40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
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ID Date Author Typeup Category Subject
  1738   Wed Oct 5 19:47:38 2016 awadeMiscSafetyLaser containment curtain

Laser safety curtain has now been installed.

 

 

 

Quote:

I have asked Nichole Washington to book a maintenance job to have the laser curtain installed in the PSL lab.  I unpacked the items from delivery tube and they are consistent with the packing list.  All the necessary parts are in the entrance area of the lab.  

 

  1748   Thu Oct 13 16:38:48 2016 awadeMiscElectronics EquipmentSR780 broken

SR780 is not booting. It appears to be getting as far as the boot screen and then cycles off and on again. Send for a service?

  1752   Tue Oct 18 11:26:00 2016 awade, YinziMiscOtherLab tour, thermal controls and electronics meeting with Yinzi

Yesterday I showed Yeyuan Xin (Yinzi), a new undergraduated student, the PSL lab and went over some of the thermal control elements of the CTN experiment with her.  I also showed her the electronics workshop and she had a look at the heater driver circuit.  I have given her some copies of the current Python scripts that interface with the modbus and she has copies of the Perl PID scripts to look over.

So far she has two tasks to look into: translation of the Perl PID scripts to python; and, improving and building a basic low noise heater driver.

  1756   Fri Nov 4 12:59:11 2016 awadeMiscDrawingsVacuum tank view port masking shields

I have asked Eddie to have a look at some masking shields for the vacuum tank's 8" viewports.  He will look at the drawings and seek out someone to build and polish them. This is to help with reducing the emissivity as viewed from inside the tank looking towards the viewports.  Fused silica has a epsilon>0.75, a shiny mask coving all but the spots where light is coupled in/out should improve the radiative thermal isolation from the tank.

I've attached the drawings of my initial sketch. In the process I also did an update of all the Solidworks assemblies that we have in the SVN, these were largly drawn in the student version of Solidworks and were useless for generating drawings and assemblies.  I have now updated all the parts and assemblies, there are now no student version files. All of these has been updated in (root)/trunk/CTNLab/current/drawings/dual_refcav/ of the 40m SVN . In an effort to reduce the entropy of this directory, I have broken the reference cavity drawings into subassembly folders so individual sub-systems can be edited separately. 

Is 0.5" a big enough hole for our beams to get in/out?

To get the drawings follow instuctions here: https://wiki-40m.ligo.caltech.edu/How_To/Use_the_SVN_archive

Attachment 1: AssembledEndShield.PDF
AssembledEndShield.PDF
Attachment 2: EndMaskShieldingWindow.PDF
EndMaskShieldingWindow.PDF
Attachment 3: FixingBlocks.PDF
FixingBlocks.PDF
Attachment 4: Fully_Assembled_Tank_Stack_And_Cavites_ExplodedView.PDF
Fully_Assembled_Tank_Stack_And_Cavites_ExplodedView.PDF
Attachment 5: spingyband.PDF
spingyband.PDF
  1776   Tue Nov 29 17:09:53 2016 awadeMiscComputersConfiguring PSL network

The PSL network is presently sitting disconnected from the ATF network and the internet.  This is kind of a pain for working on the lab computers: i.e. updating, installing packages, checking web based manuals etc. It would also be nice to be able to ssh in from my Mac to the EPICS interface.

After poking around the router and tracing the Ethernet cables from the ATF lab into the PSL lab there is a link, it was just not plugged in. The map of the network is HERE, it hasn't been updated since Oct last year. When I plug the 3com switch in the PSL lab into the remaining port on the BEEFSX41 router I can see the internet from PSL if I enable DHCP.  I am give a 10.0.1.xxx address. However to reach computers within the PSL lab I need to manually stipulate a 10.0.0.xxx address for my computer or it can't find fb2, acromag1 or the acromag cards.  Not sure if we need to move all the PSL computers on the 10.0.1.xxx group of IP addresses or whether the PSL lab switch can be configured.  This is not my area of expertise. 

  1798   Tue Jan 3 11:53:39 2017 awadeMiscOtherFlow bench lights are out, need replacing

The PSL lab flow bench fluro lights have died.  Its not obvious how we get to the tubes as the difuser pannel is designed to not be taken out. They may need to be accessed from above or from front.  I will call the company today and see how this is done.

 

Update (Tue Jan 3 16:14:14 2017): called Pure Aire, the lights are replaced from the top.  All the stuff stacked on top will need to be removed and four screws removed to open the top pannel.

  1806   Mon Jan 9 15:20:07 2017 awadeMiscEnvironmentPower outage in lab last night.

There was a power outage in the lab last night.

  1823   Mon Mar 6 20:49:18 2017 awadeMiscOtherFlow bench lights are out, need replacing

Finally cleared stuff off the top of flow bench.  Need to reorder 2x Phillips F72T12/CW, 56 W.  

These bulbs have a Hg marker, so they may need special disposal for mercury containing waste. 

Quote:

The PSL lab flow bench fluro lights have died.  Its not obvious how we get to the tubes as the difuser pannel is designed to not be taken out. They may need to be accessed from above or from front.  I will call the company today and see how this is done.

 

Update (Tue Jan 3 16:14:14 2017): called Pure Aire, the lights are replaced from the top.  All the stuff stacked on top will need to be removed and four screws removed to open the top pannel.

 

  1841   Thu Jun 22 14:55:37 2017 awadeMiscElectronics Equipment30A @ 125 V plug install for UPS

I've bought a UPS to help the lasers + computer ride out the frequenent power outages in Bridge West.  Its needs a 30A plug.  

A job is booked in the AiM's system (#24141) work will take place 0800 Tuesday 27 June. They may need to power down adjacent power while routing cables.  

  1850   Thu Aug 3 19:59:10 2017 awadeMiscFSSPositive HV supply to FSS showing no current

Despite the Craig's OLG TF looking ok for the north/south common path TF, the lock is breaking out into ringing with very small disturbances on the table.  Its not clear whats going on here. I through maybe either the PZT or EOM actuators were railing somewhere. The rms noise of the north error signal is typically around 18 mV on the north error signal monitor and 130 mV on the south: something is definitely not right there. this may be the previous problem that we had with south ringing.

I was looking around at the power supplies (just to check) and noticed that the positive +200 Kepco is registering no current on the front panel.  This could be the dial but it could also indicate that maybe we're missing on rail of the HV. This would be a problem for the EOM actuation stage of the FSS loop. 

Not sure how I'm going to test. I might open up the field boxes and stick a multi meter in there to see if +ve HV is actually getting there.

Attachment 1: 2017-08-03_19.47.36.jpg
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  1907   Sat Sep 9 18:20:38 2017 awadeMiscDrawingsFour channel BNC breakout for Acromag front panel and other general use

The BNC keyed holes punched in the front of the Acromag crate (LIGO-D1600135) are all 0.5".  This means that none of the standard insulated panel BNC feed through fit (the in-line types are all 9.7 mm), I seem to only be able to find the 0.5" in the PCB mounted right angle BNC receptacles. Right now all that is holding the current BNCs in from rotating are lock washers and almost INHUMAN TORQUE FORCES.

Johannes had a 4-channel BNC to Sub-D 9 that he had procured from Downs (Old DCC D090415).

However, this part is now obsoleted and they have run out.  I made a quick board layout in Eagle (attached below with all of the Gerbers files).  I added male and female sub d receptacles and included an optional screw terminal breakout.  We often need quick break outs for multiple BNCs and end up making dangly octopus creations.  We might as well have a bunch of properly made breakouts.  

If there are no objections I will order a small batch some time next week.

 

Attachment 3: BNC_Front_Pannel_Connectors.zip
  1915   Wed Sep 13 13:59:04 2017 awadeMiscDrawingsFour channel BNC breakout for Acromag front panel and other general use

I ordered BNC PCB breakout board parts yesterday. Purple.

Expect a 12 day turn around.

Quote:

The BNC keyed holes punched in the front of the Acromag crate (LIGO-D1600135) are all 0.5".  This means that none of the standard insulated panel BNC feed through fit (the in-line types are all 9.7 mm), I seem to only be able to find the 0.5" in the PCB mounted right angle BNC receptacles. Right now all that is holding the current BNCs in from rotating are lock washers and almost INHUMAN TORQUE FORCES.

Johannes had a 4-channel BNC to Sub-D 9 that he had procured from Downs (Old DCC D090415).

However, this part is now obsoleted and they have run out.  I made a quick board layout in Eagle (attached below with all of the Gerbers files).  I added male and female sub d receptacles and included an optional screw terminal breakout.  We often need quick break outs for multiple BNCs and end up making dangly octopus creations.  We might as well have a bunch of properly made breakouts.  

If there are no objections I will order a small batch some time next week.

 

 

  1936   Sat Sep 30 17:05:10 2017 awade, CraigMiscComputersCrontab job added to acromag1 to log system state

Craig has written a python script called channelDumper.py that trawls the modbus/db/ folder, parses the .db files to find all the EPICS channel names and writes them to disk. A complimentary function channelWriter.py grabs these system state files and reinstates channel values from previous channel dumps on demand. Both work great for recovering system states quickly when cycling modbusApp EPICS server when we are changing channels around.

I have now placed a hourly job in the crontab (command crontab -e) that dumps the state of all channels.  These are stored in /CTNWS/data/ directory on acromag1. This should help us track changes and recover quickly from system failures.

 

This is the job placed on the crontab task list:

* */1 * * * bash /home/controls/scripts/cronlauncher_channelDumper.sh

 

cronlauncher_channelDumper.sh is a bash wrapper script so that all the necessary environment variables (ussually in .bashrc) are avaliable to the task. All these scripts are in the CTN directory of the 40m SVN.

  1938   Sun Oct 1 15:59:57 2017 ranaMiscComputersBURT

This is very similar to the BURT and autoBURT system that we usually run with EPICS. It does hourly snapshots of all settings and restores them on boot up. You can also make safe snaps and there is a program 'burtgooey' which allows you to select which time to restore from for manual save/restore. Its been running at the 40 since 1998; seems reliable. Maybe Jon also has something like this running in TCS lab?

Quote:

Craig has written a python script called channelDumper.py that trawls the modbus/db/ folder, parses the .db files to find all the EPICS channel names and writes them to

  2005   Sat Dec 9 20:24:19 2017 awadeMiscPurchasesGas orders

I've ordered a refill for the N2 gas cylinder.   I got the slightly better stuff so we also have the option to use it for venting at a later date. Airgas part number NI UHP200 (Ultlra High Purity 5.0 Grade Nitrogen, Size 200 Cylinder, CGA-580)

For future reference the LIGO use recommendations and order instructions can be found at: https://dcc.ligo.org/LIGO-T1600478

 

  2032   Fri Jan 5 20:49:20 2018 awadeMiscOtherPower pins broken off on spare (original PSL lab) NF1811 detector

I borrowed the spare (original) New Focus 1811 (DC-125 MHz) photo detector from the PSL lab to use in the WOPO experiment.  It is broken: spoiler alert the pins on the power in have been bent and some look snapped off, see pictures.

On plugging it into a power supply and looking at the DC coupled output, I found that it was on the negative rail with a high impedance load and when 50 Ω loaded had a 25 Hz oscillation.  This confirms a previous vague suspicion that something was up. We had previously switched this particular unit out for one borrowed from the 40m.  It looks like it may have not been measuring a beat note after all, although the issue preventing us from first seeing a BN was also a bad set of temperature tunings for the lasers at the time.

I thought maybe some internal circuitry was busted, but when looking closer at the pins in the power-in plug it looks like they have been damaged. If its missing ground, most LM79/79 regulators will pass full voltage, otherwise only a single supply will also prevent proper operation.

At some stage I'll open it up, work out the feed through dimensions and replace it with a more robust connector. Or an identical one if Digikey has it.  It might also be a good time to inspect the RF transimpedance stage and see what our options are for lowering the 7kΩ first stage amplification.  It looks like this will need to be a chip replacement, I haven't yet found a 14 pin SOIC replacement for the NE5210D

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  2042   Thu Jan 11 13:31:36 2018 awadeMiscLab InfrastructureAnts nesting in PSL lab

There are a large number of ants making a trail from the ATF lab to the PSL lab.  They seem to be heading into a hole next to the lab door.  I just saw a queen ant poke its head out of the hole.  

Ants in the ATF lab are taking their ussual route along the AC conduit.  There are Terro baits laid ever 3-4 meters and they have almost emptied every one. The trails continue to the mechanical plant room accross the hall (room 259ME)

Laying down Terro ant poison now. Will buy more.

Thu Jan 11 13:33:04 2018

Attachment 1: 20180111_antnestforming.jpg
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  2088   Mon Feb 12 20:03:53 2018 awade, CraigMiscLab InfrastructureFlipped circuit breaker at around 8 pm

Flipped circuit breaker at around 8 pm.

I looks like we've overloaded the UPS group one circuit.  I was operating a heat gun off some of the table power and flipped the circuit breaker.  

Unfortunately the lasers were running off this circuit. The whole point of the UPS was to avoid the hard shutdowns. We switching the lasers to group 2 on the UPS so that this doesn't happen again.

  2100   Thu Feb 22 15:15:20 2018 awade, CraigMiscSafetyWater leak in the lab

We have a steady drip of water coming down from the recently updated pipes.  Apparently the pipe is cracked all the way up to the ceiling.

We've shut down the UPS and all the circuits around that corner of the lab.  Facilities people are here looking into the issue. 

There was quite a lot of water pooled around the west side of the optical table. Craig has mopped this up, although it did get under the table legs and under the tiles.  All the electrical stuff under the table was on racks off the ground. Dripping is coming from pipes directly above the rack but it appears that none of it has made it into the rack itself.  We are removing all the very valuable electronics (e.g. marconi and oscilloscopes) and none appear to have water on or around them.

Lasers are shut down.

 

  2103   Fri Feb 23 13:15:22 2018 awadeMiscSafetyWater leak in the lab

Checked the piping again this morning.  The water is just a slow drip now. The facilities people put duct tape around the pipe crack and isolated the source of water on the floor above.  Don't think its safe yet to turn the rack back on, given the proximity of the water and the quality of the patch job. 

I called facilities to find out what the status of the job was and the timelines for fixing.  They didn't have the poly pipe in stock and have reordered. The earliest they can get to starting on the job will be Monday.  The guy responsible is away today.  We should call ext 4969 (Caltech plumbing shop) early on Monday to get an update on expected completion time of the job. Until then we should redirect effort into SURF search, noise budgeting, scatter modeling, PID modeling, FSS sub-noise budget etc.

 

Quote:

We have a steady drip of water coming down from the recently updated pipes.  Apparently the pipe is cracked all the way up to the ceiling.

We've shut down the UPS and all the circuits around that corner of the lab.  Facilities people are here looking into the issue. 

There was quite a lot of water pooled around the west side of the optical table. Craig has mopped this up, although it did get under the table legs and under the tiles.  All the electrical stuff under the table was on racks off the ground. Dripping is coming from pipes directly above the rack but it appears that none of it has made it into the rack itself.  We are removing all the very valuable electronics (e.g. marconi and oscilloscopes) and none appear to have water on or around them.

Lasers are shut down.

 

 

  2106   Mon Feb 26 14:16:38 2018 awadeMiscSafetyWater leak in the lab

I called facilities.  They say with their new purchase approval process, and lead time on parts, that they expect the repair jobs on piping would start early next week.  

There will be a bit of manual alterations to the through hole coming down into the ceiling so we need to do some dust mitigation.  I will order some more cling wrap and salvage some of the plastic sheeting from the last episode.

Quote:

Checked the piping again this morning.  The water is just a slow drip now. The facilities people put duct tape around the pipe crack and isolated the source of water on the floor above.  Don't think its safe yet to turn the rack back on, given the proximity of the water and the quality of the patch job. 

I called facilities to find out what the status of the job was and the timelines for fixing.  They didn't have the poly pipe in stock and have reordered. The earliest they can get to starting on the job will be Monday.  The guy responsible is away today.  We should call ext 4969 (Caltech plumbing shop) early on Monday to get an update on expected completion time of the job. Until then we should redirect effort into SURF search, noise budgeting, scatter modeling, PID modeling, FSS sub-noise budget etc.

 

  2110   Wed Feb 28 11:50:21 2018 awadeMiscSafetyPipe work scheduled for lab Friday March 2nd

The Caltech plumbing shop called to say they will have all the parts they need to start work Friday morning.  There is a bit of masonary work to be done to the down pipe hole.  So there will be some dust.

I have ordered materials from McMaster for wrapping the experiment up again.  I got extra so we will have a cling-wrap-kit® for the WB labs ready to go in the future. I didn't get a tracking recipt, but the order went through around COB on the 26th.  Should be here today or tomorrow.

Quote:

I called facilities.  They say with their new purchase approval process, and lead time on parts, that they expect the repair jobs on piping would start early next week.  

There will be a bit of manual alterations to the through hole coming down into the ceiling so we need to do some dust mitigation.  I will order some more cling wrap and salvage some of the plastic sheeting from the last episode.

 

  2111   Wed Feb 28 13:43:15 2018 awade, CraigMiscSafetyPipe work scheduled for lab Friday March 2nd

The lab is all wrapped up and ready to go.  I'm trying to get in contact with plumbing to see if we can move the job forward to Thursday.  

Edit awade Wed Feb 28 14:58:12 2018: Got throught o Raymond at ext 1252, the job is locked in for Friday morning and can't be moved forward.  Hopefully we can get to cleaning the lab by Friday afternoon and reboot for the weekend.

 

 

Quote:

The Caltech plumbing shop called to say they will have all the parts they need to start work Friday morning.  There is a bit of masonary work to be done to the down pipe hole.  So there will be some dust.

I have ordered materials from McMaster for wrapping the experiment up again.  I got extra so we will have a cling-wrap-kit® for the WB labs ready to go in the future. I didn't get a tracking recipt, but the order went through around COB on the 26th.  Should be here today or tomorrow.

 

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  2113   Fri Mar 2 19:33:14 2018 awadeMiscPurchasesNew Wiha 2.0-7.0 Nm torque control driver

New Torque Driver

I purchased a new torque driver for use in the CTN lab.  It is the Wiha TorqueVario 2.0-7.0 Nm (model 28655), pictured below. This is the highest value driver in their variable torque driver selection with a range that is appropriate for tightening 1/4-20 bolts on the table.  We already have the much lower range Adjustable TorqueVario 15 - 80 In/Oz (model 28501), but this range is only appropriate for very low torque applications like fastening PBS and mirrors. In the future we might like to get a mid-range driver to cover the whole range.

I also purchased a selection of Phillips and flat head driver blades to go with the driver heads because they were relatively cheap. All the Wiha blades are exchangeable between their torque tools, they will likely come in handy for a range of precision applications.

So How Much Should We Torque?

So far I've only tested the new driver qualitatively. 

The range of torques applied by humans in the lab varies widely and there isn't a lot of (good) advice out there on the optimal value.  Over torquing leads to deformation of the table, this can misalign optics in the short term and that then undergo a very slow relaxation over a long period of time.  In the worst cases the table or opto-mechanical components go past their elastic limit. An under tensioned bolt is obviously bad.  Without a strong rigid connection to the table the optic mount may be free to move in a number of lower frequency modes that otherwise wouldn't be allowed (bad).  Rana has recommended an applied torque of ~5-6 pound-inch (6.8-8.1 Nm), this is supposed to be just below the limit of most aluminum and steal plates before they go from elastic to plastic deformation.

Here is an except from LIGOX chat channel from Rana:

Most of the time, it doesn't matter. You can use whatever seems right to you. However, in situations where precision matters, you have to consider what the requirement on the fastening is: e.g. when clamping a 1/4" thick base to an optical table, we use 1/4-20 screws because that's what the table is tapped for. The screw length should be chosen so as to use all the threads in the table.

But, how much torque should be used?

If too much is used, the aluminum base will be deformed so that it is no longer in the elastic regime. Once there is significant plastic deformation, there will be slow mis-alignment of the mount.

Washers increase the total force which can be used, since it reduces the pressure on the soft aluminum given a fixed force. For the usual set of Thorlabs hardware we have the correct torque is ~5-6 ft. lbs [6.8-8.1 Nm]. Similar numbers can be found for other cases by considering what materials are being used.

Initial Qualitative Test

I tested a few different values of torque on the table for a 1/4-20 bolts (with washers) directly on the table in the ATF lab. I used the south table in the ATF lab as many of the tapped holes in the CTN lab have been damaged from over-torquing and contaminants in the treads.  

A dozen 1/4-20 bolts (with washers) were fastened with identical torque values starting at 2 Nm (see second picture). Between each torque cycle I undid the bolt under test with a regular ball driver to get a feel for force used. From their I incremented the applied torque by 0.5 Nm on each tightening cycling working up to 7 Nm. When undoing a bolt there is a kind of a 'crack'. This is the point at which the fastener goes from vertical contact friction to loose thread-only friction.

I found that the 'soft crack' point was 2.0 - 2.5 Nm.  The transition to 'hard crack' (an audible click) occurs at about 3.5 Nm.  However, interestingly, the variability between 3.5 Nm tightened bolts seemed to higher; 3 out of 12 bolts gave a softish crack.  Its likely that the particulars of washer-table-bolt surfaces may change the crack point.  I found that a torque of 4.0 Nm gave a guaranteed hard crack without seeming qualitatively excessive. The transition between regimes was a rapid one and above 4.0 Nm the friction hold was about the same, giving about the same 'crack'.

I found the recommended 6.8-8.0 Nm was very tight.  A value of 7 Nm required a very strong grip on the driver, this is the kind of torque that might only easily be applied using a T-handle driver or a long allen key. A value of 7 Nm seemed unreasonably high compared to what is usually used, this is at the upper range I've seen in various labs. 

My initial recommendation is for 3.5-4.0 Nm tightening of regular bolts for most mounts.  My usual peronsal choice is for a soft crack at around 2.5 Nm.  

Procuring Fixed Value Drivers For General Lab Use

Wiha sells fixed value torque drivers in increments of 0.5 Nm (see Wiha EasyTorque), these fit the standard blades and are reasonably priced. They also sell fixed value Wing Handles that have a compact profile.  We may want to do some scientifically rigorous tests of various post-fork and base-dogclamp combinations to see what the best objective torque value is.

 

 

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  2115   Sun Mar 4 05:22:05 2018 ranaMiscPurchasesTorque spec for optical mounts

The case I was describing is with the BA-1, BA-2, or BA-3 from thorlabs, using a steel (18-8) screw and a SS washer. In this case, you want to go to ~75% before plastic deformation of the aluminum. In this situation, the screw and the base will be elasticly deformed. More tightness will make it plastic and then slowly drift. Less will just give you less stiffness against vibration.

For the case of the 1/4-20 screw with washer in a fork clamp, I expect it can go more, but probably not necessary. To test for drift, we would need an ultra stable Mach-Zender and a long term visibility test, as was done for the stability tests of the Japanese Super Duralumin mounts that Koji has.

Dennis Coyne has a formula to figure out these numbers. I'm going to get to the bottom of this and make it part of this summer's course on Lab Skills.

  2143   Sat Mar 17 14:32:05 2018 StellaMiscElectronics EquipmentPhase Noise for 21.5 MHz Sine Wave

The Phase Detector method was used to measure the phase noise of the 21.5 MHz Sine Wave generated by the RIGOL Waveform Function Generator. Noise measurements were taken using the SR785 across frequencies spanning 0.25 Hz to 102.4 kHz.

Attachment 1: RIGOLPhasenoise_Spectra.pdf
RIGOLPhasenoise_Spectra.pdf
  2146   Mon Mar 19 13:09:43 2018 awadeMiscElectronics EquipmentPhase Noise for 21.5 MHz Sine Wave

Great, it looks like you've got your setup working.

A few things about eloging, though. More information is almost always better. It would be good to add a bit more about your setup so that people know what you actually did and so you can repeat it if you come back in the future to look at your posts.

Maybe you can add another post with a schematic of your experiment labeled with part numbers, frequencies, power levels etc: everything somebody else would need if they were to do the build they same setup. Elog also has the ability to include latex markup which is handy for posting a few key equations.  For example, there are a few Rigol function generators, I find it helpful in the elogs I make to explicitly include part numbers and also hyperlink those labels to the website/datasheet of those components.  You want to actually explain what you did in some detail; some people use dot points, others write full sentences and paragraphs.  The main thing is you include lots of context and useful information about what happened.

With the plot, it looks ok, but you want to increase the font sizes and include units on the y-axis.  I'm not really sure what measurement you made was. It says its a transfer function but it should be in units that make sense like rad/sqrtHz or Hz/sqrtHz. Craig is good at making plots in python maybe have a chat to him about how to make nice plots.

Quote:

The Phase Detector method was used to measure the phase noise of the 21.5 MHz Sine Wave generated by the RIGOL Waveform Function Generator. Noise measurements were taken using the SR785 across frequencies spanning 0.25 Hz to 102.4 kHz.

 

  2231   Sat Sep 8 17:34:54 2018 awadeMiscComputersWS1 CPU fan dead

WS1, the main computer in the PSL lab died last night.  On reboot bios screen says that CPU fan died.  

I opened the computer up and had a look.  Bearings on main CPU fan were a bit stiff.  I wiggled them a bit and it now spins, with some noise, when booted.  

I'll order a replacement CPU fan KDE1209PTVX 12V, 7.0 W and replace pronto.

Main CPU fan
Main CPU fan, bearings nearing end of life.

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Also there was no backup of this computer.  Almost all the stuff is kept in Git version control, but we should get these computers back on scripted backups.

 

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Edit Sat Sep 8 18:28:19 2018: Rebooted and restarted frequency counter. Beat note has drifted off to 750 MHz.  Will take a while to bring it back in.

Fan has been reordered, will arive Friday next week.

  2234   Mon Sep 17 14:08:56 2018 awadeMiscComputersWS1 CPU fan replaced

Found that WS1 had died again.  CPU fan seized up again.

Replaced and computer restarted fine. WS1 up and running normally.

Quote:

WS1, the main computer in the PSL lab died last night.  On reboot bios screen says that CPU fan died.  

I opened the computer up and had a look.  Bearings on main CPU fan were a bit stiff.  I wiggled them a bit and it now spins, with some noise, when booted.  

I'll order a replacement CPU fan KDE1209PTVX 12V, 7.0 W and replace pronto.

Main CPU fan
Main CPU fan, bearings nearing end of life.

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Also there was no backup of this computer.  Almost all the stuff is kept in Git version control, but we should get these computers back on scripted backups.

 

---

Edit Sat Sep 8 18:28:19 2018: Rebooted and restarted frequency counter. Beat note has drifted off to 750 MHz.  Will take a while to bring it back in.

Fan has been reordered, will arive Friday next week.

 

  2256   Wed Nov 21 19:33:23 2018 awadeMiscElectronics EquipmentSR785 (SN46950)

The main SR785 (Serial number 46950) has a dead screen. 

I power cycled the unit and also checked that the screen brightness wasn't set to zero.

Getting it serviced at Stanford Research Systems can be expensive.  In the past they have just sent the CRT and it is easy to replace ourselves.  I'll put in a request for a quote and orgainize for the screen to be replaced later this week.

  2262   Fri Dec 7 11:26:30 2018 awadeMiscDAQFrame builder back up

Framebuilder has been down for months now.  It looks like I've been able to get it up and going again albeit with the same issues of drifting clock from before.

I restarted the TCS lab framebuild computer (fb4) that is supposed to be recording all our PSL lab channels.  It seems that the daqd process was hung on something. After poking around a bit I found that a large proportion of channels have been renamed, maybe requests to dead channels was overwhelming it.  I used Craig's python channelFramebuilderConfigFileCreator.py script (see PSL:2133) to regenerate all channels into a .ini file used by cds, copied the output to them to /opt/rtcds/caltech/c4/chans/daq/C3CTN.ini and restarted.  

Framebuild is now back and recording all channels (except modecleaner channels) with a UTC time that is 2h 20 m too slow.  Otherwise we are now collecting data that will be useful in assesing goodness of vacuum can temperature control.

To fix the time drift issues we need to get GPS stablized timing waveform into the daq

Todo list:

  • Run 10 MHz backlink from cryo lab to TCS lab
  • Aquire function generator to generate 65kHz (32 KHz?) waveform to feed into framebuilder
  • Electronics hardware to connect into ADC in fb4
  • Configure fb4 to stablize to GPS standard

Someone else needs to do this.  Maybe a secondary project for Gupta.

 

  2383   Wed Aug 7 14:42:58 2019 Nathan HollandMiscElectronics EquipmentBorrowed SRS DB64.

I have borrowed the SRS DB64. It is in QIL.

  2400   Tue Aug 27 18:53:15 2019 ranaMiscFSSup to date schematics

I'm skeptical of your FSS changes over the past year. Can you please link to the DCC entry that has the actual, real, as-built, as-modified FSS schematics? i.e. including all changes no matter how minor.

  2407   Fri Aug 30 18:25:31 2019 anchalMiscFSSup to date schematics

All details regarding TTFSS boxes present in CTN has been updated at this page in ATFWiki

https://nodus.ligo.caltech.edu:30889/ATFWiki/doku.php?id=main:experiments:psl:ttfss

I have added fields of who made the changes, on which box and on which board to make this change log more readable. These fields should be followed from now on.

Relevant circuit schematics, photos and zero models are kept in ctn_electroncs/TTFSSzeroCTN repo to keep a version history of changes as well. This should be updated everytime any change is made to the boxes from now on.

Note: The current updates were made by using Andrew's change log and verifying that no other changes have been mentioned in our elog history other than the change log. However, if the real circuit has any changes which people did not log, then they are not present in these schematics or model. These, if they exist, will be added as soon as we find them.

Quote:

I'm skeptical of your FSS changes over the past year. Can you please link to the DCC entry that has the actual, real, as-built, as-modified FSS schematics? i.e. including all changes no matter how minor.

 

  2475   Sat Nov 9 13:46:08 2019 shrutiMiscElectronics EquipmentBorrowed

I've borrowed a Marconi VCO, a mini-circuits LPF and mixer from the CTN lab for use at the WB EEshop.


AG Mon Dec 30 10:24:28 2019 : Has been returned to CTN now.

  2581   Mon Jun 8 18:19:46 2020 anchalMiscOtherDAMOP Conference Brief Summary

I've made a brief summary of the talks and topics I saw in DAMOP 2020 conference which happened virtually last week. Here is the link:

https://docs.google.com/document/d/1qsOVHgfq-Fsxd72qOwUWAq6JO2XRvewyd0fMzVfbHtk/edit?usp=sharing

You would need to sign in using your Caltech email address (jdoe@caltech.edu) to access the file.

  2590   Wed Sep 23 00:21:02 2020 aaronMiscEquipment loanHP 8560E SA to Cryo

I entered CTN just before (Wed Sep 23 00:22:11 2020 ) to borrow a spectrum analyzer, which I took to Cryo. Wore shoe covers, goggles. Sanitized goggles and door after.

  2597   Tue Nov 24 16:23:26 2020 PacoMiscEquipment loanbroadband EOM

Borrowed 1 (new focus) broadband EOM from CTN for temporary use in Crackle (2 um OPO experiment)

  2604   Wed Dec 9 18:13:12 2020 PacoMiscEquipment loannew focus 1811

Borrowed two broadband PDs (new focus 1811) and one power supply unit (new focus 0901) from CTN into Crackle.

  2610   Wed Aug 18 11:12:47 2021 aaronMiscElectronics EquipmentSR560 to cryo

I borrowed one two unused SR560 from CTN to Cryo. The first one had periodic noise at 100 Hz (operated in low noise AC coupled mode, G=100, with a 30 kHz lowpass).

  59   Mon Feb 8 18:12:46 2010 FrankNotesAOMimpedance measurements

measured the impedance from 70MHz to 90MHz for three different AOMs we had in the lab - two Isomet 1205C-843 and one Crystal Technologies 3080-194.
It turns out that the tiny power modulation on top of the big power modulation and pointing effects is related to some resonance effects in the AOM.
The Isomet AOMs show both this feature, the other one not. So we decided to install the one from Crystal Technology...

AOM-impedance_2010-02-08.png

  178   Tue Jun 29 11:15:40 2010 FrankNotesFoamfoam physical properties

physical properties for the new yellow foam used for insulation (Certifoam 25):

thermal conductivity k (Btu/h ft2 °F):
@ 75° F mean :  0.200
6-Month Aged Values @ 75° F mean : 0.192
fresh (As Manufactured) : 0.11

assuming ~0.2 Btu/h ft2 °F the calculated k-value in Si units is 1.136 W/m2-K which matches the R-value given below

 

density  : 29 kg/m3

 

thermal resistance (R-value, 1in thickness)  : 0.88 K-m2/W

The conversion between SI and US units of R-value is 1 h·ft²·°F/Btu = 0.176110 K·m²/W, or 1 K·m²/W = 5.678263 h·ft²·°F/Btu.

 

 English Unit

Quantity

Multiply by

Factor

Metric Unit

inch

1

25.4

25.40

mm

foot

1

0.3048

0.30

m

in2

1

645.16

645.16

mm2

ft2

1

0.09290304

0.09

m2

ft3/min

1

0.0004719

0.00

m3/s

BTU/hr

1

0.2930711

0.29

W

BTU/hr-ft-F

1

1.729577

1.73

W/m-K

BTU/hr-ft2

1

3.1546

3.15

W/m2

BTU/hr-ft2-F

1

5.67826

5.68

W/m2-K

BTU-in/hr-ft2-F

1

0.144228

0.14

W/m-K

F-ft2-hr/BTU-in

1

6.9333466

6.93

m-K/W

F-ft2-hr/BTU

1

0.176109

0.18

m2-K/W

lbf/ft3

1

16.01846

16.02

kg/m3

lbf/ft2

1

47.88026

47.88

Pa

mph

1

0.44704

0.45

m/s

 

 


  180   Tue Jun 29 11:53:41 2010 FrankNotesNoiseBudgetlist of emissivity coefficients

source: http://www.engineeringtoolbox.com/emissivity-coefficients-d_447.html

 

Surface Material Emissivity Coefficient
- ε -
Alloy 24ST Polished 0.9
Alumina, Flame sprayed 0.8
Aluminum Commercial sheet 0.09
Aluminum Foil 0.04
Aluminum Commercial Sheet 0.09
Aluminum Heavily Oxidized 0.2 - 0.31
Aluminum Highly Polished 0. 039 - 0.057
Aluminum Anodized 0.77
Aluminum Rough 0.07
Aluminum paint  0.27 - 0.67
Antimony, polished 0.28 - 0.31
Asbestos board  0.96
Asbestos paper 0.93 - 0.945
Asphalt 0.93
Basalt 0.72
Beryllium 0.18
Beryllium, Anodized 0.9
Bismuth, bright 0.34
Black Body Matt 1.00
Black lacquer on iron 0.875
Black Parson Optical 0.95
Black Silicone Paint 0.93
Black Epoxy Paint 0.89
Black Enamel Paint 0.80
Brass Dull Plate 0.22
Brass Rolled Plate Natural Surface 0.06
Brass Polished 0.03
Brass Oxidized 600oC 0.6
Brick, red rough 0.93
Brick, fireclay 0.75
Cadmium 0.02
Carbon, not oxidized 0.81
Carbon filament 0.77
Carbon pressed filled surface 0.98
Cast Iron, newly turned 0.44
Cast Iron, turned and heated 0.60 - 0.70
Chromium polished 0.08 - 0.36
Concrete 0.85
Concrete, rough 0.94
Concrete tiles 0.63
Cotton Cloth 0.77
Copper electroplated 0.03
Copper heated and covered with thick oxide layer 0.78
Copper Polished 0.023 - 0.052
Copper Nickel Alloy, polished 0.059
Glass smooth 0.92 - 0.94
Glass, pyrex 0.85 - 0.95
Gold pure and highly polished 0.018 - 0.035
Granite 0.45
Gypsum 0.85
Ice 0.97
Inconel X Oxidized 0.71
Iron polished 0.14 - 0.38
Iron, plate rusted red 0.61
Iron, dark gray surface 0.31
Iron, rough ingot 0.87 - 0.95
Lampblack paint 0.96
Lead pure unoxidized 0.057 - 0.075
Lead Oxidized 0.43
Lime wash 0.91
Magnesium Oxide 0.20 - 0.55
Magnesium Polished 0.07 - 0.13
Marble White 0.95
Mercury liquid 0.1
Mild Steel 0.20 - 0.32
Molybdenum polished 0.05 - 0.18
Nickel, elctroplated 0.03
Nickel, polished 0.072
Nickel, oxidized 0.59 - 0.86
Nichrome wire, bright 0.65 - 0.79
Oak, planed 0.89
Oil paints, all colors 0.92 - 0.96
Paper offset 0.55
Plaster 0.98
Platinum, polished plate 0.054 - 0.104
Porcelain, glazed 0.92
Paint 0.96
Paper 0.93
Plaster, rough 0.91
Plastics 0.91
Quarts glass 0.93
Roofing paper 0.91
Rubber, hard glossy plate 0.94
Rubber Nat Hard 0.91
Rubber Nat Soft 0.86
Sand 0.76
Sawdust 0.75
Silicon Carbide 0.83 - 0.96
Silver Polished 0.02 - 0.03
Steel Oxidized 0.79
Steel Polished 0.07
Stainless Steel, weathered 0.85
Stainless Steel, polished 0.075
Stainless Steel, type 301 0.54 - 0.63
Steel Galvanized Old 0.88
Steel Galvanized New 0.23
Tile 0.97
Tin unoxidized 0.04
Titanium polished 0.19
Tungsten polished 0.04
Tungsten aged filament 0.032 - 0.35
Water 0.95 - 0.963
Wood oak 0.91
Wrought Iron 0.94
  181   Tue Jun 29 13:22:51 2010 JenneNotesNoiseBudgetlist of emissivity coefficients

Quote:
Surface Material Emissivity Coefficient
- ε -

 Source?  This is probably handy to have around, but is it from someone who actually measures these things, or is it from a random number generator with the output stuck in some table on wikipedia? 

  182   Tue Jun 29 14:20:04 2010 taracNotesLaserCalibration [Hz/V] for modulating signal (PMC and laser)

1) DC ext channel on PMC servo:          32.82 MHz/ V

2) Fast channel on the laser controller:   3.07 MHz/V ( Our Fn generator can provide +/- 20V -> 60 MHz span, this won't let us see all three peaks of the error signal from RefCav which has 35.5x2 = 71 MHz span)

3) Temperature actuator on the laser control:  220 MHz/V.  (1FSR= 714 MHz, 2x cavity length = 0.42m)

 

This measurement is done by scanning the laser frequency (1 and 3)or cavity length (2) and see the error signal.

The two sidebands are 43 MHz apart , divided that by the corresponding Voltage difference of the sidebands to get the calibration. For Temperature actuator we see use the PMC's FSR instead of the sidebands for better accuracy.

  183   Tue Jun 29 14:22:31 2010 FrankNotesNoiseBudgetsummary of emissivity coefficients for refcav experiment

emissivity coefficients - ε -  (300K)

Quartz, Rough, Fused  :  0.93
Stainless Steel, sandblasted : 0.38
Stainless steel: type 18-8, sandblasted
: 0.44
Stainless Steel, polished : 0.075
Aluminum Foil, shiny side : 0.03
Electroplated Gold : 0.03

Gold: plated on stainless steel and polished : 0.028

  184   Tue Jun 29 14:59:52 2010 FrankNotesNoiseBudgetbetter list of emissivity coefficients

source : http://www.omega.com/temperature/z/pdf/z088-089.pdf

emission_coefficients.pdf

  185   Tue Jun 29 15:13:26 2010 FrankNotesRefCavrefcav physical properties

refcav physical properties from CAD model for heat capacity calculation

volume (incl. mirrors, center bore, venting hole) : 23.47900 (in^3) = 0.000384751876 m^3

mass (incl. mirrors, center bore, venting hole) : 1.86900 pounds = 0.84776414 kilograms

 

  186   Tue Jun 29 17:57:40 2010 taracNotesPMCcoupling eff vs Temperature

We had a problem with power coupling efficiency to the PMC.  Sometime it changes from 80% to 40% or less.

When the temperature of the NPRO is varied by a voltage calibrator @ slow actuator input of the laser controller,

at certain T(V), the coupling efficiency drops from 80% to 40% or less. This might be mode hopping.  However, the transmitted beam power still oscillates ,

and one can see the beam spot pulsating on the screen. I thought it might be mode hopping too, but after changing T, the fluctuation of the power has not gone, there is some suppression though. So it might be the servo. I'll check the TF of the servo and compare it with the schematic, D980352-B-1.

  187   Tue Jun 29 23:56:38 2010 taracNotesPMCPMC servo debugging

 I was going to check the TF on each stage of PMC's servo.

Unfortunately, I couldn't find the floppy disc drive, so I slide the sliders (gain, RF power) around. When I add more RF power (from 1V to 7V) to 21.5 MHz EOM, the oscilaltion subsides*.

(*5 mins later I came back to turn down the RF power to 1 V again, and the beam was perfectly locked for a few minutes before fluctuated again)

It's not a long term solution, but I note this for further debugging.

One thing about the gain, I see the TF of the whole PMC servo, when I increase the common gain from 0 to ~8 dB, the magnitude of the TF gets higher. If I increase more gain to ~ 10dB or something, the magnitude goes down . So there might be sth wrong about the opamp that controls the gain.

 

ELOG V3.1.3-