Not dead. It just had a HT fault. You can tell by reading the front panel. Cycling the power usually fixes this.

I talked with Rolf, and asked if we were using Megatron for IO.  The gist boiled down to we (the 40m) needed to use it for something, so yes, use it for the IO computer.  In regards to the other end station computer, he said he just needed a couple of days to make sure it doesn't have anything on it they need and to free it up.

I had a chat with Jay where he explained exactly what boards and cables we need.  Adapter boards are 95% of the way there.  I'll be stopping by this afternoon to collect the last few I need (my error this morning, not Jays).  However it looks like we're woefully short on cables and we'll have to make them. I also acquired 2 D080281 (Dsub 44 x2 to SCSI).

For each 2 Pentek DACs plus a 110B, you need 1 DAC adapter board (D080303 with 2 connectors for IDC40 and a SCSI).  You also need a D080281 to plug onto the back of the Sander box (going to the 110Bs) to convert the D-sub 44 pins to SCSI.

LSC will need none, SUS will need 3, IO will need 1, and the ends will need 1 each.  We have a total of 6, we're set on D080303s.  We have 3 110Bs, so we need one more D080281 (Dsub44 to SCSI).  I'll get that this afternoon.

For each XVME220, we'll need one D080478 binary adapter.  We have 8 XVME220s, and we have 8 boards, so we're set on D08478s.

For the ends, there's a special ADC to DB44/37 adapter, which we only have 1 one of.  I need to get them to make 1 more of these boxes.

We have 1 ADC to DB37 adapter, of which we'll need  1 more of as well, one for IO and one for SUS. 

However, for each Pentek ADC, we need a IDC40 to DB37 cable.  For each Pentek DAC we need an IDC40 to IDC40 cable.  We need a SCSI cable for each 110B.  I believe the current XVME220 cables plug directly in the BIO adapter boxes, so those are set.

So we need to make or acquire 11 IDC40 to DB37 cables, 7 IDC40 to IDC40 cables, and 3 SCSI cables.

Summary Needed:

1 ADC to DB44/37 for the End (D080397)

1 ADC adapter (D080302)

1 Dsub44 to SCSI (D080291)

11 IDC40 to DB37 cables

7 IDC40 to IDC40 calbes

3 SCSI cables

PLUS from before:

3 IO Chassis (2 Dolphin, 1 Small)

1 1U computer (8 core for end)

Router/2 50+m ethernet for DAQ

I picked up the ribbon cable connectors from Jay.  It looks like we'll have to make the new cables for connecting the ADCs/DACs myself (or maybe with some help).  We should be able to make enough ribbon cables for use now.  However,  I'm adding "Make nice shielded cables" to my long term to do list.

I pointed out the 2 missing adapter boxes we need to Jay.  He has the parts (I saw them) and will try to get someone to put it together in the next day or so.  I also picked up 2 more D080281 (DB44 to SCSI), giving us enough of those.

I once again asked Jay for an update on IO chassis, and expressed concern that without them the CDS effort can't really go forward, and that we really need this to come together ASAP.  He said they still need to make 3 new ones for us.

So we're still waiting on a computer, 3 IO chassis, router + ethernet.

MOPA is back onliine.  Rana found that the fuse in the AC power connector's fuse had blown.  This was evident by smelling all of the inputs and outputs of the MOPA controller. The power cord we were using for this was only rated for 10A and therefore was a safety hazard. The fuse should be rated to blow before the power cord catches on fire. The power cord end was slightly melted. I don't know why it hadn't failed in the last 12 years, but I guess the MOPA was drawing a lot of extra current for the DTEC or something due to the high temperature of the head.

We got some new fuses from Todd @ Downs. 

The ones we got however were fast-blow, and that's what we want  The fuses are 10A, 250V.  The fuses are ~.08 inches long, 0.2 inches in diameter. 

The folding crane was fixed and tested this morning by the NNN rigging company. Pictures will be posted by Steve in the morning.

Afterwards, the ITM-east door was installed, jam-nuts checked. No high voltage was on for the in-vac PZTs.

The annulus spaces were roughed down to 350mTorr by Roughing Pump RP1. For this operation, we removed the low flow valve from the RP1 line.

After the spaces came down to ~400 mTorr, we closed their individual valves.

Warning: The VABSSC1 and VABSSC0 valves are incorrect and misleadingly drawn on the Vacuum overview screen.

We then:

1. Closed V6 (valve between RP1 and the annulus line).
2. Turned off RP1 from the MEDM screen.
3. Installed the soft -starting butterfly valve.
4. Turned on RP1.
5. Opened V3.
6. Closed VV1 (at the last minute - this is a vent valve and must be checked before each pumpdown)
7. and pumpdown was started with a 3/4 turn opening of manual valve RV1.

Our idea is to have a much slower pumpdown this time than the last time when we had a hurricane kick up the dust. Looks like it worked, but next time we should do only 1/2 turn.

A little D-sub terminator was put on the Gur1 input to the Guralp box, to check again the noise level of the box.

The pumpdown started at 4 PM (2300 UTC). At 10 PM, we (Jenne, Jan, and I) opened up the RV1 valve to full open. That's the second inflection point in the plot.

As per Steve's instructions, at 12:43 AM, I used the following steps to stop the pumpdown until the morning:

1. Close RV1 using the 'steering-wheel' wrench.
2. Close V3.
3. Turn OFF RP1.
4. Disconnect RP1 hose at the plastic disconnect attached to the slow-start throttle valve.

Summary of this Week's Activities:

6/23: LIGO Safety Tour; Simulink Controls Tutorial

6/24: Simulink Diagram for Feedback Loop; Constructed Pendulum Transfer Function; Discussion with Dr. Weinstein

6/25: Prepare for pump-down of vacuum chamber; crane broken due to locking failure; worked through COMSOL tutorials

6/28: Ran through Python Tutorials; Began learning about Terminal

6/29: Wrote Progress Report 1 First Draft

6/30: Began editing Progress Report 1

Wednesday Morning E-log :

Most of the time through this week, i was working towards making the simulink model work.

It involved learning simulink functions better, and also improving on the knowledge of control theory in general, and control theory of our system.

1. Thusrday : found tfs for the feedback loop. and tried many different filters and gains to stabilize the system (using the transient response of the system). - not through

2. Friday : decided to use error response and nullify the steady state error instead of looking at convergence of output. tried many other filter functions for that.

Rana then showed me his files for WFS.

3. Sunday - played with rana's files, learnt how to club simluink with matlab, and also about how to plot tfs using bode plots in matlab.

4. Monday : Read about state-space models, and also how to linearize in matlab. done with the latter, but the former still needs deeper understanding.

read ray-optics theory to calculate the geometric sensing matrix.

It first requires to calculate the eigen mode of the cavity with tilted mirrors. this eigen mode is needed to be found out using ray-optics transfer matrices for the optics involved  . figured out  matrices for the tilted plane mirrors, and am working on computing the same for MC2.

5. Tuesday : went to Universal Studios , Hollywood :P

6. Wednesday (today) : Writing the report to be submitted to SFP.

I spent this morning populating the SUS IO Chassis and getting it ready for installation into the 1Y4 rack.  I discovered I'm lacking the internal cables to connect the ADC/DAC boards to the AdL adapter boards that also go in the chassis (D0902006 and D0902496).  I'm not sure where Alex got the cables he used for the end IO chassis he had put in.  I'll be going to Downs after the meeting today either to get cables or parts for cables, and get the SUS chassis wired up fully.

I'd also like to confirm with Alex that the OSS-MAX-EXP-ELB-C board that goes in the IO chassis matches the host interface board that goes in the computer (OSS-HIB2-PE1x4-1x4 Re-driver HIB, since we spent half a day the last time we installed an IO chassis determining that one of the pair was bad or didn't match.

The SUS chassis has been populated in the following way:

Treton Board

Slot 1 ADC PMC66-16AI6455A-64-50M

Slot 2 DAC PMC66-16AO16-16-F0-OF 

Slot 3-6 BO Contec DIO-1616L-PE Isolated Digital IO board

Slot 7 ADC PMC66-16AI6455A-64-50M

Slot 8-9 DAC PMC66-16AO16-16-F0-OF 

Back  Board

Slot 1 ADC adapter D0902006

Slot 2 DAC adapter D0902496-v1

Slot 7 ADC adapter D0902006

Slot 8-9 DAC adapter D0902496-v1

Weekly Project Update:

We are studying Haixing's circuit diagram for the quadrant maglev control circuit.  We have analyzed several of the sub-circuits and plotted transfer functions for these in MatLab.  To check the circuit, we will compare the calculated transfer functions with those obtained from the HP control systems analyzer.

To learn how to use the control systems analyzer, we are reading App Note 243 as well as an online manual (477 pages in the first volume).  We are beginning with a simple test circuit, and are comparing its measured frequencyresponse with calculated transfer functions.  We currently have obtained a response graph beginning at 100 Hz (which we have not yet figured out how to print), and we are planning to investigate behavior at lower frequencies.

We also have been continuing our reading on control systems after a failed attempt at magnetic levitation. 

This week I have completed following tasks:

1. Worked out the analytical expressions for the amount of power of the DC and oscillatory part going into the camera.

2. Realigned the He-Ne PhaseCam setup as we had to replace the first steering mirror after the laser with a silvered mirror ( one without a dielectric coating for 1064 nm).

3. Gone through the code written by a previous surfer (Zach Cummings).

4. Read the paper 'Real-time phase-front detector for heterodyne interferometers'- F. Cervantes et. el. where they talk about constructing a phase detector for LISA pathfinder mission. One interesting fact I found was that, they used InGaAs chip for their CCD Cam which has a amazing QE of 80% @ 1064 nm. Unfortunately, the one we are using (Micro MT9V022 CMOS) has only ~5% QE for 1064 nm and 50% for 633 nm. One top of it MT9V022 has a built-in infra-red filter infront of it to make it more insenstive to 1064. In such limitations, we may have to find a work-around for this issue. Any idea?

5. Read about the EOM and AOM and their vibrating (!) way to add on and alter the incident light on them. (Source: Intro to Optical Electronics-Yariv)

One task that we couldn't accomplish even though I planned on doing is:

1. Move,if possible, to the Nd:YAG setup.

Task for this week:

1. Produce breathtaking calibration of the camera at He-Ne setup.

2. Read 'Fringe Analysis'-Y.Surrel and 'Phase Lock Technique'-Gardner.

3. Modify the phasecam code.

4. Produce an alternate triggerbox using diodes instead of Op-Amp as op-amp is suspected to fail at some point driving the camera due to impedance mismatch.

5. Answer Koji's question at Aidan's ELOG .

I moved the Guralp box's input terminator from Gur1 to Gur2 a minute or so ago to check the other channels.

 Atm 2 is showing the butterfly valve that closes down down the orifice at higher pressure to slow down the pumping speed.

 See elog entry #2573

Now that the MC is back up and running, I put the Guralp seismometers at the ends of the mode cleaner.  Gur1 is near MC2, and Gur2 is near MC1 (yes, it seems backwards....that's how the cable lengths work).  Also, the set of 3 MC2 accelerometers are in place under MC2.  I can't find the black cube for the other set of accelerometers, so there aren't any around MC1/3. 

40m SURFs Razib Obaid, Nancy Aggarwal, Unknown Bearded SMURF, Megan Daily, Gopal Nataraj, Katharine Larson and Sharmila Dhevi received 40m specific safety training on June 23, 2010.

In order to identify the output adapter of the BNC patch panel used for about 20 PEM channels, I had to disconnect its power and remove the back panel.  Channels coming into that panel (seismometers and so forth) was out from 1:36 to 1:56 pm.

I did a quick check of some of the channels and it looks like its working again after putting it all back together.

Kevin sent me an email with top secret info on where one of the other accelerometer cubes was hiding (it was with his shaker setup on the south side of the SP table), so I took it and put the 3 MC1 accelerometers in their 3-axis configuration. 

Also, I changed the orientation of both sets of 3 axis accelerometers to reflect a Right Handed configuration, to go along with the new and improved IFO configuration.  Previously (including last night), the MC2 accelerometers were together in a Left Handed configuration.

Thanks to Steve's work on some L brackets, and Kiwamu's lifting help, we now have a new SUS IO chassis in the new 1X4 rack (formerly the 1Y4 rack), just below the new SUS and LSC computers.  I have decided to call the sus machine, c1sus, and give it IP address 192.168.113.85.  We also put in a host interface adapter, OSS-HIB2-PE1x4-1x4 Re-driver HIB, which connects the computer to the IO chassis.

The IP was added to the linux1 name server.  However, the computer itself has not been configured yet.  I'm hoping to come in for an hour or two tomorrow and get the computer hooked up to a monitor and keyboard and get its network connection working, mount /cvs/cds and get some basic RCG code running.

We also ran ethernet cables for the SUS machine to the router in 1X6 (formerly 1Y6) as well as a cable for megatron from 1X3 (formerly 1Y3) to the router, in anticipation of that move next week.

During the day, I realized we needed 2 more ADCs, one of which I got from Jay immediately.  This is for two 110Bs and 4 Pentek ADCs.  However, there's a 3rd 110B connected to c0dcu1 which goes to a BNC patch panel.  Original Jay thought we would merge that into 4 pin lemo style into the 2nd 110B associated with the sus front ends.  We've decided to get a another ADC and adapter.  That will have to be ordered, and generally take 6-8 weeks.  However, it may be possible to "borrow" one from another project until that comes in to "replace" it.  This will leave us with our BNC patch panel and not force me to convert over 20 cables.

I also discovered we need one Contec DIO-1616L-PE Isolated Digital IO board for each Chassis, which I wasn't completely aware of.  This is used to control the ADCs/DACs adapter boards in the chassis.  It means we need still need to put a Binary Output board in the c1iscex chassis.  Hopefully the chassis as they come in come from Downs continue to come with the Contec DIO-1616L-PE boards (they have so far).

The current loadout of the SUS chassis is as follows:

Treton Board

Far left slot, when looking from the front has the OSS-MAX-EXP-ELB-C board, used to communicate with the c1sus computer.

Slot 1 ADC PMC66-16AI6455A-64-50M

Slot 2 DAC PMC66-16AO16-16-F0-OF 

Slot 3-6 BO Contec DIO-32L-PE Isolated Digital Output board

Slot 7 ADC PMC66-16AI6455A-64-50M

Slot 8-9 DAC PMC66-16AO16-16-F0-OF 

Slot 10-11 ADC PMC66-16AI6455A-64-50M

Slot 12 Contect DIO-1616L-PE Isolated Digital IO board

Back  Board

Slot 1 ADC adapter D0902006

Slot 2 DAC adapter D0902496-v1

Slot 7 ADC adapter D0902006

Slot 8-9 DAC adapter D0902496-v1

Slot 10-11 ADC adapter D0902006

Kiwamu and I went through and looked at the spare channels available near the PSL table and at the ends.

First, I noticed I need another 4 DB37 ADC adapter box, since there's 3 Pentek ADCs there, which I don't think Jay realized.

PSL Green Locking

Anyways, in the IOO chassis that will put in, for the ADC we have a spare 8 channels which comes in the DB37 format.  So one option, is build a 8 BNC converter, that plugs into that box.

The other option, is build 4-pin Lemo connectors and go in through the Sander box which currently goes to the 110B ADC, which has some spare channels.

For DAC at the PSL, the IOO chassis will have 8 spare channel DAC channels since there's only 1 Pentek DAC.  This would be in a IDC40 cable format, since thats what the blue DAC adapter box takes.  A 8 channel DAC box to 40 pin IDC would need to be built.

End Green Locking

The ends have 8 spare DAC channels, again 40 pin IDC cable.   A box similar to the 8 channel DAC box for the PSL would need to be built.

The ends also have spare 4-pin Lemo capacity.  It looked like there were 10 channels or so still unused.  So lemo connections would need to be made.  There doesn't appear to be any spare 37 DB connectors on the adapter box available, so lemo via the Sander box is the only way.

Notes

Joe needs to provide Kiwamu with cabling pin outs.

If Kiwamu makes a couple spares of the 8 BNC to 37DB connector boards, there's a spare 37DB ADC input in the SUS machine we could use up, providing 8 more channels for test use.

I connected a monitor and keyboard to the new c1sus machine and discovered its not running RTL linux.  I changed the root password to the usual, however, without help from Alex I don't know where to get the right version or how to install it, since it doesn't seem to have an obvious CD rom drive or the like.  Hopefully Tuesday I can get Alex to come over and help with the setup of it, and the other 1-2 IO chassis.

I went to talk to Rolf and Jay this morning.  I asked Rolf if a chassis was available, so he went over and disconnected one of his test stand chassis and gave it to me.  It comes with a Contect DIO-1616L-PE Isolated Digital IO board and an OSS-MAX-EXP-ELB-C, which is a host interface board.  The OSS board means it has to go into the south end station.  There's a very short maximum cable length associated with that style, and the LSC and IOO chassis will be further than that from their computers (we have dolphin connectors on optical fiber for those connections).

I also asked Jay for another 4 port 37 d-sub ADC blue and gold adapter box, and he gave me the pieces.  While over there, I took 2 flat back panels and punched them with approriate holes for the scsi connectors that I need to put in them.  I still need to drill 4 holes in two chassis to mount the boards, and then a bit of screwing.  Shouldn't take more than an hour to put them both together.  At that point, we should have all the adapter boxes necessary for the base design.  We still need some stuff for the green locking, as noted on Friday.

Major hardware still needed:

2 Dolphin style IO chassis

1 computer for south end front end

We rebooted c1iovme because the lines stopped responding to inputs on C1:I00-MC_DRUM1. This fixed the problem.

I talked to Alex, and he explained the steps necessary to get the real time linux kernel installed.  It basically went like copy the files from c1iscex (the one he installed last month) in the directory /opt/rtlidk-2.2 to the c1sus locally.  Then go into rtlinux_kernel_2_6, and run make and make install (or something like that - need to look at the make file).  Then edit the grub loader file to look like the one on c1iscex (located at /boot/grub/menu.lst).

This will then hopefully let us try out the RCG code on c1sus and see if it works.

[Jenne, Kyung Ha]

We successfully suspended the 4 eddy current dampers for the first Tip Tilt.  We had some lessons learned, including how to carefully get an allen wrench in between the dampers to do up some of the screws, and how to be careful not to bend the wire while tightening the screws.  More tomorrow...

Weekly Update:

Last Weds-Thurs, we wrote and edited our progress reports.

Tuesday (and Weds morning):  Continued circuit analysis of Haixing's circuit and plotting transfer functions (almost have one for entire circuit).  Hooked up OSEM and circuit to power supply, but the LED didn't appear to light up in IR.  Now we are going to hook the OSEM directly to the power supply, sans circuit, to see if the problem is with the circuit or OSEM.

Summary of this Week's Activities:

6/30: 2nd and 3rd drafts of Progress Report

7/1: 4th draft and final drafts of Progress Report; submitted to SFP

7/5: Began working through busbar COMSOL example

7/6: LIGO meeting and lecture; meeting with Koji and Steve to find drawing of stacks; read through Giaime's thesis, Chapter 2 as well as two other relevant papers.

7/7: Continued working on busbar in COMSOL; should finish this as well as get good headway on stack design by the end of the day.

I have completed the following tasks:

1. Find a simplified calibration of the exposure time for the current He-Ne setup. Basically, I triggered the camera to take 20 snapshots with a 20 Hz driving signal at different exposure time beginning from 100 us (microsecond) upto 4000 us with an increment of 200 us.

    Result: The current power allows the camera to have an exposure time of ~500 us before the DC level begans to saturate.

2. Aidan and I did some alignment and connected the AOM and corrected the driving frequency of its PZT to 40 Mhz(which apparently was disconnected which in turn gets the credit of NO beat signal for me until Tuesday 07/06/2010 5:30 PST) .

    Result: I got the beat signal of 1 Hz and 5 Hz. Image follows (the colormap shows the power in arbitrary units).

3. Finished writing my Progress Report 1 .

Wednesday after the meeting - Started report, learnt mode cleaner locking from Kiwamu and Rana, saw how to move optics on the tables with Rana and kiwamu.

Thursday - Made the report

Tuesday - report.

Today - am trying locking the MC with kiwamu's help to see the WFS signals and also to start characterizing the QPD.

The 1 Ton yellow crane support beam jammed up at Friday morning, June 25.

The 40m vertex crane has a folding I-beam support to reach targeted areas. The rotating I-beam is 8 ft long. The folding extension arm gives you another 4 ft.

The 12 ft full reach can be achieved by a straightening of the 4 ft piece. There is a spring loaded latch on the top of the I-beam that locks down when the two I-beams align.

This lock joins the two beams into one rigid support beam for the jib trolley to travel.  The position of this latch is visible when standing below, albeit not very well.

To be safe it is essential that this latch is locked down fully before a load is put on the crane.

We were preparing to pump down the 40m vacuum system on Friday morning. The straight alignment of the 8 and 4 ft piece made us believe that

the support beams were locked. In reality, the latch was not locked down. The jib trolley was driven to the end of the 12 ft I-beam. The 200 lbs ITM-east door was lifted

when the 4 ft section folded 50 degrees around the pivot point. This load of door + jib-trolley + 4 ft I-beam made the support beam sag about 6 inches

The door was removed from the jib hoist with the blue Genie-lift. The sagging was reduced to ~3".

The Genie-lift platform was raised to support the sagging crane jib-trolley. The lab was closed off to ensure safety and experts were called in for consultation. It was decided to bring in professional riggers.

Halbert Brothers, Inc. rigging contractor came to the lab Tuesday morning to fix the crane. The job was to unload the I-beam with safety support below. They did a very good job.

The static deformation of I-beams sprung back to normal position. There are some deformation of the I-beam ~2 mm where the beams were jammed under load.

It is not clear if this is a new deformation or if the crane sections have always been mis-aligned by a couple of mm.

The crane was tested with 450 lbs load at 12 ft horizontal travel position. The folding of I-beams were repeatedly tested for safe operation. Its a 1 ton crane, but we tested it with 450 lbs because that's what we had on hand.

We're working on the safety upgrade of this lift to prevent similar accident from happening.

Pictures below:

Atm 1)   load testing 2007

Atm 2)   jammed-sagging under ~400 lbs, horizontal          

Atm.3)   jammed-folded 50 degrees, vertical     

Atm.4)   static deformation of I-beams

Atm.5)   unloading in progress with the help of two A-frames          

Atm.6)   it is unloaded

Atm.7-8) load testing        

Atm.9)   latch locked down for safe operation            

Atm.9)   zoom in of the crane sections misalignment    

[Jenne, Kyung Ha]

We made some good progress on suspending the Tip Tilt ECDs today.  We finished one whole set, plus another half.  The half is because one of the screw holes on the lower right ECD somehow got cross threaded.  The ECD and screws in question were separately wrapped in foil to mark them as iffy.  We'll redo that second half tomorrow.  This makes a total of 2.5 (including yesterday's work) ECD backplanes suspended.  The only thing left for these ones is to trim up the excess wire.

We also (with Koji) took a look at the jig used for suspending the mirror holder.  It looks like it was designed for so many Tip Tilt generations ago as to be basically useless for the 40m TTs.  The only really useful thing we'll get out of it is the distance between the suspension block and the mirror holder clamps.  Other than that we'll have to make do by holding the mirror and block at the correct distance apart, utilizing a ruler, calipers, or similar.  Rana pointed out that we should slightly bend the blade springs up a bit, so that when they are holding the load of the mirror holder, they sit flat. 

Attached below are 2 different pictures of one of the ECD backplane sets that has been suspended.  One with black background to illustrate the general structure, and one with foil background to emphasize the wires.

[Rana, Jenne]

We discovered to our great dismay that several important channels (namely C1:IOO-MC_L, but also everything on c1susvme2) are not being recorded, and haven't been since May 17th.  This corresponds to the same day that some other upgrade computers were installed.  Coincidence?

We've rebooted pretty much every FE computer and the FrameBuilder and DAQ_CONTROL approximately 18 times each (plus or minus some number).  No matter what we do, or what channels we comment out of the C1SUS2.ini file, we get a Status on the DAQ_Detail screen for c1susvme2 of 0x1000.  Except sometimes it is 0x2000.  Anyhow, it's bad, and we can't make it good again. 

I have emailed Joe about fixing this (with some assistance from Alberto, since we all know how much he likes doing the Nuclear Reboot option for the computers :)

Nancy and Koji:

This is what I and Koji measured after aligning the MC in the afternoon.

MC_Trans 4.595 (avg)

MC_Refl 0.203 (avg)

MC2_trans :

power = 1.34mW

13.5% width : x=6747.8 +- 20.7 um  , y = 6699.4+- 20.7 um

Hmm. I expect that you will put more details of the work tomorrow.
i.e. motivation, method, result (the previous entry is only this),
and some discussiona with how to do next.

This has been fixed, thanks to some help from Alex. It doesn't correspond to new computers being put in, but rather corresponds to a dcu_id change I had made in the new LSC model.

The fundamental problem is way back when I built the new LSC model using "lsc" as the name instead of something like "tst", I forgot to go to the current frame builder master file (/cvs/cds/caltech/chans/daq/master) and comment out the C1LSC.ini line. Initially there was no conflict with c1susvme, because the initially was dcu_id 13. The dcu_id was eventually changed to 10 from 13 , and thats when it conflicted with the c1susvme2 dcu_id which was also 10. I checked it against wiki edits to my dcu_id list page and I apparently updated the list on May 20th when it changed from 13 to 10, so the time frame fits.  Apparently it was previously conflicting with C0GDS.ini or C1EXC.ini, which both seem to have dcu_id = 13 set, although the C1EXC file is all commented out. The C0GDS.ini file seems to be LSC and ASC test points only.

The solution was to comment out the C1LSC.ini file line in the /cvs/cds/caltech/chans/daq/master file and restart the framebuilder with the fixed file.

After talking with Rolf, and clarifying exactly which machine I wanted, he gave me an 4600 Sun machine (similar to our current megatron).  I'm currently trying to find a good final place for it, but its at least here at the 40m. 

I also acquired 3 boards to plug our current VMIPMC 5565 RFM cards into, so they can be installed in the IO chassis.  These require +/- 5V power be connected to the top of the RFM board, which would be not possible in the 1U computers, so they have to go in the chassis.  These style boards prevent the top of the chassis from being put on (not that Rolf or Jay have given me tops for the chassis).  I'm planning on using the RFM cards from the East End FE, the LSC FE, and the ASC FE. 

I talked to Jay, and offered to upgrade the old megatron IO chassis myself if that would speed things up.  They have most of the parts, the only question being if Rolf has an extra timing board to put in it.  Todd is putting together a set of instructions on how to put the IO chassis together and he said he'd give me a copy tomorrow or Monday.  I'm currently planning on assembling it on Monday.  At that point I only need 1 more IO chassis from Rolf.

NEW CDS SETUP CHANGE:

When I asked about the dolphin IO chassis, he said we're not planning on using dolphin connections between the chassis and computer anymore.  Apparently there was some long distance telecon with the dolphin people and they said the Dolphin IO chassis connection and RFM doesn't  well together (or something like that - it wasn't very clear from Rolf's description).  Anyways, the other style apparently is now made in a fiber connected version (they weren't a year ago apparently), so he's ordered one.  When I asked why only 1 and what about the IOO computer and chassis, he said that would either require moving the computer/chassis closer or getting another fiber connection (not cheap).

So the current thought I hashed out with Rolf briefly was:

We use one of the thin 1U computers and place that in the 1Y2 rack, to become the IOO machine.  This lets us avoid needing a fiber.  Megatron becomes the LSC/OAF machine, either staying in 1Y3 or possibly moving to 1Y4 depending on the maximum length of dolphin connection because LSC and the SUS machine are still supposed to be connected via the Dolphin switch, to test that topology.

I'm currently working on an update to my CDS diagram with these changes and will attach it to this post later today.

 Just as I expected, since these hunuman didn't actually check MC_L after doing this stuff, MC_L was only recording ZERO. Joe and I reset and restarted c1susmve2 and then

verified (for real this time) that the channel was visible in both the Dataviewer real time display as well as in the trend.

The lesson here is that you NEVER trust that the problem has been fixed until you check for yourself. Also, we must always

specify a very precise test that must be used when we ask for help debugging some complicated software problem.

Single layer of stack successfully modeled in COMSOL. I'm working on trying to add Viton springs now and extend it to a full stack. Having some difficulty with finding consistent parameters to work with.

Last night, we successfully connected and powered our circuit, which allowed us to test whether our OSEMs were working.  Previously, we had been unable to accomplish this because (1) we weren't driving it sufficiently high voltage, and  (2) we didn't check that the colored leads on our circuit actually corresponded to the colored ports on the power supply (they were all switched, which we are in the process of rectifying), so our circuit was improperly connected to the supply .  Unfortunately, we didn't learn this until after nearly cooking our circuit, but luckily there appears to have been no permanent damage .

Our circuit specs suggested powering it with a voltage difference of 48V, so we needed to run our circuit at a difference of at least 36-40 V.  Since our power supply only supplied a difference of up to 30V in each terminal, we combined them in order to produce a voltage of up to double that.  We decided to power our circuit with a voltage difference of 40V (+/- 20V referenced to true ground).  The current at the terminals were 0.06 and 0.13 A. 

To test our circuit, we used a multimeter to check the supplied voltage at different test points, to confirm that an appropriate input bias was given to various circuit elements.  We identified the direction of LED bias on our OSEM, and connected it to our circuit. We were extremely gratified when we looked through the IR viewer and saw that, in fact, the LED in the OSEM was glowing happily .

We hooked up two oscilloscopes and measured the current through the coil, and also through the LED and photodiode in the OSEM.  We observed a change in the photodiode signal when we blocked the LED light, which was expected.  The signal at the PD and the LED were both sinusoidal waves around ~3 kHz.

We then went back to our levitation setup, and crudely tried to levitate a magnet with attached flag by using our hands and adjusting the gain (though we also could have been watching the PD current).  The first flag we tried was a soldering tip; we couldn't levitate this but achieved an interesting sort of baby-step "levitation" (levitation .15) which allowed us to balance the conical flag on its tip on top of the OSEM (stable to small disturbances).  After learning that conical flags are a poor idea, we switched our flag to a smaller-radius cylindrical magnet.  We were much closer to levitating this magnet, but were unable to conclusively levitate it .

 
Current plan:

Adjust the preset resistors to stabilize feedback

Check LED drive circuit.

Finish calculating the transfer function, and hook up the circuit to the spectrum analyzer to measure it as well.

Observe the signal from the photocurrent as disturbances block the LED light.

Play with the gain of the feedback to see how it affects levitation.

 

The WFS error signals were recorded in the order

WFS1_PIT

WFS1_YAW

WFS2_PIT

WFS2_YAW

these measurements are made in the linear region, that is the MC is nearly perfectly aligned.

This is  the average and std. dev.of 5 measurements taken of the same signals over 10 secs each. The std. dev are under 10%. And hence, I will be using 10 secs for measurements for the WFS signals after perturbations to the mirrors.

avg =

829.4408
-517.1884
297.4168
-944.7892


std_dev =

9.0506
22.9317
15.4580
8.9827

I perturbed the Pitch and Yaw of the Three mirrors (in order MC1,2,3), using ezcastep and calculated the coefficients that relate these perturbations to the WFS error signals.

The perturbation made is of -0.01 in each dof , and after measuring the WFS error for it, the system is reverted back to the previous point before making the other perturbation.

I was able to calculate the coefficients since I have assumed a linear relationship..

Following are the coefficients calculated using 10 secs measurements

coef_mat =

   1.0e+05 *

                            MC1_P   MC1_Y  MC2_P   MC2_Y    MC3_P   MC3_Y  constant
WFS1_PIT        -0.1262    0.3677   -0.4539   -0.6297   -0.1889   -0.1356   0.013664
WFS1_YAW     -0.0112   -0.7415   -0.1844    2.4509   -0.0023   -0.3531  -0.016199
WFS2_PIT         0.1251    0.4824   -0.2028   -0.6188    0.0099   -0.1490   0.006890
WFS2_YAW      0.0120   -0.7957   -0.1793    0.9962   -0.0493    0.2672 -0.013695

Also, I measured the same thing for 100s, and to my surprize, even the signs of coeficients are different.

coef_mat =

   1.0e+05 *

                           MC1_P   MC1_Y  MC2_P   MC2_Y    MC3_P   MC3_Y   constant
WFS1_PIT       -0.1981    0.3065   -0.6084   -0.9349   -0.4002   -0.3538   0.009796
WFS1_YAW     0.0607   -0.6977    0.0592    2.8753    0.3507    0.0373   -0.008194
WFS2_PIT        0.0690    0.4769   -0.2859   -0.7821   -0.1115   -0.2953  0.004150
WFS2_YAW     0.0580   -0.8153   -0.0937    1.1424    0.0650    0.4203  -0.010629

The reason I can understand is that the measurements were not made at the same time, and hence conditions might have changed.

A thing to note in all these coefficients is that they relate the error signals to the 'perturbation' around a certain point (given below). That point is assumed to lie in the linear region.

MC1_PIT      2.6129
MC1_YAW   -5.1781
MC2_PIT       3.6383
MC2_YAW    -1.2872
MC3_PIT      -1.9393
MC3_YAW    -7.518

I and Koji were trying to lock the mode cleaner for measuring the beam power at MC2 end. That is when we obtained the trans and refl values.

The beam characteristics at the MC2 were measured so that we could now use a dummy beam of similar power to test and characterize the QPD we are about to install at the MC2 end. This QPD wil provide two more signals in pitch and yaw, and hence complete 6 signals for 6 rotatioanl dof of the cavity. (4 are coming from WFS).

Once the QPD is characterised, it can be used to see the spot position at MC2. This is related to the mirror angles.

The width measurements were done using a beam scan. the beam scan was properly adjusted so that the maxima of the intensity of the sopt was at its center.

We also fitted gaussian curve to the beam profile, and it was a substantially good fit.

The whole idea is that I am trying  to look how the Wavefront sensors respond to the perturbations in the mirror angles. Once this is known, we should be able to control the mirror-movements.

the starting point would be to do just the DC measurements (which I did today). For proper analysis, AC measurements are obviously required.(will be done later).

The matrices so calculated can be inverted, and if found enough singular, the method can be used to control.

The first shot is to see teh dependency of teh error signals only on MC1 and MC3, and see if that is kind of enough to control these two mirrors.

If this works, the QPD signals could be used to control MC2 movements.

I just found the singular values and the condition number of the 4*4 matrix relating the WFS error signals and the MC1 and MC2 movements.

the condition number is ~12.5. I think its small enough to continue with the scheme. (if the measurements and all are reliable).

I turned off fb40m2 and fb40m temporarily while we added an extra power strip  to the (new) 1X6 rack at the bottom in the back.  This is to allow for the addition of the 4600 computer  given to us by Rolf (which needs a good name) into the rack above the fb machine.  The fb40m2 was unfortunately plugged into the main power connectors, so we unplugged two of its cables, and put them into the new strip. While trying to undo some of the rats nest of cables in the back I also powered down and unpluged briefly the c0dcu1, the pem crate, and the myrinet bypass box.

I am in the process of bringing those machines back up and restoring the network.

Also this morning, Megatron was moved from the end station into the (new) 1X3 rack, along with its router.  This is to allow for the installation of the new end computer and IO chassis.

Here are some more details about the current phasecam setup. We are using a He-Ne laser setup

A crude snap shot of the setup....

We sent light through SM2 (Steering Mirror 2)  to BS1(Beam-Splitter 1) where the laser light is split into two parts, one going to the AOM and the other to the EOM. The EOM adds 40 MHz sidebands to the incoming carrier light after SM3, and the AOM shifts the frequency of the incident light on it to 40.000 005 MHz. The purpose for doing this juggling is to intentionally create a beat signal off the reference beam from the AOM with the sidebands added at the EOM. Note that, we are driving the AOM at 7dBm and the EOM at 13 dBm with 0 (nil) modulation. The two lights are combined at the BS2 and sent off through SM5 to the camera. The CMOS of the camera contains silicon based Micro MT9V022 chip which has a quantum efficiency of 50% at 633 nm. Thus we expected a fairly good response to this He-Ne setup from the camera. 

Using a trigger circuit, we triggered the camera at 20 Hz by sending a 20Hz sinusoidal signal to it. The trigger circuit converts this to a positive square waves. Then I roughly figured out the optimum exposure time for the camera before the DC levels saturates it by writing a code for taking a series of 25 images at different exposure time. I found that 500µs seems to be a reasonable exposure time. So, using this data, I took 20 consecutive images and sent them through a short Fourier Transform segment using Matlab to see the beat signal. Note that the DC component from these processing of the images have some fringe pattern which is due to the ND 2.5 filter that we were using to reduce the light power incident on the camera. The FT method also gave us the presence of the beat signal at the corresponding bin of the FT (for example: for 5Hz beat signal, I got the DC at bin 1 of the FT and 5Hz component at bin 6 as expected). Then I changed the AOM driving frequency to 40.000 001 MHz in order to see a 1 Hz beat signal. The results for both is in my previous post. 

In order to increase the green power on the PSL table, I moved the position of the Second Harmonic Generation (SHG) crystal by ~5cm.

After this modification, the green power increased from 200 uW to 640 uW. This is sufficiently good.

     As I said in the past elog entry (# 3122), the power of the green beam generated at the PSL table should be about 650 uW.

I measured the green power by the Ophir power meter and found it was ~200 uW, which made me a little bit sad.

Then I performed the beam scan measurement to confirm if the crystal  was  located on the right place. And I found the postion was off from the optimum position by ~5cm.

So I slided the postion of the SHG oven to the right place and eventually the power got increased to 640 uW.

some notes: 

(power measurement)

        The outgoing beam from the SHG crystal is filtered by Y1-45S to eliminate 1064nm.

According to Mott's measurement Y1 mirrors are almost transparent for green beams (T~90%), but highly reflective for 1064nm (T~0.5%).

All the green power were measured after the Y1 mirror by the Ophir configured to 532nm, though, the measured power might be offseted by a leakage of 1064nm from the Y1 mirror.

I didn't take this effect into account.

(beam scanning and positioning of crystal)

          Here is the properties of the incident beam. These numbers are derived from the beam scan measurement.

w0h             = 52.6657      +/- 0.3445 um

w0v             = 52.4798      +/- 0.1289  um

z0h             = 0.574683         +/- 0.001937 m

z0v             = 0.574325         +/- 0.0007267 m

Where the suffixes "h" and "v" stand for "horizontal" and "vertical" respectively.

The distances are calibrated such that it starts from the lens postion.

Both waist size are already sufficiently good because the optimum conversion can be achieved when the waist size is about 50um ( see this entry)

The measured data and their fitting results are shown in attachement 1.

         According to my past calculation the center of the crystal should be apart from the beam waist by 6.8mm (see this entry). 

So at first I put the oven exactly on the waist postion, and then I slided it by 6.8mm.

(to be done)

        I need to find an optimum temperature for the crystal in order to maximize the green power.

Previously the optimum temperature for the crystal was 38.4 deg. But after moving the position I found the optimum temperature is shifted down to around 37deg.

The AC filters will be checked and/or replaced today. This means the AC will be off for sort periods of time. Temperature and particle count will be effected some what.

See 800 days plot

The feedback signal going to the laser PZT at the X end station was measured in the daytime and the nighttime.

It's been measured while the laser frequency was locked to the arm cavity with the green light.

The red curve was measured at 3pm of 8/July Friday. And the blue curve was measured at 12am of 9/July Saturday. 

As we can see on the plot, the peak-peak values are followers

              daytime:  ~ 4Vpp

       nighttime:  ~1.8Vpp

It is obvious that the arm cavity is louder in the daytime by a factor of about 2.

Note: the feedback signal is sent to the PZT only above 1Hz because the low frequency part is stabilized mostly by the crystal temperature (see this entry)

I and koji setup the measurement of the QPD response to the pitch and yaw displacements of the beam spot.

We did this using a 100mW 1064nm laser. Its power was attenuated to ~ 1.9mW, and the spot size at the QPD position was 6000-7000 um .

The QPD was put on a translation stage, using which, the center of teh QPD wrt the beam spot could be moved in pitch and yaw.

Following are the measurements :

For yaw

:

The slope of teh linear region is -8356 /inch

 For pitch

The slope of the linear region in this is 9085/inch