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  40m Log, Page 326 of 326  Not logged in ELOG logo
ID Date Author Type Categoryup Subject
  12706   Thu Jan 12 13:43:02 2017 ranaHowTosafetyclosing a door

This is one of those unsolved door lock acquisition problems. Its been happening for years.

Please ask facilities to increase the strength of the door tensioner so that it closes with more force.

  12707   Thu Jan 12 13:45:58 2017 SteveHowTosafetyclosing a door

It was requested this morning.

Quote:

This is one of those unsolved door lock acquisition problems. Its been happening for years.

Please ask facilities to increase the strength of the door tensioner so that it closes with more force.

 

  12868   Mon Mar 6 09:12:59 2017 SteveUpdatesafety crane inspection 2017

All 3 cranes inspected by professional Fred Goodbar of Konecranes and load tested with 450 lbs at max reach on Friday, March 3, 2017

 

 

Attachment 1: inspection_2017.jpg
inspection_2017.jpg
  12913   Tue Mar 28 16:47:40 2017 SteveUpdatesafetyProjector bulb is out again

Three replacement bulbs ordered

Rana can discribe how it happened.

IF A LAMP EXPLODES

If a lamp explodes, the gas and broken shards may scatter inside the projector and they may comeout of the exhaust vent.
The gas contains toxic mercury.
Open windows and doors for ventilation.
If you inhale the gas or the shardsof the broken lamp enter your eyes or mouth, consult the doctorimmediately.
Quote:

This bulb was blown out on Feb 4, 2017 after 2 months of operation.

 

 

  12921   Fri Mar 31 10:16:07 2017 SteveUpdatesafetylaser safety glasses annual inspection

Laser safety glasses cleaned in " Dawn Ultra " mild soap - water solution and measured for 1064 nm transmission at 150 mW
 

Attachment 1: march2017.jpg
march2017.jpg
Attachment 2: 2017march.jpg
2017march.jpg
  12927   Tue Apr 4 11:24:21 2017 SteveUpdatesafetyProjector bulb is out again

Shipped out for repair.

Quote:

Three replacement bulbs ordered

Rana can discribe how it happened.

IF A LAMP EXPLODES

If a lamp explodes, the gas and broken shards may scatter inside the projector and they may comeout of the exhaust vent.
The gas contains toxic mercury.
Open windows and doors for ventilation.
If you inhale the gas or the shardsof the broken lamp enter your eyes or mouth, consult the doctorimmediately.
Quote:

This bulb was blown out on Feb 4, 2017 after 2 months of operation.

 

 

It is back and running fine witth bulb  4-13-2017

  12970   Thu May 4 08:00:54 2017 SteveUpdatesafetysafety training

Freshmen Rebecca Zhang as " work study undergrad "  received 40m specific basic safety training yesterday.

  12994   Tue May 16 16:16:16 2017 SteveUpdatesafetysafety training

 Early surfs of India Jigyasa and Kaustubh received basic 40m specific safety traning.

Attachment 1: surfs2017.jpg
surfs2017.jpg
  13095   Wed Jul 5 10:23:18 2017 SteveUpdatesafetyliquid nitrogen boil off

The liquid nitrogen container has a pressure releif valve set to 35 PSI  This valve will open periodically when contains LN2

The exiting  very cold gas can cause burning so it should not hit directly your eyes or skin.  Set the pointing of this valve into the corner.

Leave entry door open so nitrogen concentration can not build up.

Oxygen deficiency
Nitrogen can displace oxygen in the air, reducing the
percentage of oxygen to below safe levels. Because the brain
needs a continuous supply of oxygen to remain active, lack
of oxygen prevents the brain from functioning properly, and
it shuts down.
Being odorless, colorless, tasteless, and nonirritating,
nitrogen has no properties that can warn people of its pres-
ence. Inhalation of excessive amounts of nitrogen can cause
dizziness, nausea, vomiting, loss of consciousness, and death
Attachment 1: liqued_nitrogen_boil_off.jpg
liqued_nitrogen_boil_off.jpg
  13144   Tue Jul 25 14:27:19 2017 SteveUpdatesafetysafety training

Kira Dubrovina and Naomi Wharton received 40m specific basic safety training.

Attachment 1: safety.jpg
safety.jpg
  13406   Mon Oct 30 08:08:06 2017 SteveUpdatesafetysafety training

Udit Kahndelwal received 40m specific basic safety traning on Friday, Oct. 27

  13496   Tue Jan 2 16:24:29 2018 gautamUpdatesafetyProjector periodically shuts itself off

I noticed this behaviour since ~Dec 20th, before the power failure. The bulb itself seems to work fine, but the projector turns itself off after <1 minute after being manually turned on by the power button. AFAIK, there was no changes made to the projector/Zita. Perhaps this is some kind of in-built mechanism that is signalling that the bulb is at the end of its lifetime? It has been ~4.5 months (3240 hours) since the last bulb replacement (according to the little sticker on the back which says the last bulb replacement was on 15 Aug 2017

  13592   Wed Jan 31 15:46:05 2018 SteveUpdatesafetycrane inspection

Annual crane inspection with load tests is scheduled for Monday, Feb 5, 2018 from 8 to 11:30am

Konecranes rescheduled this appointment to: Monday, Feb 12, 2018

  13630   Mon Feb 12 14:56:00 2018 SteveUpdatesafety crane inspection 2018

Our 3 cranes passed  professional  inspection. Fred Goodbar of Konacrane with 450 lbs load at full extension.

Certificates will be posted in 40m wiki as they arrive.

 

Attachment 1: ETMY.jpg
ETMY.jpg
Attachment 2: Vetex.jpg
Vetex.jpg
Attachment 3: ETMX.jpg
ETMX.jpg
  13843   Tue May 15 13:34:30 2018 SteveUpdatesafetysurf safety training

Pooja and Keirthana received 40m specific basic safety training.

  14031   Thu Jun 28 13:12:20 2018 SteveUpdatesafetysurf safety training

Shruti and Sandrine received 40m specific basic safety training this morning.

Quote:

Pooja and Keirthana received 40m specific basic safety training.

 

  14199   Tue Sep 18 14:02:37 2018 SteveUpdatesafety safety training

Yuki Miyazaki received 40m specific basic safety training.

 

  14263   Thu Oct 25 16:17:14 2018 SteveUpdatesafetysafety training

Chub Osthelder received 40m specific basic safety traning today.

  14978   Fri Oct 18 18:13:55 2019 KojiUpdatesafetyLaser interlock looks OK

I've checked the state of the laser interlock switch and everything looked normal.

  14980   Mon Oct 21 11:44:19 2019 gautamUpdatesafetyInterlock reconnected to Innolight controller

We also took this opportunity to re-connect the interlock to the Innolight controller (after it was disconnected for diagnosing the mysterious NPRO self-shutdowns). The diode pump current was dialled down to 0, the interlock wires reconnected, and then the diode current was ramped back up to the nominal 2.1 A. The fan to cool the unit remains mounted in a flaky way as we couldn't locate the frame Chub had made for a more secure mounting solution. 

It seems like the pointing of the beam out of the laser head varies somewhat after the startup - I had to adjust the pointing into the PMC a couple of times by ~1 full turn of the Polaris mount screws, but the IMC has been locked (mostly) for the last ~16 hours.

Quote:

I've checked the state of the laser interlock switch and everything looked normal.

  15508   Thu Aug 6 22:57:20 2020 gautamUpdatesafetyNew live HV Supplies

Be aware that there is now a KEPCO HV supply that is energized, sitting on the floor immediately adjacent to the OMC rack, east of the AP table. It is currently set to 100 V DC, and a PI PZT installed on the AP table has its 3 PZTs energized by said supply (via an OMC piezo driver). I will post pictures etc of the work from the last 10 days over the weekend.

  15544   Fri Aug 28 11:41:23 2020 gautamBureaucracysafetyCrane inspection 2020

Mr Fred Goodbar of Konacrane was in the lab 830am-1130am today. All three cranes in the VEA were inspected, loaded with 450lb test weights, and declared in good working condition and safe to use.

  1. Apparently, the clackity noise heard when running the crane at the south end is a known problem - the crane was opened up and inspected sometime in the past, and no obvious cause was found. This is not expected to affect the usability of the crane.
  2. The travel speed of the cranes is slow - but this is apparently intentional, on the request of Steve V.

The interferometer subsystems appear normal after the inspection. 

  15932   Wed Mar 17 15:02:06 2021 gautamUpdatesafetyDoor to outside from control room was unlocked

I came into the lab a few mins ago and found the back door open. I closed it. Nothing obvious seems amiss.

Caltech security periodically checks if this door is locked but it's better if we do it too if we use this door for entry/exit.

  15938   Thu Mar 18 12:35:29 2021 ranaUpdatesafetyDoor to outside from control room was unlocked

I think this is probably due to the safety tour yesterday. I beleive Jordan showed them around the office area and C&B. Not sure why they left through the control room.

Quote:

I came into the lab a few mins ago and found the back door open. I closed it. Nothing obvious seems amiss.

Caltech security periodically checks if this door is locked but it's better if we do it too if we use this door for entry/exit.

 

  12998   Thu May 18 15:20:29 2017 jigyasaSummarytelescope designTelescope Design for the Gig-E cameras

With the objective of designing a telescope system for the Gig-E, a system of two lenses is implemented. A rough schematic of the telescope system is attached. Variables in the system include the focal lengths of the two spherical lenses(f1, f2), distance between the lenses(t), distance between the test mass and the lens combination(u), distance between the other lens and the sensor(v). Also the size of the object to be desired ranges from 3’’ which is the size of the test mass to 1’’ which is approximately focusing on the beam spot implying that the required magnification ranges from 0.06089 to 0.1826 (since the sensor image circle size if ¼”)
The lenses are selected to be 2” in diameter so as to ensure sufficient collected power.

Going through the focal lengths available, namely 50, 100, 150, 200, 250 mm, and noting that the object distance would be within the ranges of 1500 to 2500 mm, plots of various accessible u and v for different values of t were obtained. This optimization was done to ensure the proper selection of the lenses. Additionally, a sensitivity analysis was performed and plots depicting the dependence of magnification on the precision limiting measurements of u (1 mm) and t (5 mm) were obtained. (These were scatter plots quantifying the deviation from the desired magnification ranges). The plots depict the error term induced on the magnification if there was an error in measuring the distance between the lenses as 5mm and if the precision in measuring the object to lens distance by 1mm.

The telescope design might be limited by spherical aberrations and coma, which might be resolved by either using aspherical lenses or by increasing the f-number (typically with an f number around 5 or 6). The use of aspherical lenses particularly parabolic lenses was considered, however this was found to be quite an expensive route. 

Analyzing the plots and taking into consideration the restrictions of the slotted lens tubes, the precision in measurement of the distances, a 150 mm- 250mm focal length solution is proposed. With a diameter of 2”, the f number is computed to be 2.95 and 4.92. With this combination and the object distances lying between 1500 to 2500 mm, the image distance to the sensor varies between 51 to 100mm. So a slotted lens tube controlling the distance between the lenses would be required.

I also considered a combination of focal lengths 250mm and 250mm, as then both of the lenses would at least have an f number of 4.92. The results for this combination are also attached. The image distance from the lens combination is about a 100 to a 140 mm. However, this would require much longer slotted length tubes thereby adding to the cost of the system. The number of accessible u-v points is the same as that for the 150-250 combination. 

I am still trying to search for a much more concrete way of quantifying aberrations.

Attachment 1: ray.png
ray.png
Attachment 2: Schematic.png
Schematic.png
Attachment 3: 150-250uv.png
150-250uv.png
Attachment 4: 150-250error.png
150-250error.png
Attachment 5: 250-250.png
250-250.png
Attachment 6: 250-250error.png
250-250error.png
  13000   Mon May 22 10:15:14 2017 jigyasaSummarytelescope designLens tubes and object distances

Since the f numbers of the lenses in the proposed design with biconvex lenses are a little less than 5 and the conjugate ratio(that is the ratio of object to image distance) is greater than 5, I explored the use of plano convex lenses, but with the same focal lengths, the accessible u-v range is restricted with the planoconvex rather than biconvex lenses.
On Friday, I had a discussion with Gautam and Steve about the hardware that is the cylindrical enclosures for the camera and the telescope and we examined two such aluminum cylindrical enclosures. One of them was the one being currently employed for the cameras. The dimensions were measured and the length was found to be 8’’ and an outer diameter of 26 cm within an error of 0.5 cm.
The other enclosure was longer with a length of 52 cm(±0.5 cm), outer diameter of 10”(±0.1”) and an inner diameter of 23.7cm(±0.1cm). Pictures of these enclosures are attached.
Both of these enclosures have internal optical rail to mount the camera and the telescope system. Depending on the weight of the telescope system(that includes the weight of the slotted lens tubes, the lenses), it might be more efficient to clamp the telescope system itself on the rails with the low weight camera mounted on the lens tube.
I also went around to get an idea of distance of the GigE from the test masses. This was just a step to verify if the object distances were really in the ranges being taken into consideration, that is between 1500 and 2500 mm. I also tried to cross check the measurements with the CAD drawing of the 40m. However, as I have been informed, the distances in the CAD version are not updated.

The distances from the optic to the CCD detector would range from around 75.1 cm for MC2, 94.01 cm for ITMX, 97.21 cm for ETMX, 117.19 cm for ITMY and 88.463 cm for ETMY. The illuminator for the ETMY was disconnected, so Gautam helped me access the manual lamp control to enable me to take measurements.
The values for ETMX, MC2 and ITMY are subject to an error of ±1’’. Due to a lot of obstructions, the values for ETMY and ITMX may be subject to a lot more error. Even so, these distances are clearly less than 2 meters, prompting me to run the simulations again and verify that the chosen combination is still useful.

As for the slotted lens tubes to mount the 2” lenses, the following options are available on the Thorlabs catalog. CVI and Edmunds do not seem to offer much of the stackable lens tubes.

SM2L30C is a lens tube onto which the optic can be mounted without the need of a spanner wrench. It also has a length of 3”. However, it has a rotatable slip shield which can be rotated open as and when the access to optic is required. However, there might be a slight compromise with rigidity here.

SM2L30 is a lens tube with internal thread depth of 3”, the optic can be mounted using spanner wrench and a retainer ring. The optic cannot be accessed from both ends of the tube here.
SM2M30 is a lens tube with no external threads, therefore lens tube couplers would be required to stack the tubes. The optic is accessible from both ends here though.

Considering the merits and demerits of all these available options, the use of SM2L30 might be considered as it provides a quick and efficient way of stacking multiple lens tubes. As for accessing the optic from both sides, using multiple tubes helps overcome the problem and still ensures that we are able to access a number of separation distances as per requirement.
Thorlabs also offers an internal C to external SM2 adapter so that the lens tube could be fixed onto the C mount of the camera. 

I would be examining the use of 1" diameter lenses for the eyepiece as suggested by Rana, as that might give us more flexibility. 

Attachment 1: Pictures1.pdf
Pictures1.pdf Pictures1.pdf Pictures1.pdf Pictures1.pdf
  13004   Mon May 22 15:01:41 2017 jigyasaUpdatetelescope designUpdated Telescope design with 1'' eye piece

I examined the use of a single lens system for the available range of focal lengths, for the required magnification and found that a focal length of at most 100 mm would be required to sufficiently cover the object distance range. This would greatly compromise with the f-number and hence lead to a lot more spherical aberrations.

Therefore, a two lens system would be more useful to implement. Using an eyepiece of 1” puts an additional constraint on the system such that the separation between the lenses must now at least equal or be greater than half the image distance from the first lens to ensure that no light from the light cone is lost. This is clarified in the schematic. The image from the first lens in absence of the second lens would form at point A, subtending an angle θ. In order to ensure that no part this light cone emerging from the first lens is lost, the second lens must be placed at a distance atleast v/2 from the first lens.

A combination of 125mm focal length 2” diameter objective with a 250 mm 1” eyepiece covers the required range of object distances (650mm to 1500 mm). Increasing the focal length of the eye piece increases the minimum object distance accessible to 700 mm. 

A glance at the accessible u, v points shows that all magnifications are not possible at a given object distance. To image the entire surface of the test mass, a distance of at least 1.25m is required from the objective, while a beam spot of 1'' diameter can be imaged easily at upto 1200 mm from the objective . This holds true even for the 150-250 mm biconvex 2" lens combination proposed earlier. 

If this sounds reasonable, we could proceed with ordering the lenses.

Attachment 1: 1incep.pdf
1incep.pdf
  15877   Mon Mar 8 12:01:02 2021 Paco, AnchalSummarytrainingInvestigate how-to XARM locking

[Paco, Anchal]

- Started zoom stream; thanks to whoever installed it!
- Spent some time trying to understand how anything we did last thursday lead to the sensing matrix change, but still cannot figure it out. 
- Tracking back on our actions, at ~10:30 we ran burt Restore with the 08:19/.*snap and in lack of a better suspect, we blame it on that action for now.

# ARM locking??
- Reading (not running) the scripts/XARM/lockXarm.py script and try to understand the workflow. It is pretty confusing that the result was to lock Yarm last time.
- It looks like this script was a copy of lockYarm.py, and was never updated (there's a chance we ran it for the first time last thursday)
- *Is there a script to lock the Arms?* Or should we write one? To write one, we first attempt a manual procedure;
    1. No need to change RFPD InMTRX
    2. All filters inputs / outputs are enabled 
    3. Outputs from XARM and YARM in the Output matrix are already going to ETMX and ETMY
      - Maybe we can have the ARM lock engage by changing the MC directly?
    4. Change C1:SUS-MC2_POS_OFFSET from -38 to -0, and enable C1:SUS-MC2_POS_OFFSET_ON
    5. Manually scan MC2_POS_OFFSET to 250 (nothing happens), then -250, then back to -38 (WFS1 PIT and YAW changed a little, but then returned to their nominal values)
      - Or maybe we need to provide the right gain...
    6. Disabled C1:SUS-MC2_POS_OFFSET_ON (back to nominal state)
    7. Look into manually changing C1:LSC-XARM_GAIN;
      From the command line using python:
      >> import epics
      >> ch_name = 'C1:LSC-XARM_GAIN'
      >> epics.caput(ch_name, 0.155) # nominal = 0.150
      - Could be unrelated, but we noted a slow spike on C1:PSL-FSS_PCDRIVE (definitely from before we changed anything)
      - Still nothing is happening
    8. Changed the gain to 0.175, then back to 0.150, no effect... then 0.2, 0.3 ...
      - Stop and check SUS_Watchdogs (should not have changed?) and everything remains nominal
      - Revert all changes symmetrically.
      - Could we have missed enabling FM1?
      - Briefly lost MC lock, but it came back on its own (probably unrelated)

- Wrap it up for the day. In summary; no harm done to our knowledge.

  15878   Mon Mar 8 12:40:35 2021 gautamSummarytrainingInvestigate how-to XARM locking

For the arm locking, the "Restore Xarm (XARM POX)" script from the "IFO_CONFIGURE" MEDM screen should get you there (I just checked it and it works fine). It is worth getting a hang of the PDH signal chain (read what the script is doing and map it to the signal chain) so you get a feel for where there may be offsets, saturations, what the trigger logic is etc. The LSC overview screen is supposed to be pretty intuitive (if you think it can be improved, I'd love to hear it but please don't change it without documenting) and there are also the webviews of the simulink models (these are RO so feel free to click around, for the LSC the c1lsc model is the relevant one).

  15912   Fri Mar 12 11:44:53 2021 Paco, AnchalUpdatetrainingIMC SUS diagonalization in progress

[Paco, Anchal]

- Today we spent the morning shift debugging SUS input matrix diagonalization. MC stayed locked for most of the 4 hours we were here, and we didn't really touch any controls.

  15919   Mon Mar 15 08:55:45 2021 Paco, AnchalSummarytraining 

[Paco, Anchal]

  • Found IMC locked upon arrival.
  • Since "allegra" was set up as an additional workstation, we tried using it but discovered the monitor ist kaput. For the sake of debugging, we tested VGA and DVI inputs and even the monitor lying around (also labeled "allegra") with no luck. So <ssh> it is for now.

IMC Input sensing matrix

  • Rana joined us and asked us to use Rossa for now so that we can sit socially distantly.
  • Attaching some intermediate results on our analysis as pdf and zip file containing all the codes we used.
  • We used channels C1:SUS-MC1_USSEN_OUTPUT  (16 Hz channels) and so on which might not be the correct way to do it as Rana pointed out today, we should have used channels like C1:SUS-MC1_SENSOR_UL etc.
  • During the input matrix calculation, we used the method of TF estimate (as mentioned in 4886) to calculate the sensor matrix and inverted it and normalized all rows with the maximum absolute value element (we tried few other ways of normalization with no better results either).
  • We found the peak frequencies by fitting lorentzian to the sensor data rotated by the current input matrix in the system. We also tried doing this directly on the sensor data (UL for POS, UR for PIT, LR for YAW and SD for SIDE as this seemed to be the case in the old matlab codes) but with no different results.
  • The fitted peak frequencies, Q and amplitude values are in fittedPeakFreqs.yml in the attached zip.
Attachment 1: IMC_InputMatrixDiagonalization.pdf
IMC_InputMatrixDiagonalization.pdf IMC_InputMatrixDiagonalization.pdf IMC_InputMatrixDiagonalization.pdf
Attachment 2: inputMatrixCalculationMC.tar
Attachment 3: freeSwingMC.py.tar
Attachment 4: SUSfreeswing_1299514263.txt.tar
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