug.  This allowed room air to purge, under viscous conditions, any water that may have condensed between the scroll stages since stopping the UHP N2 purge gas the other day.  I restored the configuration after a minute or two of viscous purge.  

I used the hand-held TC meter to measure the underside of CP4's vacuum vessel (1 ft. radius around vent/purge nozzle represented by TC3) and found the average temperature to be around 65C.  It would be interesting to see if we could lessen the temperature striation we are experiencing (HOT air resides at high elevations cooler air found at lower elevations) by heating the inner LN2 reservoir using the regeneration system. 

Kyle on site doing Daily Check

I'll be at Y-mid checking in on the CP4 bake.  I'll also "pop" in and look at the X-end and LVEA purge-air supplies.  Gerardo M. has been notified.  

I expect to be hear less than 90 minutes and will make a comment to this entry when I leave.  

Turbo pumping CP4 very close to overheating -> Valved-out turbo's UHP N2 purge and foreline pressure dropped from 2.5 x 10-2 Torr to 7.4 x 10-3 Torr.  Also, stopped PLC PID bake, lowered the SETPOINT to 110C down from 130C.  

We easily have enough heat now with the extra 10kW but are suffering from a significant Top to Bottom temperature gradient.  This is a fundamental consequence of this initial setup and can't be easily addressed without stopping the current bake-out and then making significant modifications.  Eliminating leaks between the insulating blankets would help some and can be done while bake is in progress.  Also, use of the Regeneration System could also lessen the gradient but comes with its own added risks.  

1555 hrs. local -> Kyle leaving site now.  

high alarm level for PT243 increased from 5.0e-08 to 1.0e-07 Torr

Kyle has requested the high alarm level for PT243 (Y1 beam tube, adjacent to MY) be increased as it is now reading above 5.0e-08 Torr. He requests it be increased to 1.0e-07. I have done this and restarted the alarm system.

H0:VAC-MY_Y1_PT243B_PRESS_TORR   (VE gauge, MY Y1-beamtube, CC  )

current value = 5.419e-08 Torr

low alarm level = 1.000e-10  Torr

high alarm level = 1.000e-07 Torr

CP4 bake-out control thermocouple offset

(Regarding camera view of CP4's bake-out control PLC display) 

I noticed that TC1 has acquired an offset as of this morning.  This TC is the closest to the heat source and, until this morning, has consistently been the "hottest" of the four displayed TCs on the PLC display.  Now, it is consistently below TC2 which is the next TC downstream in the heated air flow.  I am sure that this is the result of its extension wire connector being disturbed during the installation of the second duct heater this morning.  This extension wire connector is located very near where the work was being done and would have been in the way.  As the TC is what the PLC is using to determine the heater output, it is important that it represent the actual temperature of the air exiting the heater.  If this TC's value differs too much from TC2 or becomes "bogus" we could have a problem of the PLC overheating or underheating.  I'll keep a close eye on it over the weekend.  

Verbal alarms high vacuum alarms

Verbal alarms just reported high vacuum alarms at BSC2, BSC7, HAM6 and PT245. I can understand the ones at HAM6 and PT245 (CP4), but I'm not certain about the ones at BSC2 and BSC7. Is this due to the change in verbal alarms code [alog 41046]?

Minute trends for last 30 days.

I don't see any reason why we should be getting any alarms from the Corner Station.  PT110, PT120 and PT170 shouldn't be alarming at current pressures.  

I don't know what the alarm levels are currently set at for the Y-mid station (PT210, PT245 and PT246) but we are monitoring regularly from home due to the fact that we are currently baking out CP4.  I think that Chandra's intention was for Dave B. to have recently increased PT210's alarm threshold from 5 x 10-8 Torr to 1 x 10-7 Torr.  This was so as to reduce potential nuisance alarms resulting from the Y-mid pressure rising as CP4's temperature slowly increased to its eventual maximum of 130C (Sunday?  Monday?).  

PSL 70W Amplifier Installation Update #8

J. Oberling, E. Merilh

We began today by searching for a smaller micrometer to replace the rather large one on the 2nd mode matching lens mount.  We found one in the PSL enclosure and Ed installed it, see 1st picture.  We were then able to move the dog leg up by 1 row of holes, which cleared the interference with 70W amplifier output beam path.

We then mounted and installed 2 HR mirrors to re-direct the beam back online for the 70W amplifier.  We used a couple of mirror pedestals from the IOO cabinet and used spare HR mirrors from the PSL spare stock.  We then proceeded to align the beam.  We started with the mode matching lenses, as the 2nd lens needed to be removed to install the shorter micrometer.  We then realigned through the dog leg, using M08 and M34 to bring the beam up to the level for AMP_FI.  We used a beam target to to align the beam down the required row of holes and at the right height.  We then installed AMP_FI, AMP_WP02, and AMP_WP03 and checked that the beam was centered on them all.  Using the same alignment target, we then used our 2 new HR mirrors to align the beam down the required row of holes for AMP_M01 and the new FE DBB beam path.

At this point we placed the Thorlabs beam profiler and spent some time optimizing the lens positions.  The best waist we could get today was 365µm diameter horizontal and 344µm diameter vertical, likely due to the slightly increased optical path length due to AMP_FI, AMP_WP02, and AMP_WP03.  This is close enough for rough mode matching, so we moved on.  We roughly placed the 70W amp in its location so we could install AMP_M02 and mark its location for alignment purposes.  We then removed AMP_M02 and the 70W amplifier and installed AMP_M01.  Using the same alignment target, and the 2nd new HR mirror and AMP_M01, we aligned the beam down the row holes between AMP_M01 and AMP_M02.  This is a very rough starting alignment for the 70W amplifier, likely not close to the final alignment but at least somewhere to start.  We then installed AMP_M02 and AMP_M06, and placed beam dumps so all beams (leakage beams through AMP_M01 and AMP_M02 and the main beam reflected from AMP_M02) were blocked.  Finally, we installed the 4 beam dumps for AMP_FI.

I've attached a few pictures of the new layout.  The 1st shows the new, shorter micrometer.  The 2nd is an overview shot of the pre-70W amp beam path.  The 3rd shows the mode mathcing lenses, as well as WP02 and PBS02 in their new homes.  The 4th shows the re-located dog leg and AMP_WP02 at the entrance to AMP_FI.  The final picture shows AMP_WP03 at the exit of AMP_FI, the 2 new HR mirrors, AMP_M01, AMP_M02, and AMP_M06.  The 70W amplifier will sit in-between AMP_M01 and AMP_M02.

Next week, Peter will begin the process of aligning the 70W amplifier and optimizing the mode matching.

HAM6 squeezer work

Nutsinee Terry Daniel

OPO locking:

• With the ISI no longer locked the ~1kHz acoustic peak is a factor of a few lower and the OPO locking needs correspondingly less range. The lock also looks much better now.
• We copied the guardian from the SHG and updated it for the OPO. It seems to work.
• The power coupled through the fiber was increased by a few. We get just under 6mW onto the OPO REFL diode.
• OPO REFL Photodiode DC: Unlocked 5.8mW, Locked 2.2mW. The dip in reflection therefore is 62%

Fibers:

• We tried the waveplates in the green pump path and we are able to go as low as 0.7mW for the rejected light. The adjustment was somewhat cumbersome, since both waveplates needed to be rotated simultaneously to make further improvements towards the end.
• We also tried the manual waveplates in the seed path. We were able to get the rejected light up and down by about a factor of 4. It seems difficult to do better by hand.

Translation stage:

• We were able to move the lens translation stage using the PI controller.
• We didn't try the oven translation stage since we had no feedback, if it is moving.

Next:

• We need to realign the pick-off beam towards the homodyne detector,
• and find the red/green double resonance in the OPO.

Latest version of VerbalAlarms running on alarm0

The newest version of VerbalAlarms is now running on alarm0 (alarm handler computer). I've been running it on zotws8 all week and I think it is stable enough for control room use. If there are any issues with it, running the normal "VerbalAlarms -dc" will start the old one.

There will be a longer alog with details of this new version on another day.

Pcal alignment work at X-end, seems to have been successful

JimW, NikoL, JimW, ArijitS, RickS

This morning, we went into X-end to try to restore the alignment of the Pcal beams.

First, we tried tapping on the Pcal periscope flexures with the newly-acquired aluminum hammers.  That was not as successful as we had hoped.  The beams didn't move as we expected, which probably means that the tapping was not moving the periscope the same way it had shifted during the addition of the vibration absorbers and the "baffles and shields" hardware.

In the end, we used the adjustable mirror mounts on the periscope to restore pointing to the ETM target mounted on the suspension frame.

We also adjusted the centering on the 4th lower beam periscope mirror (M4)r.  We name the lower beam relay mirrors M1-M5 starting at the Tx module.  We adjusted M2 pitch to bring the beam up on M3, then adjusted the pitch of M3 to lower the beam on M4.  With a couple of iterations, we significantly improved the centering of the lower beam on M4.

We then adjusted the relay mirrors in the Receiver Module to center the beams on the aperture of the Rx integrating sphere.

We also adjusted the compression of the upper periscope flexures.  As found, the upper gaps were slightly more that 0.230".  We adjusted the flexure compression screws to reduce the gaps to slightly less than 0.210", increasing the pre-load forces constraining the periscope structure.

Photos of the beam positions on the ETM target and at the entrance to the Rx module integrating sphere are attached.

Ops Day Shift Summary

Pcal ETMY baffles and shields installation work complete

StephenA, AlenaA, NikoL, MarekS, JimW, RickS

Jim and crew completed the installation of the shield panels today.  They also adjusted the compression of the upper-right (when viewed from the ETM) flexure gap to ~0.220".

Everything seems to be installed as designed.

NikoL, MarekS, TravisS, RickS

Began assessing the centering of the Pcal beams on the input and output apertures using targets mounted to the Pcal window flanges on the A1 adapter.  We plan to continue this work in the morning, going inside the vacuum envelope to assess centering on the Pcal periscope relay mirrors. 

We plan to install the Pcal target on the ETM suspension cage for this work.

Reflections of the beam tube surface in the baffle not to be confused with smooth finish of the baffle on this photo

Here is a photo logging S/N of periscope components, collected during the above PCal Yend Baffle and Shields install effort. These articles conveniently do not appear to be assembled into any of the existing D1200174 assemblies. 

:(