40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  40m Log, Page 105 of 339  Not logged in ELOG logo
ID Date Author Typeup Category Subject
  2632   Tue Feb 23 14:56:24 2010 steveUpdateGeneralETMX optical table mass

Our janitor dropped one 48" long  fluorescent tube on the top cover of ETMX-isct. This accident made glasses fly all over the place.

He cleaned up nicely, but please beware of small glass pieces around ETMX chamber.

We did not clean up on the table in order to reserve oplev and green ITMX pointing alignment.

Plot below shows that the alignment was not effected.

 

 

Attachment 1: etmxmass.jpg
etmxmass.jpg
  2637   Wed Feb 24 12:08:31 2010 KojiUpdateComputersRFM goes red -> recovered by the nuclear option

Most of the RFM went red this morning. I took the nuclear option and it seemed to be recovered.

  2638   Wed Feb 24 16:11:15 2010 JenneUpdatePEMSeismic witnesses near MC1 tank moved

Since we're going to open the MC1 tank tomorrow, I've moved the MC1 accelerometers and the Guralp over to underneath MC2 for the vent.  I'll reconnect them later.

  2639   Thu Feb 25 11:21:06 2010 KojiUpdateGeneralTanks opened

[Steve, Bob, Joe, Zach, Alberto, Kiwamu, Koji]

We opened the OMC-IMC access connector, ITMX North door, and ITMY West door.
We worked from 9:30-11:00.
The work was quite smooth thanks to the nice preparation of Steve as usual.

Thank the team for the great work!

 

  2642   Fri Feb 26 01:00:07 2010 JenneUpdateCOCSuspension Progress

This is going to be a laundry list of the mile markers achieved so far:

* Guiderod and wire standoff glued to each ITMX and ITMY

* Magnets glued to dumbbells (4 sets done now).  ITMX has 244 +- 3 Gauss, ITMY has 255 +- 3 Gauss.  The 2 sets for SRM and PRM are 255 +- 3 G and 264 +- 3 G.  I don't know which set will go with which optic yet.

* Magnets glued to ITMX.  There were some complications removing the optic from the magnet gluing fixture.  The way the optic is left with the glue to dry overnight is with "pickle picker" type grippers holding the magnets to the optic.  After the epoxy had cured, Kiwamu and I took the grippers off, in preparation to remove the optic from the fixture.  The side magnet (thankfully the side where we won't have an OSEM) and dumbbell assembly snapped off.  Also, on the UL magnet, the magnet came off of the dumbbell (the dumbbell was still glued to the glass).  We left the optic in the fixture (to maintain the original alignment), and used one of the grippers to glue the magnet back to the UL dumbbell.  The gripper in the fixture has very little slop in where it places the magnet/dumbbell, so the magnet was reglued with very good axial alignment.  Since after the side magnet+dumbbell came off the glass, the 2 broke apart, we did not glue them back on to the optic.  They were reattached, so that we can in the future put the extra side magnet on, but I don't think that will be necessary, since we already know which side the OSEM will be on.

* Magnets glued to ITMY.  This happened today, so it's drying overnight.  Hopefully the grippers won't be sticky and jerky like last time when we were removing them from the fixture, so hopefully we won't lose any magnets when I take the optic out of the fixture.

* ITMX has been placed in its suspension cage.  The first step, before getting out the wire, is to set the optic on the bottom EQ stops, and get the correct height and get the optic leveled, to make things easier once the wire is in place.  Koji and I did this step, and then we clamped all of the EQ stops in place to leave it for the night.

* The HeNe laser has been leveled, to a beam height of 5.5inches, in preparation for the final leveling of the optics, beginning tomorrow.  The QPD with the XY decoder is also in place at the 5.5 inch height for the op lev readout.  The game plan is to leave this set up for the entire time that we're hanging optics.  This is kind of a pain to set up, but now that it's there, it can stay out of the way huddled on the side of the flow bench table, ready for whenever we get the ETMs in, and the recoated PRM. 

* Koji and Steve got the ITMX OSEMs from in the vacuum, and they're ready for the hanging and balancing of the optic tomorrow.  Also, they got out the satellite box, and ran the crazy-long cable to control the OSEMs while they're on the flow bench in the clean room.

 

Koji and I discovered a problem with the small EQ stops, which will be used in all of the SOS suspensions for the bottom EQ stops.  They're too big.  :(  The original document (D970312-A-D) describing the size for these screws was drawn in 1997, and it calls for 4-40 screws.  The updated drawing, from 2000 (D970312-B-D) calls for 6-32 screws.  I naively trusted that updated meant updated, and ordered and prepared 6-32 screws for the bottom EQ stops for all of the SOSes.  Unfortunately, the suspension towers that we have are tapped for 4-40.  Thumbs down to that.  We have a bunch of vented 4-40 screws in the clean room cabinets, which I can drill, and have Bob rebake, so that Zach and Mott can make viton inserts for them, but that will be a future enhancement.  For tonight, Koji and I put in bare vented 4-40 screws from the clean room supply of pre-baked screws.  This is consistent with the optics in our chambers having bare screws for the bottom EQ stops, although it might be nicer to have cushy viton for emergencies when the wire might snap.  The real moral of this story is: don't trust the drawings.  They're good for guidelines, but I should have confirmed that everything fit and was the correct size.

  2643   Fri Feb 26 11:48:36 2010 KojiUpdateGeneralMC incident beam shift

Last night I worked on the MC incident beam such that we can hit the center of the MC mirrors.

Steve and I checked the incident beam on MC1. We found the beam is ~5mm south.
This was not too critical but it is better to be realigned. I moved the steering mirror on the OMC
table (in vac). We kept the MC resonated. After the maximization of the resonance, I realigned the
MC1 and MC3 such that the resonance in dominated by TEM00.

Jenne, Kiwamu, and I then closed the light door on to the OMC/IMC.

I will make more detailed entry with photos in order to explain what and how I did.

  2646   Sun Feb 28 23:47:52 2010 ranaUpdateComputersrosalba

Since Rosalba wanted to update ~500 packages, I let it do it. This, of course, stopped the X server from running. I downloaded and installed the newest Nvidia driver and its mostly OK.

The main problem with the auto-update on our workstations is that we've updated some packages by hand; i.e. not using the standard CentOS yum. So that means that the auto-update doesn't work right. From now on, if you want to install a fancier package than what CentOS distributes, you should commit to handle the system maintenance for these workstations for the future. Its not that we can't have new programs, we just have to pay the price.

 

At 23:45 PST, I also started a slow triangle wave on the AOM drive amplitude. This is to see if there's a response in the FSS-FAST which might imply a coupling from intensity noise to frequency noise via absorbed power and the dn/dT effect in the coatings.

Its a 93 second period triangle modulating the RC power from 100% down to 50%.

  2649   Mon Mar 1 22:38:12 2010 ranaUpdateComputersRC sensitivity to RIN

The overnight triangle wave I ran on the AOM drive turns out to have produced no signal in the FAST feedback to the PZT.

The input power to the cavity was ~10 mW (I'm totally guessing). The peak-peak amplitude of the triangle wave was 50% of the total power.

The spectral density of the fast signal at the fundamental frequency (~7.9 mHz) is ~0.08 V/rHz. The FAST calibration is ~5 MHz/V. So, since we

see no signal, we can place an upper limit on the amount of frequency shift = (5 MHz/V) * (0.08 V/rHz) * sqrt(0.0001 Hz) = 4 kHz.

Roughly this means that the RIN -> Hz coefficient must be less than 4 kHz / 5 mW or ~ 1 Hz/uW.

For comparison, the paper on reference cavities by the Hansch group lists a coefficient of ~50 Hz/uW. However, they have a finesse of 400000

while we only have a finesse of 8000-10000. So our null result means that our RC mirrors' absorption is perhaps less than theirs. Another possibility

is that their coating design has a higher thermo-optic coefficient. This is possible, since they probably have much lower transmission mirrors. It would be

interesting to know how the DC thermo-optic coefficient scales with transmission for the standard HR coating designs.

Attachment 1: Untitled.png
Untitled.png
  2650   Tue Mar 2 12:20:54 2010 kiwamuUpdatePSLstray beam

In order to block stray beams, I have put some beam dumps and razor blades on the PSL  table.

There were three undesired spots in total. I found two spots on the south side door of the PSL room, close to Mach-Zehnder.

Another spots was on the middle of the north door. Now they all are blocked successfully.

  2651   Tue Mar 2 23:11:43 2010 KojiUpdateSUSITMX hung

Jenne and Koji

We successfully hung ITMX on the SOS. Side magnet is ~2mm off from the center of the OSEM. ITMX aligned using the QPD. The OSEMs changes the alignment. It looks that something magnetic is inside the OSEM PD or LED.

Reguled ITMY side magnet.

Cleaned up the lab for the safety inspection.

  2652   Wed Mar 3 02:57:29 2010 JenneUpdateSUSITMX hung

Quote:

Jenne and Koji

We successfully hung ITMX on the SOS. Side magnet is ~2mm off from the center of the OSEM.

Reguled ITMY side magnet.

Cleaned up the lab for the safety inspection.

 Some details on the side magnet situation from today: 

To glue the magnets+dumbbells to the optics, we use the magnet-dumbbell gluing fixture.  This fixture is supposed to have teflon 'pads' for the optic to sit on while you align it in the fixture, however the fixture which we received from MIT (it's Betsy's....but it came via MIT) only had one of the 4 teflon pads. 

Kiwamu and I decided (last week, when we first glued ITMX's magnets) that it would be bad news to let the AR face of the optic sit on bare metal, so we fashioned up some teflon pads using stock in a cabinet down the Yarm.  We were focused on thinking about the face magnets, and didn't think about how the thickness of the teflon affected the placement of the side magnet.  We chose some teflon that was too thin by ~1mm, so the optic sat too low in the fixture, resulting in the side magnet being glued too close to the HR side of the optic (this is all along the Z - axis, where Z is the direction of beam propagation). 

Why it ended up being 2mm off instead of only 1mm I don't really have an explanation for, other than perhaps tightening the set screws to hold the optic (by the barrel) in the fixture pushes the optic up.  I observed this happening when I didn't put any effort into keeping the optic flat on the teflon pads, but I thought that I made sure the optic was seated nicely in the fixture before starting to glue.  When I glued the new ITMY side magnet tonight I tried to make sure that the optic was seated nicely in the fixture.  We'll see what happens.

Before gluing the new ITMY side magnet (and now it's set for all future magnet gluings....), I found 4 teflon pads of all the correct thickness.  It turns out that we have a magnet gluing fixture of our own, which I found in the cabinets in the clean room.  This fixture had all 4 teflon pads, so I stole them and put them into the one that we're using for this round of upgrade / suspension hangings.  The height of all future side magnets should be correct. The thickness of the pads in the 'spare' fixture matched the one which came with the fixture from MIT as closely as I could feel by putting them on the same flat surface next to each other and feeling if there was a step. 

A side note about this magnet gluing fixture that I found:  It has the word "TOP" etched into it, to prevent exactly my problem with the ITMY side magnets in the first place.  Unfortunately the threads for the set screws which hold the optic are shot (or something is funny with them), so we can't just use this fixture. 

Gluing notes regarding the standoffs and guiderods:

There's more glue than I'd like on the guiderods / standoff for ITMX.  The glue was starting to get a little tacky when I glued the standoff in place after we balanced the optic, so it was hard to get it in the right place.  I'm confident we have a good epoxy contact, and we don't have much glue that I think it'll be a big problem.  Certainly I'll be a lot better at manuvering my glue-stick a.k.a skinny piece of wire around the suspension tower to get to the standoff for the rest of the optics that we're hanging, and I won't have glued something like ITMY side magnet immediately beforehand, which took enough time that the glue started to get tacky (not very tacky, just barely noticeably tacky).

I'd say that most gluing activities should be completed within ~10-15min of mixing the glue, after spending ~2min stirring to make sure it's nice and uniform.  It doesn't dry fast enough to be a huge rush, but you should get right on the gluing once the epoxy has been mixed. 

  2653   Wed Mar 3 18:32:25 2010 AlbertoUpdate40m Upgrading11 MHz RFPD elctronics
** Please add LISO file w/ component values.
 
I designed the circuit for one of the 11 MHz photodiodes that we're going to install in the 40m Upgrade.

This is a simple representation of the schematic:

          gnd
#          |
#          Cw2
#          |
#          n23
#          |
#          Lw2
#          |
#           n22
#          |
#          Rw2                
#                 |                   |\            
#           n2- - - C2 - n3 -  - -  - |  \          
#            |    |      |   |        |4106>-- n5 - Rs -- no
# iinput    Rd   L1     L2 R24    n6- |  /     |           |
#      nin - |    |      |   |    |   |/       |         Rload    
#           Cd   n7     R22 gnd   |            |           |          
#            |    |      |        | - - - R8 - -          gnd              
#           gnd  R1     gnd      R7 
#                 |               |
#         gnd               gnd
#                 
#
#

I chose the values of the components in a realistic way, that is using part available from Coilcraft or Digikey.

Using LISO I simulated the Tranfer Function and the noise of the circuit.

I'm attaching the results.

I'll post the 55MHz rfpd later.

Attachment 1: rfpd11_v2_TF.pdf
rfpd11_v2_TF.pdf
Attachment 2: rfpd11_v2_Noise.pdf
rfpd11_v2_Noise.pdf
  2654   Thu Mar 4 02:25:14 2010 JenneUpdateCOCFurther details on the magnet story, and SRM guiderod glued

[Koji, Jenne]

First, the easy story:  SRM got it's guiderod & standoff glued on this evening.  It will be ready for magnets (assuming everything is sorted out....see below) as early as tomorrow.  We can also begin to glue PRM guiderods as early as tomorrow.

The magnet story is not as short.....

Problem: ITMX and ITMY's side magnets are not glued in the correct places along the z-axis of the optic (z-axis as in beam propagation direction). 

ITMX (as reported the other day) has the side magnet placement off by ~2mm.  ITMX side was glued using the magnet fixture from MIT and the teflon pads that Kiwamu and I improvised.

It was determined that the improvised teflon pads were too thin (maybe about 1m thick), so I took those out, and replaced them with the teflon pads stolen from the 40m's magnet gluing fixture.   (The teflon pad from the MIT fixture and the ones from the MIT fixture are the same within my measuring ability using a flat surface and feeling for a step between them.  I haven't yet measured with calipers the MIT pad thickness).  The pads from the 40m fixture, which were used in the MIT fixture to glue ITMY side last night were measured to be ~1.7mm thick.

Today when Koji hung ITMY, he discovered that the side magnet is off by ~1mm.  This improvement is consistent with the switching of the teflon pads to the ones from the 40m fixture.

We compared the 40m fixture with the one from MIT, and it looks like the distance from the edge of where the optic should sit to the center of the hole for the side magnet is different by ~1.1mm.  This explains the remaining ~1mm that ITMY is off by. 

We should put the teflon pads back into the 40m fixture, and only use that one from now on, unless we find an easy way to make thicker teflon pads for the fixture we received from MIT.  (The pads that are in there are about the maximum thickness that will fit).  I'm going to use my thickness measurements of SRM (taken in the process of gluing the guiderods) to see what thickness of pads / what fixture we want to actually use, but I'm sure that the fixture we found in the 40m is correct.  We can't use this fixture however, until we get some clean 1/4-28 screws.  I've emailed Steve and Bob, so hopefully they'll have something for us by ~lunchtime tomorrow. 

The ITMX side magnet is so far off in the Z-direction that we'll have to remove it and reglue it in the correct position in order for the shadow sensor to do anything.  For ITMY, we'll check it out tomorrow, whether the magnet is in the LED beam at all or not.  If it's not blocking the LED beam enough, we'll have to remove and reglue it too. 

Why someone made 2 almost identical fixtures, with a 1mm height difference and different threads for the set screws, I don't know.  But I don't think whoever that person was can be my friend this week. 

  2655   Thu Mar 4 08:43:35 2010 AlbertoUpdate40m Upgrading11 MHz RFPD elctronics

Quote:
** Please add LISO file w/ component values.

oops, forgotten the third attachment...

here it is

Attachment 1: rfpd11_v2.fil
# Resonant RF diode front end
#
#		  gnd
#		  |
#		  Cw2
#		  |
#		  n23
#		  |
#		  Lw2
#		  |
... 60 more lines ...
  2656   Thu Mar 4 19:53:56 2010 AlbertoUpdate40m Upgrading11MHz PD designed adjusted for diode's resistance; 55 MHz RFPD designed
After reading this study done at LIGO MIT in 1998 I understood why it is difficult to define an effective impedance for a photodiode.

I read a few datasheets of the C30642GH photodiode that we're going to use for the 11 and 55 MHz. Considering the  values listed for the resistance and the capacitance in what they define "typical conditions" (that is, specific values of bias voltage and DC photocurrent) I fixed Rd=25Ohms and Cd=175pF.

Then I picked the tunable components in the circuit so that we could adjust for the variability of those parameters.

Finally with LISO I simulated transfer functions and noise curves for both the 11 and the 55MHz photodiodes.

I'm attaching the results and the LISO source files.

 

Attachment 1: rfpd55_Noise.pdf
rfpd55_Noise.pdf
Attachment 2: rfpd55_TF.pdf
rfpd55_TF.pdf
Attachment 3: rfpd11_v2_TF.pdf
rfpd11_v2_TF.pdf
Attachment 4: rfpd11_v2_Noise.pdf
rfpd11_v2_Noise.pdf
Attachment 5: rfpd11_v2.fil
Attachment 6: rfpd55.fil
  2657   Thu Mar 4 22:07:21 2010 ranaUpdate40m Upgrading11MHz PD not yet designed

Use 10 Ohms for the resistance - I have never seen a diode with 25 Ohms.

p.s. PDFs can be joined together using the joinPDF command or a few command line options of 'gs'.

  2658   Fri Mar 5 11:21:18 2010 steveUpdateSUSused OSEMs are magnetic

Quote:

Jenne and Koji

We successfully hung ITMX on the SOS. Side magnet is ~2mm off from the center of the OSEM. ITMX aligned using the QPD. The OSEMs changes the alignment. It looks that something magnetic is inside the OSEM PD or LED.

Reguled ITMY side magnet.

Cleaned up the lab for the safety inspection.

 The brand new OSEM LED and PD can be picked up with a weak magnet. These ferrous metals of LEDs and PDs will be magnetized by sitting in the sus next to the

magnets for years. I hanged optics with new OSEMs and never saw this effect before.

 

 

We have to demagnetize them.

  2659   Fri Mar 5 18:04:56 2010 ranaUpdateSUSused OSEMs are magnetic

The OSEM LEDs and PDs from Honeywell have always had some ferromagnetic material in them. These are the same OSEMs we had since 2000.

You must be thinking of the really old 20th century plastic OSEMs.

  2660   Sun Mar 7 07:01:21 2010 ranaUpdateWienerFilteringGuralp Huddle Test software

We need to do a new huddle test of the Guralps for the Wiener filtering paper. The last test had miserable results.

I tried to use recent data to do this, but it looks like we forgot to turn the Guralp box back on after the power outage or that they're far off center.

So instead I got data from after the previous power outage recovery.

I tried to use our usual Wiener filter method to subtract Guralp1-Z from Guralp2-Z, but that didn't work so well. It was very sensitive to the pre-weighting.

Instead I used the new .m file that Dmass wrote for subtracting the phase noise from his doubling noise MZ. That worked very well. It does all of the subtraction in the frequency domain and so doesn't have to worry about making a stable or causal filter. As you can see, it beats our weighted Wiener filter at all frequencies.

huddlez.png

The attached plot shows the Guralp spectra (red & green), the residual using time-domain Wiener filtering (black) and the Dmass f-domain code (yellow).

As soon as Jenne brings in her beer cooler, we're ready to redo the Huddle Test.

 

  2661   Sun Mar 7 23:05:39 2010 ranaUpdatePEMSeismic witnesses near MC1 tank moved

Quote:

Since we're going to open the MC1 tank tomorrow, I've moved the MC1 accelerometers and the Guralp over to underneath MC2 for the vent.  I'll reconnect them later.

 I've put both Guralps next to the Ranger and connected them to the breakout box. The data is now good.

I found that the Ranger was not centered and so it was stuck (someone kicked it in the last 2 weeks apparently). I recentered the mass according to the procedure in the manual. Its now moving freely.

In order to do a better huddle test, I increased the gain of the Ranger's SR560 preamp to 100 from 10 and put it on the low noise setting. I also enabled a 2x lowpass at 3 kHz for no good reason.

I couldn't find what the actual value of the gain of the Guralp breakout box is, but I assume its 10. With this assumption the calibrations are this:

Guralp: 800 V/(m/s)  *  10  (V/V)   *  16384  cts/V   =>    7.63e-9  (m/s)/count           (0.03 - 40 Hz)

Ranger:  345 V/(m/s)  * 100 (V/V)  *  16384 cts/V   =>     1.77e-9  (m/s)/count          (above 1Hz)

To account for the fact that I am not damping the Ranger with an external damping resistor, I have changed the calibration poles and zeros: in DTT we now use 2 poles @ 0 Hz and a complex pair at 1 Hz:

G = 1.77e-9

Poles = 0, 0

Zeros = 0.15 0.9887

I think that the Guralp gain is too high by a factor of 2. To really do this right, we should attach a known voltage to the input pins of the Guralp breakout and then read off the amount of counts.

Attachment 1: seis.png
seis.png
  2662   Mon Mar 8 18:15:27 2010 ranaUpdatePEMStyrofoam Cooler on the Seismos

I put Jenne's cooler over the seismometers. Kiwamu put the copper foil wrapped lead brick on top of the cooler to hold it down. I also put another (unwrapped) lead brick on top of the Guralp cables outside of the cooler. Frank gave me a knife with which I cut a little escape hole in the bottom of the cooler lip for the Guralp cables to sneak out of.

Attachment 1: SeismometersHuddled.jpg
SeismometersHuddled.jpg
  2663   Tue Mar 9 09:04:20 2010 steveUpdatePEMkeep vacuum chamber closed

They are sandblasting at CES: our particle counts are very high. DO NOT OPEN CHAMBER!

Attachment 1: sandblasting.jpg
sandblasting.jpg
  2665   Tue Mar 9 12:06:53 2010 rana, JenneUpdatePEMStyrofoam Cooler on the Seismos

Looks like the GUR2_X signal is bad. Jenne says that we need to center it mechanically before the signals will become useful again. Maybe Steve will do this - instructions are in the manuel ?

  2666   Wed Mar 10 15:02:58 2010 ranaUpdatePEMStyrofoam Cooler on the Seismos

This is the spectra and coherence from a quiet time last night. I've lowered the Guralp cal by a factor of 2 to account for the fact that the gain in the breakout box is actually 20 and not 10 as I previously said.

The AD620 stage in the front part has a gain of 10 and then there's a single-to-differential stage in the output which gives us a gain of 2. The DTT cal in counts is now 3.8e-9 (m/s)/count.

The second plot shows the Guralp and Ranger signals at the ADC input (converted from counts to Volts for usefulness). The thick grey line is the expected noise of the Guralp breakout box

(mainly the AD620) propagated to the ADC (via multiplication by 2). It looks like the preamp board should not be a problem as long as we can reach the AD620 limit.

So the excess noise in the Guralp is not the fault of the preamp, but more likely the mounting and insulation of the seismometers.

Attachment 1: Seismic-Ref_100310.png
Seismic-Ref_100310.png
Attachment 2: Untitled.gif
Untitled.gif
  2668   Thu Mar 11 17:51:04 2010 KojiUpdateSUSRecent status of SOSs

Jenne, Koji

Recent status of SOSs:

We completed one of the suspension (ITMY).

ITMX: 6 Magnets, standoffs, and guide rod glued / balance to be confirmed / needs to be baked
ITMY: 6 Magnets, standoffs, and guide rod glued / balance confirmed / needs to be baked
SRM: 6 Magnets, one standoff, and guide rod glued,  / waiting for the release from the gluing fixture.
PRM: one standoff, and guide rod glued / waiting for the magnet gluing. 

We think we solved all the problems for hanging the suspensions.

--- Magnet gluing fixture ---

  • There is the two kinds of fixtures. Neither does work propery in the original form!
  • The height of the side magnets should be finely adjusted by changing the teflon sheets beneath the optics in the fixture.
  • Be aware of the polarity of the fixture in terms of the side magnets
  • Wrongly glued magnets (and others) can be removed by a razor blade with some amount of acetone.
  • The pickle picker frequently knocks the magnets down during the release. Don't s be down in the dumps too much.

--- Suspending the mirror ---

  • The wire winches must be carefully attached to the suspension tower such that the wires are not streached during fastening the clamps.
  • There are a couple variations of the drawings for SOS. The one we have has #4-40 for the earthquake stops at the bottom.
    Zach and Mott made the EQ stops with the right size.
  2669   Fri Mar 12 13:52:18 2010 ZachUpdateelogelog restarted

 The elog was down and I ran the restart script.

  2671   Sat Mar 13 21:30:22 2010 ranaUpdatePEMStyrofoam Cooler on the Seismos

Untitled.png

 

  2672   Sat Mar 13 22:16:03 2010 ranaUpdateWienerFilteringGuralp Huddle Test software

I used some recent better data to try for better Z subtraction.

Dmass helped me understand that sqrt(1-Coherence) is a good estimate of the theoretical best noise subtraction residual. This should be added to DTT. For reference the Jan statistic is the inverse of this.

This should get better once Steve centers the Guralps. 

Attachment 1: guralpznoise.png
guralpznoise.png
  2673   Mon Mar 15 09:43:47 2010 steveUpdatePEMmore sandblasting today

Do not open IFO vacuum envelope today! They are sandblasting again at CES

  2674   Mon Mar 15 16:39:36 2010 steveUpdatePEMGuralp2 centered

Quote:

Untitled.png

 

Guralp 2 centered.The mass position offsets are: E-W 0.05V, N-S 0V, Z 0.4V

Guralp 1: E-W -0.1V, N-S -0.25V, Z 0V measured, not adjusted

The GUR2_X channel has an offset. See plot below when seismometers are disconnected. This offset has to be removed.

NOTE: this huddle is on bad-soft ground-lenoleum tile from prehistoric Flintstone age

 

Attachment 1: grlp2ffst.jpg
grlp2ffst.jpg
  2675   Tue Mar 16 04:22:02 2010 JenneUpdateEnvironmentEarthquake, Mag 4.4

Earthquake Details

Magnitude 4.4
Date-Time
  • Tuesday, March 16, 2010 at 11:04:00 UTC
  • Tuesday, March 16, 2010 at 04:04:00 AM at epicenter
Location 33.998°N, 118.072°W
Depth 18 km (11.2 miles)
Region GREATER LOS ANGELES AREA, CALIFORNIA
Distances
  • 2 km (1 miles) ENE (58°) from Pico Rivera, CA
  • 4 km (3 miles) ESE (115°) from Montebello, CA
  • 4 km (3 miles) SSW (207°) from Whittier Narrows Rec. Area, CA
  • 9 km (5 miles) NE (39°) from Downey, CA
  • 9 km (6 miles) SSW (206°) from El Monte, CA
  • 17 km (11 miles) ESE (112°) from Los Angeles Civic Center, CA
Location Uncertainty horizontal +/- 0.4 km (0.2 miles); depth +/- 0.9 km (0.6 miles)
Parameters Nph=122, Dmin=5 km, Rmss=0.37 sec, Gp= 25°,
M-type=local magnitude (ML), Version=2
Source
Event ID

ci14601172

-----------------------------------------

MC1 and MC3 seem to have kept themselves together, but all the other optics' watchdogs tripped.

Attachment 1: EQ_16Mar2010.png
EQ_16Mar2010.png
  2676   Tue Mar 16 05:10:39 2010 kojiUpdateEnvironmentEarthquake, Mag 4.4

Some of the suspensions got watchdog tripped -> enabled -> damped.

The MC mirrors got slightly misaligned.

 

Attachment 1: 100316_MC_SUS.png
100316_MC_SUS.png
  2677   Tue Mar 16 09:37:30 2010 steveUpdateSUSeq 4.4 seen by oplevs and osems

The oplev plots clearly show the alignment effect of this eq.

Attachment 1: opleveq4.4.jpg
opleveq4.4.jpg
Attachment 2: eq4.4.jpg
eq4.4.jpg
Attachment 3: opleveq4.4d3.jpg
opleveq4.4d3.jpg
  2678   Thu Mar 18 08:49:51 2010 steveUpdatePEMGuralp2 centered again ?

 

Someone adjusted the Guralp2 mass position last night??

NO

Attachment 1: grlp2xadj.jpg
grlp2xadj.jpg
  2679   Thu Mar 18 10:46:51 2010 KojiUpdateABSLPLL reconstructed

Last night (Mar 17) I checked the PLL setup as Mott have had some difficulty to get a clean lock of the PLL setting.

  • I firstly found that the NPRO beam is not going through the Faraday isolator well. This was fixed by aligning the steering mirrors before the Faraday.
     
  • The signal from the RF PD was send to the RF spectrum analyzer through a power splitter. This is a waist of the signal. It was replaced to a directional coupler.
     
  • Tee-ing the PZT feedback to the oscilloscope was producing the noise in the laser frequency. I put the oscilloscope to the 600Ohm output of the SR560, while connectiong the PZT output to the 50Ohm output.
     
  • In addition, 6dB+6dB attenuators have been added to the PZT feedback signal.

Now the beating signal is much cleaner and behave straight forward. I will add some numbers such as the PD DC output, RF levels, SR560 settings...

Now I am feeling that we definitely need the development of really clean PLL system as we use PLL everywhere! (i.e. wideband PD, nice electronics, summing amplifiers, stop poking SR560, customize/specialize PDH box, ...etc)

  2680   Thu Mar 18 12:27:56 2010 AlbertoUpdateABSLPLL reconstructed

Quote:

Last night (Mar 17) I checked the PLL setup as Mott had some difficulty to get a clean lock of the PLL setting.

  • I firstly found that the NPRO beam is not going through the Faraday isolator well. This was fixed by aligning the steering mirrors before the Faraday.
     
  • The signal from the RF PD was send to the RF spectrum analyzer through a power splitter. This is a waist of the signal. It was replaced to a directional coupler.
  • Tee-ing the PZT feedback to the oscilloscope was producing the noise in the laser frequency. I put the oscilloscope to the 600Ohm output of the SR560, while connectiong the PZT output to the 50Ohm output.
  • In addition, 6dB+6dB attenuators have been added to the PZT feedback signal.

Now the beating signal is much cleaner and behave straight forward. I will add some numbers such as the PD DC output, RF levels, SR560 settings...

Now I am feeling that we definitely need the development of really clean PLL system as we use PLL everywhere! (i.e. wideband PD, nice electronics, summing amplifiers, stop poking SR560, customize/specialize PDH box, ...etc)

I also had noticed the progressive change of the aux NPRO alignment to the Farady.

I strongly agree about the need of a good and robust PLL.

By modifying the old PDH box (version 2008) eventually I was able to get a PLL robust enough for my purposes. At some point that wasn't good enough for me either.

I then decided to redisign it from scratch. I'm going to work on it. Also because of my other commitments, I'd need a few days/1 week for that. But I'd still like to take care of it. Is it more urgent than that?

  2681   Thu Mar 18 13:40:35 2010 KojiUpdateABSLPLL reconstructed

We use the current PLL just now, but the renewal of the components are not immediate as it will take some time. Even so we need steady steps towards the better PLL. I appreciate your taking care of it.

Quote:

Quote:

Last night (Mar 17) I checked the PLL setup as Mott had some difficulty to get a clean lock of the PLL setting.

  • I firstly found that the NPRO beam is not going through the Faraday isolator well. This was fixed by aligning the steering mirrors before the Faraday.
     
  • The signal from the RF PD was send to the RF spectrum analyzer through a power splitter. This is a waist of the signal. It was replaced to a directional coupler.
  • Tee-ing the PZT feedback to the oscilloscope was producing the noise in the laser frequency. I put the oscilloscope to the 600Ohm output of the SR560, while connectiong the PZT output to the 50Ohm output.
  • In addition, 6dB+6dB attenuators have been added to the PZT feedback signal.

Now the beating signal is much cleaner and behave straight forward. I will add some numbers such as the PD DC output, RF levels, SR560 settings...

Now I am feeling that we definitely need the development of really clean PLL system as we use PLL everywhere! (i.e. wideband PD, nice electronics, summing amplifiers, stop poking SR560, customize/specialize PDH box, ...etc)

I also had noticed the progressive change of the aux NPRO alignment to the Farady.

I strongly agree about the need of a good and robust PLL.

By modifying the old PDH box (version 2008) eventually I was able to get a PLL robust enough for my purposes. At some point that wasn't good enough for me either.

I then decided to redisign it from scratch. I'm going to work on it. Also because of my other commitments, I'd need a few days/1 week for that. But I'd still like to take care of it. Is it more urgent than that?

 

  2684   Thu Mar 18 21:42:26 2010 KojiUpdateABSLPLL reconstructed

I checked the setup further more.

  • I replaced the PD from NewFocus 1GHz one to Thorlabs PDA255.
  • I macthed the power level of the each beam.

Now I have significant fraction of beating (30%) and have huge amplitude (~9dBm).
The PLL can be much more stable now.

Koji

  2685   Fri Mar 19 18:00:14 2010 jenneUpdatePEMGuralp2 centered again

[Jenne, Sanjit]

It looks like Steve used a GND-12V supply to power the Guralp through the little breakout box (the box is for checking the centering of the mass).  This is BAD.  The Guralps want +/- 12V.

We centered all of the channels on Gur2, and checked the channels on Gur1, so we'll see how they're feeling after a while.

  2686   Fri Mar 19 21:15:33 2010 ranaUpdatePEMGuralp2 centered again

This trend of the last 200 days shows that GUR2 has been bad forever...until now anyways.

Attachment 1: Untitled.png
Untitled.png
  2687   Fri Mar 19 23:03:41 2010 ranaUpdatePEMGuralp2 centered again

I went and double-checked and aligned the styrofoam cooler at ~5:00 UTC. It was fine, but we really need a better huddling box. Where's that granite anyway?

Here's the new Huddle Test output. This time I show the X-axis since there's some coherence now below 0.1 Hz.

You'll also notice that the Wiener filter is now beating the FD subtraction. This happened when I increased the # of taps to 8000. Looks like the noise keeps getting lower as I increase the number of taps, but this is really a kind of cheat if you think about it carefully.

Attachment 1: huddlez.png
huddlez.png
  2689   Sun Mar 21 19:25:29 2010 ranaUpdatePEMGuralp2 centered again

From this morning, now in calibrated units, and with the Güralp self noise spec from the Güralp manual.

Attachment 1: huddlez.png
huddlez.png
  2690   Sun Mar 21 20:08:20 2010 kiwamu, ranaUpdatePSLEOM wasit size

We are going to set the waist size to 0.1 mm for the beam going through the triple resonant EOM on a new PSL setup.

When we were drawing a new PSL diagram, we just needed to know the waist size at the EOM in order to think about mode matching.

waist.png

This figure shows the relation between the waist size and the spot size at the aperture of the EOM.

The x-axis is the waist size, the y-axis is the spot size. It is clear that there is a big clearance at 0.1 mm waist size. This is good.

Also it is good because the waist size is much above the damage threshold of the EO crystal (assuming 1W input).

The attached file is the python code for making this plot.

Attachment 2: waist.py.zip
  2691   Sun Mar 21 21:02:39 2010 KojiUpdatePSLEOM waist size
You don't need a lengthy code for this. It is obvious that the spot size at the distance L is minimum when L =
zR, where zR is the Rayleigh range. That's all.

Then compare the spot size and the aperture size whether it is enough or not.

It is not your case, but if the damage is the matter, just escape to the large zR side. If that is not possible
because of the aperture size, your EOM is not adequate for your purpose.
  2694   Mon Mar 22 11:37:09 2010 steveUpdatePEMjackhammering

There was more jackhammering this morning just about 20 ft north-west of the beamsplitter chamber, outside.

Attachment 1: jackhammering2.jpg
jackhammering2.jpg
  2696   Mon Mar 22 22:11:26 2010 MottUpdateABSLPLL reconstructed

 

 It looks like the PLL drifted alot over the weekend, and we couldn't get it back to 9 dBm.  We switched back to the new focus wideband PD to make it easier to find the beat signal.  I replaced all the electronics with the newly fixed UPDH box (#17) and we aligned it to the biggest beat frequency we could get, which ended up being -27 dBm with a -6.3V DC signal from the PD.  

Locking was still elusive, so we calculated the loop gain and found the UGF is about 45 kHz, which is too high.  We added a 20 dB attenuator to the RF input to suppress the gain and we think we may have locked at 0 gain.  I am going to add another attenuator (~6 dB) so that we can tune the gain using the gain knob on the UPDH box.  

Finally, attached is a picture of the cable that served as the smb - BNC adaptor for the DC output of the PD.  The signal was dependent on the angle of the cable into the scope or multimeter.  It has been destroyed so that it can never harm another innocent experiment again!

Attachment 1: IMG_0150.JPG
IMG_0150.JPG
  2697   Mon Mar 22 23:37:32 2010 MottUpdateABSLPLL reconstructed

 

We have managed to lock the PLL to reasonable stability. The RF input is attenuated by 26 dBm and the beat signal locks very close to the carrier of the marconi (the steps on the markers of the spectrum analyzer are coarse).  We can use the marconi and the local boost of the pdh box to catch the lock at 0 gain.  Once the lock is on, the gain can be increased to stabilize the lock.  The locked signals are shown in the first photo (the yellow is the output of the mixer and the blue is the output to the fast input of the laser.  If the gain is increased too high, the error signal enters an oscillatory regime, which probably indicates we are overloading the piezo.  This is shown in the second photo, the gain is being increased in time and we enter the non-constant regime around mid-way through.

Tomorrow I will use this locked system to measure the PZT response (finally!).

Attachment 1: 2010-03-22_23.14.00.jpg
2010-03-22_23.14.00.jpg
Attachment 2: 2010-03-22_23.24.50.jpg
2010-03-22_23.24.50.jpg
  2698   Tue Mar 23 00:31:51 2010 KojiUpdateIOOMC realigned

This is the first touch to the MC mirrors after the earthquake on 16th.

  • I made an aluminum access connector so that we can work on the MC even the door is open. We still can be able to open the aluminum tube. The photos are attached. Steve, could you please look it at a glance whether the seal is enough or not.
  • MC resonances were flashing. Align MC2 and MC3 so that we have many TEM00s.
  • Found c1vmesus2 gone mad. Restarted remotely according to the wiki entry. 
  • Reset the MC coil output matrix to 1. (Previously, balance was adjusted so that A2L was minimized.)
  • Excite MC2 Pitch/Yaw at 8 and 9 Hz, looking at the peaks in the MC-MCL output. Move MC2 Pitch/Yaw so that the peak
    is reduced. (*)
  • MC1/MC3 were aligned so that we get the maximum transmission (or minimum reflection). (**)
  • Repeat (*) and (**)

So far, I have aligned in Yaw such that the yaw peak is minimized.

Attachment 1: IMG_2346.jpg
IMG_2346.jpg
Attachment 2: IMG_2347.jpg
IMG_2347.jpg
  2699   Tue Mar 23 09:37:36 2010 steveUpdateIOOvac envelope has to be sealed as antproof for overnight

Quote:

This is the first touch to the MC mirrors after the earthquake on 16th.

  • I made an aluminum access connector so that we can work on the MC even the door is open. We still can be able to open the aluminum tube. The photos are attached. Steve, could you please look it at a glance whether the seal is enough or not.
  • MC resonances were flashing. Align MC2 and MC3 so that we have many TEM00s.
  • Found c1vmesus2 gone mad. Restarted remotely according to the wiki entry. 
  • Reset the MC coil output matrix to 1. (Previously, balance was adjusted so that A2L was minimized.)
  • Excite MC2 Pitch/Yaw at 8 and 9 Hz, looking at the peaks in the MC-MCL output. Move MC2 Pitch/Yaw so that the peak
    is reduced. (*)
  • MC1/MC3 were aligned so that we get the maximum transmission (or minimum reflection). (**)
  • Repeat (*) and (**)

So far, I have aligned in Yaw such that the yaw peak is minimized.

 This seal is good for daily use- operation only. The IFO has to be sealed  with light metal doors every night so ants and other bugs can not find their way in.

Our janitor Kevin is mopping the hole IFO room floor area with 5%  ant killing solution in water in order to discourage bugs getting close to our openings of the vented chamber.

You may be sensitive to this chemical too.  Do not open chamber till after lunch.

Attachment 1: pc3.JPG
pc3.JPG
Attachment 2: pc4.JPG
pc4.JPG
  2700   Tue Mar 23 09:55:20 2010 KojiUpdateIOOvac envelope has to be sealed as antproof for overnight

Roger.

Quote:

 This seal is good for daily use- operation only. The IFO has to be sealed  with light metal doors every night so ants and other bugs can not find their way in.

 

ELOG V3.1.3-