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ID Date Author Type Category Subjectdown
  352   Mon Mar 3 13:58:10 2008 steveUpdateComputers RFM Network are down
The CODAQ_RFNETWORK are down, except C1SUSVME & AWG
  353   Mon Mar 3 19:34:40 2008 ranaUpdateComputers RFM Network are down

Quote:
The CODAQ_RFNETWORK are down, except C1SUSVME & AWG

All of the FE machines were found to be down this afternoon. I called Alex and he suggested several
things which didn't work (restart EPICS tasks, power cycle RFM switch, etc.).

Then he suggested that I go around and power cycle every crate!!! And that sometimes the order of this
matters!!! I think he was just recording this conversation so that he could have a laugh by playing it on Youtube.

However, power cycling all of the FE crates seemed to work. Alex's theory is that 'something goes bad in the
RFM cards sometimes'.

Its all green now.
  7566   Wed Oct 17 08:30:49 2012 SteveUpdateSUS PTICH damping needed

Quote:

Quote:

  [Koji, Steve, Den]

TT alignment is fine, yaw damping is satisfactory, pitch damping is slow. We might want to add magnets to the mirror and attach blades to the frame for pitch edge current damping.

We are moving towards electronics testing.

Atm1,  TT 1.5" high adaptor base will be back from the shop in 10 days.

Atm2,  There is no PITCH damping, YAW edie current damping works well at 0.5 mm gap

Atm3,  Adjustable Al -disc that contains a small magnet is purely designed.

We have to come up with a solution to have damping in PITCH

 Pitch damping solution needed! It should be in the machine shop already.

  13538   Fri Jan 12 10:26:24 2018 SteveUpdatePSL PSL shelf work schedule

Measurements for good fit were made. The new shelf will be installed on next Tuesday at 2pm

The reference cavity ion pump is in the way  so the cavity will be moved 5" westward. The shelf height space will be 10"  Under shelf working height 18" to optical table.

Quote:

I have just received the scheduling of the PSL self work for tomorrow. Gautam and I agreed that if it is needed I will shut the laser off and cover the hole table with plastic.

 

  13549   Tue Jan 16 11:05:51 2018 gautamUpdatePSL PSL shelf - AOM power connection interrupted

While moving the RefCav to facilitate the PSL shelf install, I bumped the power cable to the AOM driver. I will re-solder it in the evening after the shelf installation. PMC and IMC have been re-locked. Judging by the PMC refl camera image, I may also have bumped the camera as the REFL spot is now a little shifted. The fact that the IMC re-locked readily suggests that the input pointing can't have changed significantly because of the RefCav move.

 

  13551   Tue Jan 16 21:46:02 2018 gautamUpdatePSL PSL shelf - AOM power connection interrupted

Johannes informed me that he touched up the PMC REFL camera alignment. I am holding off on re-soldering the AOM driver power as I could use another pair of hands getting the power cable disentangled and removed from the 1X2 rack rails, so that I can bring it out to the lab and solder it back on.

Is anyone aware of a more robust connector solution for the type of power pins we have on the AOM driver?

Quote:

While moving the RefCav to facilitate the PSL shelf install, I bumped the power cable to the AOM driver. I will re-solder it in the evening after the shelf installation. PMC and IMC have been re-locked. Judging by the PMC refl camera image, I may also have bumped the camera as the REFL spot is now a little shifted. The fact that the IMC re-locked readily suggests that the input pointing can't have changed significantly because of the RefCav move.

 

 

  12844   Wed Feb 22 08:54:17 2017 steveUpdatePEM PSL enclousure particle count

ETMX sus damping recovered.  PSL enclousure is dusty at 20V rotation speed. Rainy days as outside condition.

Quote:

The MET#1 particle counter was moved from CES wall at ITMX to PSL enclousure south west corner at 11am.

The HEPA filter speed at the Variac was turned down to 20V from 40

This counter pumps air for 1 minute in every 20 minutes. Soft foam in bags used to minimize this shaking as it is clamped.

 

 

Attachment 1: dusty__PSL.png
dusty__PSL.png
  7568   Wed Oct 17 11:15:05 2012 DenUpdateSUS PITCH damping needed

Quote:

 

 Pitch damping solution needed! It should be in the machine shop already.

I think we can put ø2mm × 10mm long magnetic material inside 4 holes with actuation magnets. Then magnetic field on the other side of the mirror will be close to one produced by actuation magnet. Magnetic cylinder center of inertia will be in the vertical plane where mirror's center of inertia is. So this should not change alignment significantly. Eddy current dumping will be applied to the end of the magnetic cylinder opposite to the magnet using aluminium disks, we have them in the clean room.

pitch_damping.png

  7571   Thu Oct 18 02:42:38 2012 DenUpdateSUS PITCH damping needed

Quote:

 

I think we can put ø2mm × 10mm long magnetic material inside 4 holes with actuation magnets. Then magnetic field on the other side of the mirror will be close to one produced by actuation magnet. Magnetic cylinder center of inertia will be in the vertical plane where mirror's center of inertia is. So this should not change alignment significantly. Eddy current dumping will be applied to the end of the magnetic cylinder opposite to the magnet using aluminium disks, we have them in the clean room.

 I've tested this approach. As we do not have required cylinders with high magnetic permittivity, I replaced them with magnets simular to actuator magnets ø2mm × 3mm long. Using them and aluminium disks from other TT I've made a "pitch dumping" construction.

DSC_4759.JPG

Pitch Q reduced but not that much as I could expect. I did a ringdown test. 

Plots:

yaw ringdown using original construction     |  yaw ringdown with added pitch damping

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

pitch ringdown using original construction   |  pitch ringdown with added pitch damping

    yaw_nodamp_20.JPG   yaw_damped_13.JPG

pitch_nodamp_30.JPG     pitch_damped_10.JPG

 

 From this data I've estimated Q factor for yaw (135 vs 88) and pitch (192 vs 77) (original vs added pitch damping). Thess results diverges with the ones obtained by designes. They measured Q~40-50 for original construction. Pitch and yaw have 2 close resonances so this time domain method can not be very precise. I've measured the same with SR785.

yaw.pngpitch.png

In these comparison plots excitation was not the same as coils are not plugged in yet, but resonance Q factors can be compared.

 

  7583   Fri Oct 19 18:30:07 2012 DenUpdateSUS PITCH damping needed

CQuote:

 

 From this data I've estimated Q factor for yaw (135 vs 88) and pitch (192 vs 77) (original vs added pitch damping).

 I've made a more precise measurement of pitch damping using spectrum analyzer.

damp.png   pitch.png

Measurements confirm that damping using small actuation magnets reduces pitch Q by a factor of 4 and is not enough.

  7585   Sat Oct 20 01:23:56 2012 DenUpdateSUS PITCH damping needed

Quote:

Measurements confirm that damping using small actuation magnets reduces pitch Q by a factor of 4 and is not enough.

 I've tested the idea to use coils as eddy current dampers. I terminated them with a wire and measured Q factor during the ringdown test. Sadly, I did not see any significant damping and Q was ~150. We need stronger magnets if we want eddy current dumping down to Q~1.

P1010059.jpg      P1010060.jpg    P1010058.jpg

  7586   Sat Oct 20 20:37:55 2012 DenUpdateSUS PITCH damping needed

Quote:

 

 We need stronger magnets if we want eddy current dumping down to Q~1.

 I've inserted 10mm * 10mm magnets to the 4 corner holes on the front side of the mirror frame according to actuation magnets polarity. I realigned TT and measured Q factor for pitch and yaw, it was 5-10.

DSC_4778.JPG     pitch.JPG   yaw.JPG

 

I was able to do it for 1 TT only, because others have smaller (~0.1 mm) hole diameter and magnets can't go inside. I tried to warm holes up to 850 F but still was not able to insert a magnet.

DSC_4776.JPG

  7588   Mon Oct 22 11:26:12 2012 ranaUpdateSUS PITCH damping needed

 

Too bad - I thought it would at least give a little damping. Since we want the viscous-like energy loss to be ~49x larger, we need to have the field modulation in the damper (not dumper) increase by ~7.

  7593   Tue Oct 23 01:46:53 2012 DenUpdateSUS PITCH damping needed

Quote:

 

Too bad - I thought it would at least give a little damping. Since we want the viscous-like energy loss to be ~49x larger, we need to have the field modulation in the damper (not dumper) increase by ~7.

 I've made SolidWorks models of damping bracket and eddy current disk. They will me manufactured and used instead of old ones. New bracket will be mounted in exactly the same place where the old one was. Drawings might not be complete but all dimensions are in the models so we can fix drawing tomorrow before going to machine shop.

I think we can use ring magnets for passive damping. Then we won't have the vent problem. I've found some at K&J Magnetics, we can get them any time. Magnets are Ni-Cu-Ni (fine for vacuum?) Diameter is 3/8'' with advertised tolerence 0.004'', so they should fit the holes.

Attachment 1: Mirror_Holder_ECD_NEW_DRAWING.PDF
Mirror_Holder_ECD_NEW_DRAWING.PDF
Attachment 2: TT_DAMPING_DRAWING.PDF
TT_DAMPING_DRAWING.PDF
  7598   Tue Oct 23 17:12:30 2012 DenUpdateSUS PITCH damping needed

 Koji and Steve pointed out that previous design  of a damping bracket was a bit complicated to manufacture. So I made it simpler and also added a tap hole for original yaw damping. We'll give drawing to Mike in the machine shop tomorrow morning.

I've purchased K&J magnets for eddy current damping, they should be here in 2 days. 

Attachment 1: simple_drawing.PDF
simple_drawing.PDF
  7602   Tue Oct 23 18:18:29 2012 JenneUpdateSUS PITCH damping needed

Quote:

Quote:

 

Too bad - I thought it would at least give a little damping. Since we want the viscous-like energy loss to be ~49x larger, we need to have the field modulation in the damper (not dumper) increase by ~7.

 I've made SolidWorks models of damping bracket and eddy current disk. They will me manufactured and used instead of old ones. New bracket will be mounted in exactly the same place where the old one was. Drawings might not be complete but all dimensions are in the models so we can fix drawing tomorrow before going to machine shop.

I think we can use ring magnets for passive damping. Then we won't have the vent problem. I've found some at K&J Magnetics, we can get them any time. Magnets are Ni-Cu-Ni (fine for vacuum?) Diameter is 3/8'' with advertised tolerence 0.004'', so they should fit the holes.

 Den mentioned that the disks will have threaded holes, and that he has made a note to that effect on the paper copy of the drawing that he will bring to Mike at the shop.  Also, all threaded holes in the new plate are marked on the paper copy.

  7604   Wed Oct 24 01:02:10 2012 KojiUpdateSUS PITCH damping needed

Wow... This is even more complicated than the original "Y" design...

  7640   Mon Oct 29 18:14:55 2012 DenUpdateSUS PITCH damping needed

 

 We've received all parts that we need for eddy current damping. I've made an estimate of Q with dirty tip-tilt. It looks fine (Q~1)

We need to check ring magnets for vacuum compatibility. Bob start baking on Friday.

DSC_4787.JPG     DSC_4791.JPG

  5139   Mon Aug 8 13:24:00 2011 steveMetaphysicsTreasure Monday morning

Quote:

Just a reminder that a film crew will be here Monday morning, filming Christian Ott for some Discovery channel show.

They are slated to be here from 8am to 12:30pm or so.  They will take a couple of shots inside the lab, and the rest of the filming should be of Christian in the control room (which they will "clean up" and fit with "sexy lighting").  I will try to be here the whole time to oversee everything.

Konecrane Fred was early this morning. He diagnosed the ETMY crane horizontal drive gear box dead and left just before the film crew showed up.

New gear box should be here by the end of this week for installation.

The lab air quality is high ~20,000 counts of particles of 0.5 micron.  Keep an eye on this before you open the chamber.

Attachment 1: P1080147.JPG
P1080147.JPG
  7460   Tue Oct 2 07:45:49 2012 SteveUpdateSUS MC2 & PRM sus damping restored
  7466   Wed Oct 3 07:41:23 2012 SteveUpdateSUS MC2 sus damping restored

This is the third morning in a row that the MC2 was tripped.  Would you look at it Koji?

  7473   Wed Oct 3 23:24:05 2012 KojiUpdateSUS MC2 sus damping restored

Quote:

This is the third morning in a row that the MC2 was tripped.  Would you look at it Koji?

This may be cause by the impact of crazy WFS signal after the lock loss.
The auto locker is not fast enough to shut the WFS down before the mirrors are kicked.

Jenne and I discussed the issue and agreed that this can be solved by implementing
the same triggering algorithm as the LSC triggers.

Give us a bit more time to work on this.

  7496   Sun Oct 7 15:05:42 2012 DenUpdateSUS MC2 sus damping restored

Quote:

This is the third morning in a row that the MC2 was tripped.

 MC2 was tripped again. I think the answer is that watchdog's critical value was too small C1:SUS-MC2_PD_MAX_VAR = 10, so seismic could trip MC2. I've changed the value to 100.

mc2.png

  10428   Mon Aug 25 09:56:21 2014 SteveUpdateIMC IMC WFSs upgrade

 

 The Napa earth quake magnitude 6 did not have any effect on the suspensions.

 The Goy phase upgrade was done nicely. The IOO pointing did not change. Credit owned to Nick and Andres.

  IFO is locked right on.

Attachment 1: eq6Mnapa.png
eq6Mnapa.png
  2585   Wed Feb 10 16:27:47 2010 steveConfigurationGeneral IFO beam heights

IN VACUUM beam heights are ALL 5.5"  This is measured from the top of the optical table to the center of all TMs, mirrors and other optical components. This beam is ~36" above the floor.

PSL (inside of enclosure) main-output  beam: PMC, MZ, RC and ISS  are at 3" heights. IOO Angle & Position, MC-Trans and RFAM qpds are at 4"

ALL OTHER beam heights at atmosphere and  different ISCT (interferrometer sensing, control optical table)s are at 4"

 

 

  8834   Fri Jul 12 09:00:10 2013 SteveUpdateGeneral Halogen illumination cables disconnected

Alex and Steve,

Old halogen chamber illuminator cabling disconnected and potenciometer board removed at 1Y1 in order to give room for pd calibration fibre set up.

Attachment 1: 1Y1oldilluminatersDisconnected.jpg
1Y1oldilluminatersDisconnected.jpg
  8835   Fri Jul 12 12:30:47 2013 manasaUpdateGeneral Halogen illumination cables disconnected

Quote:

Alex and Steve,

Old halogen chamber illuminator cabling disconnected and potenciometer board removed at 1Y1 in order to give room for pd calibration fibre set up.

 During the process, they had also removed the power cable to the ITMY camera. Steve and I fixed this...so the camera is back.

  525   Fri Jun 6 16:47:04 2008 josephbConfigurationCameras GC650 scatter images of 1064nm light
Took images similar to the scattered light images from earlier, except with the CCD GC650 camera. The first three attached plots are an average of all 200 images, an average of the first 100 and then an average of the last 100 images.

They show no definite structure. The big red blob which changes with time may be a brighter reflection, although it virtually the same type of setup as the GC750 images.

To do this properly, I should grab a short focal length lens and simply blow up the beam to a size greater than the detector area and simply fix both cameras looking into.

The last set of plots are mean and standard deviation plots from a previous set of runs on 5/29/08 with the GC750 and GC650 running at the same time. The GC650 was receiving approximately 33% of the total power and GC750 was receiving 66% (in otherwords a factor of 2 more).
Attachment 1: GC650_scatter_200.pdf
GC650_scatter_200.pdf
Attachment 2: GC650_scatter_100a.pdf
GC650_scatter_100a.pdf
Attachment 3: GC650_scatter_100b.pdf
GC650_scatter_100b.pdf
  12226   Wed Jun 29 08:20:04 2016 SteveUpdateSUS First Contact shelf life
We'll follow LIGO policy:
Our policy is to use first contact within 1 year of purchase for use in the interferometers.  For inspection use I am comfortable with out-of-date use.

GaryLinn offered their indate First Contact for use.

 

  8416   Thu Apr 4 17:23:05 2013 SteveUpdate40m Upgrading ETMY optical table & enclosure is ready for optics

Quote:

 Enclosure is at the east end. It has it's bottom o-ring in place. It will be ready for optics tomorrow around 5pm

I have to shim out the enclosure, finish leveling the table and cut surgical tubing O-ring for the top.

 

 Glued surgical latex tubing with super glue into O-ring shape. The existing in place tubing K-100, OD 0.125" (actual size 0.140"), wall 0.031", ID 0.062".

I have just found out that tolerances on tubing OD are + - 0.026" by the manufacturer. I'm getting larger tubing for better fit.

The table is ready for optics.

Things left to do:

1, finalize o-ring size  2, finish cable feedthrough  3, finalize window connection 4, IR-Thermashield strips for bridge sides 5, replace bridge support post with solid one

 

  8472   Mon Apr 22 17:43:09 2013 SteveUpdate40m Upgrading ETMY optical table & enclosure is ready for optics

Quote:

Quote:

 Enclosure is at the east end. It has it's bottom o-ring in place. It will be ready for optics tomorrow around 5pm

I have to shim out the enclosure, finish leveling the table and cut surgical tubing O-ring for the top.

 

 Glued surgical latex tubing with super glue into O-ring shape. The existing in place tubing K-100, OD 0.125" (actual size 0.140"), wall 0.031", ID 0.062".

I have just found out that tolerances on tubing OD are + - 0.026" by the manufacturer. I'm getting larger tubing for better fit.

The table is ready for optics.

Things left to do:

1, finalize o-ring size  2, finish cable feedthrough  3, finalize window connection 4, IR-Thermashield strips for bridge sides 5, replace bridge support post with solid one

 

 I'm working on to improve the quality of the enclosure.

The short comings are: more cable feedthroughs needed, latches to anchor top covers air tight and posts to support bending bridges.

Red triangles are compression latches at 10 places to hold the top air tight on surgical tubing

Green lines represent 4  posts of Al 1" OD to support the covers and maximize their eigenfrequencies.

Black crosses are 4 spring loaded push-bottom quick release pins to anchor the top covers to the bridges. This connection will  not be air tight.

(quarter-turn wing head fastener have the same problem) I'm thinking of some solution to minimize the leak.    

Violet _ steel plate (1" wide, 15" long, 0.125" thick)  between the two posts will anchor the quick release pins and make bridge rigid.

Blue rectangle is an other cable feedthrough exiting on the chamber side.

Planning to substitute window with soft - air tight ( Aluminized thin wall hose )  connection to vacuum view port where white circle is representing the Al adaptor ring.

Updated after Wednesday meeting 4-24-2013

 

Attachment 1: more2.jpg
more2.jpg
  13776   Fri Apr 20 16:25:08 2018 SteveUpdateWiki ETMX table layout uploaded to wiki

ETMX table layout uploaded with beam paths to the wiki.   laugh

  12218   Tue Jun 28 09:14:27 2016 SteveUpdateSUS ETMX optics preparation to be rehanged

Given the effect on the contrast defect, the consensus at the meeting Wednesday 6-22  was that we should continue to use the existing ETMX optic. 

 
Does this imply that we can simply:
  • Vent
  • Remove the current ETMX suspension, and optic from the suspension
  • Replace the standoffs (and guide rod if necessary), leaving the current magnets in place
  • Re-suspend on the current, existing suspension, with new wire clamps
That is, if we are keeping the current optic, do we gain anything by replacing the whole suspension? Is there any reason to remove and replace magnets? (The wire clamps do need to be replaced, as a groove forms when they are installed.)
 
This could allow us to vent and execute this whole thing sooner. 
 
-Eric Q.
...............................
Yes, I think this is a reasonable approach. Besides the wire standoffs and wireclamps, the only other problem might by a worn groove in the top piece of the suspension (not the clamp piece, but the piece that the clamp holds the wire up against).
 
How about use the current ETM, but put it into the new suspension body with new wire standoffs?
 
Quote:

D Location

Number on

Drawing

 

Component

Name

 

 Baked Clean

 Pieces Needed

 

Pieces

In Stock

(on tower )

Notes
         
31,20,19,13 viton tips   not cut yet baked material in stock
30 6-32x0.75" stops 4 (4)  
29 steel music wire 0.017" not baked on roll  needs good wipes
28  1/4 "washer 4 (4)  
27 lock washer 4 50 install
26 Ag plated 1/4-20x1.25 4 (4)  
25 Ag plated1/4-25x.75 & not plated 20 (20)  
24 SS 4-40x.5 2 (2)  
23 SS 4-40x.38 4 (4)  
22 spring plunger 4+2 (4+2)  
         
         
18 magnets, 1.9mm od, length 3.2 mm 5 ~30 not coated, rusty buy Ni coated ones for future use
17 guide rod, 0.635 mm od, 3.3 mm 3 6 Al
16 wire standoff, 1 mm od, 4.8 mm 2 2 Al and ruby (ruby groove not centered)
15 short OSEMs 5 6  
14 spare ETMX in 40m wiki 1 1  confirmed in cabinet
         
12 dumbbell standoff 5 6  
11 Al stiffening plate 1 (1)  
10 wire clamp B in sus block 2 (2)  
9 wire clamp A 1 (1)  
8-7 lower clamp for lifting optics 2 (2)  
6 upper clamp to hold down optic 1 (1)  
5-4 left-right side of tower  1 ea (1ea)  
3 tower base 1 (1)  
2 sus block 1 (1)  
1 lower and upper OSEM holders 1ea (1ea)  
         
48 sandind fixture for magnet&dumbbell      
45 magnet-dumbbell assemblly fixture 1 1  
43 guide rod gluing fixture     shipped from LOH .... D000335...needs cleaning
         
  First contact   3-15-2013 purchase check expiration date OK
  FCPEEK peeler ring disk for TM cleaning 10 front,10 back side  have sheets only 32&19mm ID punches ordered
  GordonBrush custom for LIGO optical cleaning ~5 1 (3/8wide nylonSS) more from Calum available
  EP30-2 epoxy have  have expiration date 9-24-2016

NOT finished, last edited 6-28

 

Attachment 1: nylonFCss.jpg
nylonFCss.jpg
  12890   Fri Mar 17 10:47:16 2017 SteveUpdateOptical Levers ETMX oplev laser replaced

JDSU 1103P. sn T8070866, made March 2007, output power 2.7 mW,  on pd 17,750 counts,

GV 17 March 3pm: I found the Innolight NPRO was off when I walked down to the X end earlier, possibly was accidentally tripped during the Oplev laser replacement. I turned it back on.

Quote:

 

Quote:

ETMX oplev laser is dead. It will be replaced this after noon. Sus damping recovered.

This 3 years old HeNe [ JDS 1103P, sn 351889 ]  has been dying for some time or just playing possum at age 1,126 days

I did not replace the ETMX oplev laser because I was unable to bring up the the C1ASC_ETMX_OPTLEV_SERVO  medm screen on laptops.

 

  12229   Wed Jun 29 16:02:29 2016 SteveUpdateSUS ETMX beam baffle

In the attached photo from 2012, one can see the installed black glass baffle. According to the drawings (LIGO-DNNNXXX) this one has a clear aperture of 40 mm.

In (someplace ?) we have clean baffles with a 50 mm aperture which can be installed during this vent. In order to be more conservative, let us choose to swap these out for all 4 test masses during the upcoming vent using the green laser as an alignment guide, as Koji described at today's lunch meeting.

They are located at the top of E1 drawer cabinet

Attachment 1: IMG_1608.JPG
IMG_1608.JPG
  11980   Mon Feb 8 09:37:07 2016 SteveUpdateSUS EQ 3.9m

No sign of damage

 

Attachment 1: EQ3.9mSimmierCa.png
EQ3.9mSimmierCa.png
  12199   Mon Jun 20 09:36:10 2016 SteveUpdateSUS EQ 3.1 m Big Bear Lake, CA

No suspention lost damping.

 

Attachment 1: eq3.1BigBearLakeCA.png
eq3.1BigBearLakeCA.png
  12165   Fri Jun 10 09:52:51 2016 SteveUpdateSUS EQ 5.2 mag Borego Spring

EQ  5.2 mag at Jun 10, 8:04 am UTC, Borego Spring, CA  ~150 mi away.........no obvoius damage, damping restored, MC is locking, arms are flashing

 

Attachment 1: 5.2mBoregoSpring.png
5.2mBoregoSpring.png
Attachment 2: eqBSs.png
eqBSs.png
  1548   Tue May 5 11:44:33 2009 robUpdateLocking DARM response

Here's the RF DARM optical response, on the anti-spring side, from optickle. Note that for the f1 sideband, changing the demod phase mostly adjusts the overall gain, while for the f2 sideband a change in demod phase alters the shape of the response. This is the quadrature-selecting power of using a single RF sideband as a local oscillator.
Attachment 1: DARMtf_nospring.png
DARMtf_nospring.png
Attachment 2: DARMtf_demodphases.png
DARMtf_demodphases.png
  9709   Mon Mar 10 21:13:43 2014 nicolasSummaryLSC Composite Error Signal for ARms (2)

In order to better understand how the composite signal would behave in the presence of noise, I decided to do a simple analysis of the cavity signals while sweeping through resonance.

My noise model was to just assume that a given signal has some rms uncertainty (error bars) and use linear error propagation to propagate from simple signals to more complicated ones.

I used the python package uncertainties to do the error propagation.

I assumed that the ALS signal, the cavity transmission, and the cavity PDH error signal all have some constant noise that is independent of the cavity detuning. Below is a sweep through resonance (x axis is cavity detuning in units of radians).

rawsigs.png

The shaded region represents the error on each signal.

Next I calculated the 'first order' calculated error signals. These being a raw PDH, normalized PDH, an inverse square root trans, and the normal ALS again. I tuned the gains so they match appropriately.

Here, one can see how the error in the trans signal propagates to the normalized and trans signals and becomes large are the fractional error in the trans signal becomes large.

errorsigs.png

Next I did some optimization of linear combinations of these signals. I told the code to maximize the total signal to noise ratio, while ensuring that the overall signal had positive gain. I did this again as a function of the cavity detuning.

Each curve represents the optimized weight of the corresponding signal as a function of detuning.

optimalweights.png

So this is roughly doing what we expect, it prefers ALS far from the resonance, and PDH close to the resonance, while smoothly moving into square root trans in the middle.

It's a little fake, but it gives us an idea of what the 'best' we can do is.

Finally I used these weights to recombine the signals into a composite, to get an idea of the noise of the overall signal. At the same time, I plot the weighting proposed by Koji's mathematica notebook (using trans and 1-trans, and a hard switch to ALS).

compositenoise.png

So as one can see, at least for the noise levels I chose, the koji weighting is not much worse than the 'optimal' weighting. While it is much simpler.

The code for all this is in the svn at 40mSVN/nicolas/workspace/2014-03-06_compositeerror

  11719   Tue Oct 27 10:08:12 2015 SteveUpdateVAC CC vacuum gauges

CC1 and CC2 are working again. Why did they start working  again ?

 

Attachment 1: gauges_5y_vs_8d.png
gauges_5y_vs_8d.png
Attachment 2: 13.9yCC1&4.png
13.9yCC1&4.png
  11349   Tue Jun 9 10:57:12 2015 SteveUpdateSUS BS oplev laser tuned

Lenses removed from oplev beam path at elog entry 11246

 

Attachment 1: 100dBStrend0425.png
100dBStrend0425.png
Attachment 2: 18dBSdrift.png
18dBSdrift.png
  14173   Tue Aug 21 09:16:23 2018 SteveUpdateWiki AP table layout 20180821

 

 

Attachment 1: 20180821.JPG
20180821.JPG
  13785   Tue Apr 24 15:59:23 2018 SteveUpdateWiki AP table layout 20180328
Quote:

ETMX table layout uploaded with beam paths to the wiki.   laugh

The pdf file is uploaded into the wiki.

Attachment 1: DSC00668AP20180328.png
DSC00668AP20180328.png
  6263   Thu Feb 9 16:46:02 2012 steveUpdateSUS ALL oplev YAW transfer functions

Quote:

SUS- BS, ITMX, ITMY, PRM, SRM, ETMX & ETMY_OLPIT transfer funtion with sine wave excitation 0.1 amplitude:

 

OL_YAW transfer functions are here.

 I had two PHDs helping me to overlap the EXML files in DTT. We failed. This job requires professorial help.

Attachment 1: BS-OLYAW.1ampl.png
BS-OLYAW.1ampl.png
Attachment 2: ITMX-OLYAW.1ampl.png
ITMX-OLYAW.1ampl.png
Attachment 3: ITMY-OLYAW.1ampl.png
ITMY-OLYAW.1ampl.png
Attachment 4: PRM_OLYAW.1.png
PRM_OLYAW.1.png
Attachment 5: SRM_OLYAW.1ampl.png
SRM_OLYAW.1ampl.png
Attachment 6: ETMX-OLYAW.1ampl.png
ETMX-OLYAW.1ampl.png
Attachment 7: ETMY-OLYAW.1ampl.png
ETMY-OLYAW.1ampl.png
  6259   Tue Feb 7 16:30:46 2012 steveUpdateSUS ALL oplev PIT transfer functions

SUS- BS, ITMX, ITMY, PRM, SRM, ETMX & ETMY_OLPIT transfer funtion with sine wave excitation 0.1 amplitude:

 

Attachment 1: BS_PIT.png
BS_PIT.png
Attachment 2: ITMX_PIT.png
ITMX_PIT.png
Attachment 3: itmy_pit.png
itmy_pit.png
Attachment 4: PRM_PIT.png
PRM_PIT.png
Attachment 5: SRM_PIT.png
SRM_PIT.png
Attachment 6: ETMX_PIT.png
ETMX_PIT.png
Attachment 7: ETMY_PIT2.png
ETMY_PIT2.png
  13964   Thu Jun 14 15:24:32 2018 SteveUpdatePEM ADC DAC In Line Test Boards are in

We have 6 of these boards now in cabinet E7

Quote:

I wired all 32 channels going to the AA board directly to the ADC as described in the previous log. However, instead of using the old AA board and bypassing the whole circuit, I just used a breakout board as is shown in the first attachment. I put the board back in the rack and reconnected all of the cables.

The seismic BLRMs appear to be working again. A PSD of the BS seismometers is shown in attachment 2. Tomorrow I'll look at how much the ADC alone is suppressing the common mode 60 Hz noise on each of the channels.

Steve: 5 of ADC DAC In Line Test Boards [ D060124 ] ordered. They should be here within 10 days.

 

Attachment 1: ADC_DAC_in_(1).JPG
ADC_DAC_in_(1).JPG
  1486   Wed Apr 15 11:25:21 2009 steveConfigurationVAC RGA cal completed

Quote:

Vacuum normal valve condition was changed to accommodate SRS-RGA calibration.

 

The annulus valves were closed to free TP3 to pump on the RGA
VM1 was closed to isolate the RGA from the IFO.
 
 
VM3 opened to TP3.
 
This condition is called back ground (BG) mode. It is where we can calibrate and see the RGA background without the IFO.

 Vacuum valve configuration is back to VACUUM NORMAL  condition. RGA  calibration  completed.

RGA  scan attached is the backgroud of the rga with std cal leak open, sn 08581

Krypton at amu 84 and Argon at amu 40 are the cal signals.

 

Attachment 1: rga-090415-bg-d7-cald2.png
rga-090415-bg-d7-cald2.png
  481   Thu May 15 16:24:18 2008 josephbSummaryCameras 
The GC750 camera is currently looking at a very small pickoff of the PSL output (transmission of a Y1-1037-45-S mirror). The plan is to take images tomorrow with it and the GC650 from the same spot and do comparisons.

For those interested, the camera can be run with two codes, from mafalda. Use ssh -X mafalda to login, to allow the live stream to work with the SampleViewer code. The codes can be found in:

/cvs/cds/caltech/target/Prosilica/40mCode/Snap

and

/cvs/cds/caltech/target/Prosilica/bin-pc/x86/SampleViewer

Type Snap --help for a list of options for that program. Click the circle looking thing in SampleViewer to start the live stream. Note only 1 of the two programs can be running at a time, and the only way to change settings (such as exposure length) is with Snap at the moment.
  492   Thu May 22 11:25:19 2008 josephbConfigurationComputers 
One of the new Netgear Prosafe 24 port switches was mounted in the 1X4 rack,, roughly in the middle, away from the top and bottom rack mounted electronics. At the moment, its IP has been set to 131.215.113.250, gateway 131.215.113.2 (which is what I saw as the only listed gateway on linux1 using route -n) and mask 255.255.255.0.

I'm planning to set the next three IP address for the switches as *.251, *.252 and *.253, which don't look to have been used yet.
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