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ID Date Author Type Categoryup Subject
  12036   Wed Mar 16 15:36:03 2016 SteveUpdateSUSwire standoff test cut

Ruby wire standoff 1 mm od. with V-groove test cut. SOS sus wire 0.0017" od. is in the background.
 

Attachment 1: 0182_-_20160316_135935.png
0182_-_20160316_135935.png
  12037   Wed Mar 16 16:02:40 2016 KojiUpdateSUSwire standoff test cut

It looks almost OK, but we need a bit sharper picture for both the groove and thw wire.

Attachment 1: ruby.png
ruby.png
  12038   Fri Mar 18 11:04:56 2016 SteveUpdateSUSinverted pendulum

Kate Dooley picked up this item today.

Attachment 1: invPeng.jpg
invPeng.jpg
  12039   Mon Mar 21 10:07:45 2016 SteveUpdateSUSETMX enclosure update

The enclosure top piece in the middle is still in the machine shop.

The carpenter who helps in the built just left for one week vacation.

The unit will be ready  on April 1

I'd prefer doing the installation with the enclosure on the new table.

It's the only way to minimize the resonances of the enclosure with shimming.

Attachment 1: ETMXenclosure.jpg
ETMXenclosure.jpg
  12050   Mon Mar 28 08:30:09 2016 SteveUpdateSUSPRM damping restored

Recent  EQ 4.8 mag San Felipe, Mexico trips PRM sus damping.

PRM damping restored. PMC locked.

Attachment 1: shaking.png
shaking.png
  12062   Tue Apr 5 08:55:51 2016 SteveUpdateSUSlocal EQ 3.1m

Local earth quake 3.1 magnitude in Valencia, Ca did not trip our suspensions.

 

Attachment 1: eq3.1Valencia.png
eq3.1Valencia.png
  12071   Tue Apr 12 09:14:57 2016 SteveUpdateSUSRuby wire - v - groove cut pictures

The ruby wire standoff V groove cuts are looking good.

I will request free sample of  sapphire prizm where one side would have SOS's R cylindrical surface.

The present plan to have the v-groove on this prism.

 

Attachment 1: Sapphire_prism_wire_standoff.JPG
Sapphire_prism_wire_standoff.JPG
  12088   Mon Apr 25 11:07:06 2016 SteveUpdateSUSspare SOS tower

Earth quake stops need viton tips.

Wirestandoffs are still aluminum.

Attachment 1: ETMXreplacment.jpg
ETMXreplacment.jpg
  12092   Wed Apr 27 09:45:56 2016 ranaUpdateSUSspare SOS tower

Bah, we need ruby slippers for all future suspensions. Prism with curved backside and smooth grooves.

No aluminum, no cry.

Quote:

Earth quake stops need viton tips.

Wirestandoffs are still aluminum.

 

  12125   Mon May 23 10:55:49 2016 steveSummarySUSITMX oplev laser replaced

 

      May 23, 2016             ITMX dead He/Ne laser sn P845648 replaced after 1062 days [2.9 yrs] by 1103P, sn P859884, with output  2.6 mW, nicely round beam quality at 15 meters.

                                                                                                                                                    Power just before viewport 1 mW,  returning light on qpd 154 microW =  7,500 counts

 

Attachment 1: ITMXoplev.png
ITMXoplev.png
  12126   Mon May 23 15:51:32 2016 steveSummarySUSoplev laser summary updated

 

Quote:

 

Quote:

 

Quote:

 

                  2005              ALL oplev servos use Coherent DIODE LASERS # 31-0425-000, 670 nm, 1 mW

    Sep. 28, 2006              optical lever noise budget with DC readout in 40m,  LIGO- T060234-00-R, Reinecke & Rana

    May  22, 2007              BS, SRM & PRM  He Ne 1103P takes over from diode

    May  29, 2007              low RIN He Ne JDSU 1103P selected, 5 purchased sn: T8078254, T8078256, T8078257, T8078258 & T8077178 in Sep. 2007

    Nov  30, 2007               Uniphase 1103P divergence measured

    Nov. 30, 2007               ETMX old Uniphase 1103P  from 2002 dies: .............., running time not known......~3-5 years?

    May 19, 2008               ETMY old Uniphase 1103P from 1999 dies;.....................running time not known.....~    ?

    Oct.  2, 2008                ITMX & ITMY are still diodes, meaning others are converted to 1103P earlier

 

                     JDSU 1103P were replaced as follows:

   May 11, 2011                ETMX replaced, life time 1,258 days  or 3.4 years

   May 13, 2014               ETMX , LT 1,098 days or 3 y

   May 22, 2012               ETMY,  LT 1,464 days or  4 y

   Oct.  5, 2011                BS & PRM, LT 4 years,  laser in place at 1,037 days or 2.8 y

   Sep. 13, 2011               ITMY  old 1103P &    SRM    diode laser replaced by 1125P  ..........old He life time is not known, 1125P in place 1,059 days or 2.9 y

   June 26, 2013              ITMX 622 days or 1.7 y    note: we changed because of beam quality.........................laser in place 420 days or 1.2 y

 

  Sep. 27, 2013               purchased 3 JDSU 1103P lasers, sn: P893516, P893518, P893519 ......2 spares ( also 2 spares of 1125P of 5 mW & larger body )

 

      May  13, 2014             ETMX,  .............laser in place 90 d

      May  22, 2012             ETMY, 

     Oct.  7,  2013             ETMY,  LT  503 d  or  1.4 y............bad beam quality ?

     Aug. 8,  2014              ETMY,  .............laser in place   425 days  or  1.2 y

 

      Sept. 5, 2014              new 1103P, sn P893516  installed at SP table for aLIGO oplev use qualification

     

           May 23, 2016             ITMX dead laser sn P845648 replaced after 1062 days [2.9 yrs] by 1103P, sn P859884, with output output  2.6 mW, nicely round beam quality at 15 meters.

Attachment 1: oplSum.png
oplSum.png
  12128   Tue May 24 10:21:36 2016 ericqSummarySUSITMX Oplev loops

I did a quick measurement of the ITMX oplev loops, both pitch and yaw have about the same upper UGF as previous measurements with the previous laser; about 4 Hz. 

  12133   Wed May 25 08:32:55 2016 SteveUpdateSUSlocal EQ 3.5m

Local EQ 3.5 mag  at 2:28 UTC May 24, 2016 Rancho Cucamonga, Ca.....no damage

 

Attachment 1: 3.5Cucam.png
3.5Cucam.png
Attachment 2: local3.5cucam.png
local3.5cucam.png
  12144   Wed Jun 1 15:01:56 2016 SteveUpdateSUS wire standoffs update

There are some issues with 5 mm sapphire prism Atm5. It will cause  interference between one of the prisms and the Side OSEM.

Here are some drawings to see the issues with larger wire standoff.

The 2 mm prism will work.with a 1 mm longer dumbell.

Quotes requested from http://photomachining.com/laser-micromachining-photomachining-contact.html and http://www.optocity.com/ 

 

 

Attachment 1: 06011603.PDF
06011603.PDF
Attachment 2: 06011602.PDF
06011602.PDF
Attachment 3: sapphire_stand_off_v2.pdf
sapphire_stand_off_v2.pdf
Attachment 4: side_OSEM_ETMY.jpg
side_OSEM_ETMY.jpg
Attachment 5: 5p2wsf.png
5p2wsf.png
  12146   Thu Jun 2 16:35:44 2016 KojiUpdateSUS wire standoffs update

Gap of the prism from the mirror

Sag: s = R(1-Cos[ArcSin[d/2/R]])

- Mirror curvature sag for 2mm prism (R=37.75mm): s=13um

- Minimum gap: 20um => s=33um => R=15mm

- Nominal gap: 35um => s=48um => R=10mm

- Maximum gap: 50um => s=63um => R=8mm


The second figure shows somewhat realistic arrangement of the pieces

Attachment 1: sapphire_stand_off_v3.pdf
sapphire_stand_off_v3.pdf
Attachment 2: arrangement-v3.pdf
arrangement-v3.pdf
  12149   Fri Jun 3 14:24:13 2016 SteveUpdateSUSlocal EQ 3.1 m

Local EQ 3.1 mag at Jun 2, 2016 11:06:16 PM UTC, Muscoy CA........no damage

Our STS should seen this shake.

 

Attachment 1: eq3.1mMuscoyCa.png
eq3.1mMuscoyCa.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
  12168   Fri Jun 10 16:19:03 2016 ericqUpdateSUSETMX watch

ETMX has been jumping around again lately. Just now, I zeroed the ETMX alignment offsets in the SUS model, and centered the ETMX oplev spot via slow machine sliders. OSEM damping is on, oplev damping is off. Let's see how it moves around in the next day or so. 

GPS: 1149635923 

UTC: Jun 10 2016 23:18:26

  12171   Mon Jun 13 10:01:58 2016 SteveUpdateSUSETMX jumps

 

Quote:

ETMX has been jumping around again lately. Just now, I zeroed the ETMX alignment offsets in the SUS model, and centered the ETMX oplev spot via slow machine sliders. OSEM damping is on, oplev damping is off. Let's see how it moves around in the next day or so. 

GPS: 1149635923 

UTC: Jun 10 2016 23:18:26

 

Attachment 1: noDamping24hrs.png
noDamping24hrs.png
Attachment 2: ETMXjumps.png
ETMXjumps.png
  12177   Tue Jun 14 15:55:17 2016 ericqUpdateSUSETMX watch

Within two hours, it was already all over the place. 

It has been Decided: we will assemble a suspension with the spare ETM optic with the current-generation standoff for installation ASAP. I.e. no new custom parts. We will continue pursuing the new standoff design, but we need our interferometer back.

  12178   Tue Jun 14 16:53:16 2016 ranaUpdateSUSETMX watch

What about ETMY? and are these really microradians or just some made up cal?

  12187   Thu Jun 16 11:10:17 2016 SteveUpdateSUSspare ETMX optics preparation to be hanged

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 from www.electroenergy.com

 

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-wirestandoff gluing fixture 1 1

Ok for larger RUBY,

unit is not in perfect condtition but usefull

 

         
  First contact   3-15-2013 purchase

Pick up  FC from Gary with purchasing date 7-7-2015

or later

  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 7-7

Attachment 1: SOSsus_Page_1.png
SOSsus_Page_1.png
Attachment 2: SOSsus_Page_2.png
SOSsus_Page_2.png
Attachment 3: ETMXspareTowerFace.jpg
ETMXspareTowerFace.jpg
Attachment 4: ETMXspareTowerBack.jpg
ETMXspareTowerBack.jpg
Attachment 5: magnets-dumbbells.jpg
magnets-dumbbells.jpg
  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
  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
  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.

 

  12227   Wed Jun 29 14:32:22 2016 SteveUpdateSUS how to remove epoxy from optics

 

Hi Steve -

I found the doc I was looking for:

https://dcc.ligo.org/LIGO-E1200821

Specifically, you might find guidance in Section 5 and the pictures at the end of the doc.  This should work for Vacseal as well.

Good luck - it will take some time (hours to day or 2)...
I'll be interested to know how it goes.

GariLynn helped us develop this procedure so you could also ask her to cast an eye over the setup if you are worried.

-Betsy

ps: there is no existing fixture to hold SOS optic while soaking it
 

  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
  12230   Wed Jun 29 16:05:47 2016 ericqUpdateSUSETMX suspension readiness

I've gone through the SOS suspension document (E970037) and some old elogs to get an idea of all the accesories we need for the process of suspending, aside from the tower itself, which Steve has already put together. Gautam and I have laid our eyes upon most of the critical pieces. Some other objects are unknown, and perhaps not strictly neccesary. 

Confirmed to exist:

  • Guide rod gluing fixture
  • 3 axis micrometer + microscope doohicky
  • PZT buzzer (for fine standoff positioning)
  • Winch fixture (the plate maybe doesn't fit perfectly on the top of the SOS tower, but one bolt will probably work)
  • Spare guide rods and ruby standoffs
  • Magnet+dumbell gluing fixture (in case we need to glue a new magnet+dumbell pair)
  • Magnet to optic gluing fixture (including "pickle pickers"/grippers)
  • 0.017" suspension wire
  • HeNe laser + QPD + beam height target (confirmed working on scope)

In addition, I am told that we have a long ribbon cable that can run from the X end to the clean room to enable OSEM damping control while we do the pitch alignment.

Things mentioned in the procedure I have not found:

  • Something called an "SOS set screw tool" (D961412)
    • Not mentioned specifically what this is for
  • Edmund scientific pocket measuring microscope + bushing
    • Seems to be intended for centering OSEM holding plate on the magnet position. I found no mention of this use in 40m elogs. It can likely be done by eye
  • SOS cleaning bracket (D970181)
    • This is likely for the old liquinox cleaning procedure. We'll be using first contact.

Some other tasks and their status:

  • Check cleanroom table levelling:
    • Done via 12" spirit level, looks good
  • Glue removal strategy / fixture
    • Steve is working on this
  • Cut and apply viton tips to earthquake stops
    • Either gautam will do this, or we will use the current suspension's stops
  12231   Thu Jun 30 10:03:16 2016 SteveUpdateSUS how to remove epoxy from optics

Proposed Acetone soak dish for SOS epoxy softening.

It has good acces through 5" top ID. The set up is stable and teflon lined.

Materials: glass jar with SS cover, teflon bricks, 0.008" teflon wrapped "high density Drever bricks" and aluminum

Drever brick: I beleive it is a Tungsten alloy. We used it as vac-bat savor at the coffe can. It has high density, heavy and hard, it was never identified.

I will soak one brick  to see if it has any reaction ability with acetone.

 

NO means that only Glass and Teflon can be used for this fixture in  Acetone. We can not take a chance on the coating!

I guess the small surface area Aluminum dumbbell, guide rod and-or wire standoff, magnet and epoxy does not degrade the acetone such way that it effects our coating.

Not ot mention, that only the very edge of the coating would in this solution.

              

 

Attachment 1: SOSsoakDish.jpg
SOSsoakDish.jpg
Attachment 2: SOSsoakDish_tv.jpg
SOSsoakDish_tv.jpg
  12232   Thu Jun 30 14:31:02 2016 ChemistryUpdateSUSNO

  12241   Tue Jul 5 09:25:31 2016 SteveUpdateSUS how to remove epoxy from optics

Glass soaking dish with teflon guides.

Quote:

Proposed Acetone soak dish for SOS epoxy softening.

It has good acces through 5" top ID. The set up is stable and teflon lined.

Materials: glass jar with SS cover, teflon bricks, 0.008" teflon wrapped "high density Drever bricks" and aluminum

Drever brick: I beleive it is a Tungsten alloy. We used it as vac-bat savor at the coffe can. It has high density, heavy and hard, it was never identified.

I will soak one brick  to see if it has any reaction ability with acetone.

 

NO means that only Glass and Teflon can be used for this fixture in  Acetone. We can not take a chance on the coating!

I guess the small surface area Aluminum dumbbell, guide rod and-or wire standoff, magnet and epoxy does not degrade the acetone such way that it effects our coating.

Not ot mention, that only the very edge of the coating would in this solution.

              

 

 

Attachment 1: SOSsoakingDish.jpg
SOSsoakingDish.jpg
Attachment 2: SOSsoakingD.jpg
SOSsoakingD.jpg
  12264   Thu Jul 7 09:13:54 2016 SteveUpdateSUSSOS gluing fixture

Atm 1, It's right arm is perfect.

Atm 3-4, The left one has bended (dropped) end.

Atm 2, Our ruby wire stanoffs will fit the jig. Ruby OD 1.27 mm vs. old Aluminum OD 1.0 mm. Length ruby 6.4 mm vs Al 4.8 mm

Atm 5, The fixture translation stages are a bit loooose. Careful use of the micrometer is needed to be precise

Betsy agreed that the 40m will keep SOS fixtures.

Attachment 1: SOSgluingFixRarmWend.jpg
SOSgluingFixRarmWend.jpg
Attachment 2: SOSgluingFixRarm.jpg
SOSgluingFixRarm.jpg
Attachment 3: SOSgluingFixLarm45.jpg
SOSgluingFixLarm45.jpg
Attachment 4: SOSgluingFixLarm.jpg
SOSgluingFixLarm.jpg
Attachment 5: SOSgluingFixture.jpg
SOSgluingFixture.jpg
  12315   Wed Jul 20 13:58:55 2016 SteveUpdateSUSSUS damping out of vac chamber

Cheater cable to be used in clean room pitch gluing alingment.

Satelite amp needs to be there.

Atm 2-3, The ETMs  suspension damping cable  are connected at the end racks. All others go to 1X5

Atm 4-5, The other end of this cable in the high cable tray at 1X3 as shown. We'll disconnect the shorty and move the end to ETMX ( or any sus at 1X5 )

 

Attachment 1: ETMXrack.jpg
ETMXrack.jpg
Attachment 2: fromETMX-satBox.jpg
fromETMX-satBox.jpg
Attachment 3: susDampingSatboxCab.jpg
susDampingSatboxCab.jpg
Attachment 4: susDampingSatboxCabl.jpg
susDampingSatboxCabl.jpg
  12316   Wed Jul 20 14:03:01 2016 ericqUpdateSUSEffect of thicker ruby standoffs

The new ETMX ruby guide rods are slightly thicker than the old aluminum ones; specifically 1.27mm vs 1.0mm.

Since we did not change the guide rod location in response to this fact, the vertical position of the suspension point changes, which in turn changes the dynamics of the suspension. Specifically, since the standoff is placed below the guide rod, the suspension point is lowered, which makes the pitch mode softer. I crunched a few numbers and have determined that this effect should not be a problem.

Given the wiki's value of the ETMX pitch resonance frequency of 0.829 Hz, I predict a the new pitch resonance frequency of 0.800 Hz.

(wiki link: https://wiki-40m.ligo.caltech.edu/Suspensions/Mechanical_Resonances)


A useful document about the dynamics of our suspension can be found at T000134

From this document, one will find that the effect of changing the suspension point height over the optic center of mass,`b`, on the pitch resonance frequency (while keeping all other dimensions equal) to be:

\frac{\omega'_\theta}{\omega_\theta} \approx \sqrt{\frac{b'}{b}}

The top of the standoff is fixed by the guide rod, so let's say that b' is given by the position of the center of the Ruby standoff. This is then smaller than the previous b by the differences in the radii of the standoffs:

b' = b - \frac{\oslash_{\textrm{ruby}}-\oslash_{\textrm{Al}}}{2}

The nominal value of b is 0.985mm. Thus, the pitch resonance frequency is changed by factor of 0.965, i.e. 3.5% smaller. Then, taking the wiki value of 0.829 Hz results in 0.800Hz, a 30mHz decrease.

  12334   Mon Jul 25 17:01:54 2016 SteveUpdateSUSETMX suspension - progress

ITMY side  : Magnet od 1.9 mm so wire to magnet gap ~ 0.2-0.3 mm

 

Attachment 1: ITMYside2011.JPG
ITMYside2011.JPG
  12341   Wed Jul 27 11:40:48 2016 steveSummarySUSoplev laser summary updated

 

Quote:

 

Quote:

 

Quote:

 

Quote:

 

                  2005              ALL oplev servos use Coherent DIODE LASERS # 31-0425-000, 670 nm, 1 mW

    Sep. 28, 2006              optical lever noise budget with DC readout in 40m,  LIGO- T060234-00-R, Reinecke & Rana

    May  22, 2007              BS, SRM & PRM  He Ne 1103P takes over from diode

    May  29, 2007              low RIN He Ne JDSU 1103P selected, 5 purchased sn: T8078254, T8078256, T8078257, T8078258 & T8077178 in Sep. 2007

    Nov  30, 2007               Uniphase 1103P divergence measured

    Nov. 30, 2007               ETMX old Uniphase 1103P  from 2002 dies: .............., running time not known......~3-5 years?

    May 19, 2008               ETMY old Uniphase 1103P from 1999 dies;.....................running time not known.....~    ?

    Oct.  2, 2008                ITMX & ITMY are still diodes, meaning others are converted to 1103P earlier

 

                     JDSU 1103P were replaced as follows:

   May 11, 2011                ETMX replaced, life time 1,258 days  or 3.4 years

   May 13, 2014               ETMX , LT 1,098 days or 3 y

   May 22, 2012               ETMY,  LT 1,464 days or  4 y

   Oct.  5, 2011                BS & PRM, LT 4 years,  laser in place at 1,037 days or 2.8 y

   Sep. 13, 2011               ITMY  old 1103P &    SRM    diode laser replaced by 1125P  ..........old He life time is not known, 1125P in place 1,059 days or 2.9 y

   June 26, 2013              ITMX 622 days or 1.7 y    note: we changed because of beam quality.........................laser in place 420 days or 1.2 y

 

  Sep. 27, 2013               purchased 3 JDSU 1103P lasers, sn: P893516, P893518, P893519 ......2 spares ( also 2 spares of 1125P of 5 mW & larger body )

 

      May  13, 2014             ETMX,  .............laser in place 90 d

      May  22, 2012             ETMY, 

     Oct.  7,  2013             ETMY,  LT  503 d  or  1.4 y............bad beam quality ?

     Aug. 8,  2014              ETMY,  .............laser in place   425 days  or  1.2 y

 

      Sept. 5, 2014              new 1103P, sn P893516  installed at SP table for aLIGO oplev use qualification

     

           May 23, 2016             ITMX dead laser sn P845648 replaced after 1062 days [2.9 yrs] by 1103P, sn P859884, with output output  2.6 mW, nicely round beam quality at 15 meters.

               July 27, 2016             2  new 1103P from Edmonds in: P947034 & P947039, manf. date April 2016,

  12342   Wed Jul 27 15:03:02 2016 sisyphusMetaphysicsSUSBroken wire

While tightening the bolts on the ETMX wire clamp, the wire broke. All four face magnets broke off. 

Fortunately, no pieces were lost.

  12343   Wed Jul 27 16:56:47 2016 ranaMetaphysicsSUSBroken wire

For the rest of this vent, at least, we need to start using the EQ stops more frequently. Whenever the suspension is being worked on clamp the optic. When you need it to be free back off the stops, but only by a few hundred microns - never more than a millimeter.

Best to take our time and use the stops often. With all the magnets being broken off, its not clear now how many partially cracked glue joints we have on dumbells which didn't completely fall off.

  12346   Thu Jul 28 08:42:36 2016 SteveUpdateSUS wire clamp

The clamp is in the machine for milling off the grooves. It's condition is normal. The edges needs some 800 sand paper so it is not sharp anywhere.

How did those nicks get on the edge? Fortunatelly they did not aligned with the wire.

 

Attachment 1: e12342.jpg
e12342.jpg
  12353   Fri Jul 29 03:59:55 2016 ericqUpdateSUSIn air OSEM diagonalization check

The question arose whether we can get good enough data to diagonize our OSEM sensing matrices in air. 

I just took a look at the BS spectra over the last six hours (~10PM-4AM), and the SNR looks good. The BS diagonalization itself doesn't seem so great; the POS is hugely coupled into pitch and yaw, and the angular motions are themselves coupled to each other at around 10%. 

NB: use a flat-top window when you really care about peak heights that don't fall exactly on an FFT bin. 

I would've liked to check this for the PRM and SRM too, but one of the PRM sensors continues to be dark, and I just noticed that all of the SRM OSEM signals are dark. ughhhh

Attachment 1: BS_OSEM_diag.pdf
BS_OSEM_diag.pdf
  12355   Fri Jul 29 15:17:23 2016 SteveUpdateSUSwire and clamping test

Unbaked steel music wire from  "Ca Fine Wire Co" from 24" od spool, od 0.0017" used. Identical to the one that broke.

The set up as shown with silver plated screws-washers on clamp. The unused clamp edges were sanded on P800 paper at 45 degrees just not to be very sharp.

Use your finger to feel the sharpness of  edge and sand till it gets a little bit not so sharp. The drawing note is "sharp edges" on wire clamp for low loss, high Q in mind.

The wire broke at the midle with single load 295 grms

The wire hold on overnight at single load 242 grms  Vezo torque wrench is not accurate!  This test was performed ~ 1.5Nm  DO NOT USE THIS NUMBER! (added at 8-10-2016)

This gives us a factor of 2 safety  with loop suspended of 250 grms small optic.

 

 

Attachment 1: 43micr242grs.jpg
43micr242grs.jpg
  12357   Fri Jul 29 20:12:54 2016 gautamUpdateSUSthird time - no luck

[lydia, gautam]

Summary: Third unsuccessful attempt at getting ETMX suspended. I think we should dial the torque wrench back down to 1.0 N m from 1.5 N m for tightening the primary clamp at the top of the SOS tower. No damage to magnets, standoff successfully retrieved (it is sitting in the steel bowl)

Details:

  • We burned through two sets of wires today.
  • First, the assembly Eric and I had put together last night failed when Eric tightened the wire clamp (no torque wrench was used I think?)
  • This afternoon, Lydia and I re-assembled the suspension once again. Standoff was successfully inserted, coarse pitch balancing was achieved relatively easily - we think that the coarse pitch balance can be achieved if the end of the wire standoff closer to the groove is ~0.5mm ahead (i.e. towards HR side) of the guide rod.
  • Checked leveling of scribe lines, gave an extra 0.25 turns on the winches in anticipation of the wire sagging
  • Inserted OSEMs just short of magnets, verified that they were approximately centered, if anything, slightly above center, again in anticipation of the wire sagging. 
  • After taking pictures, we went ahead and attempted to clamp the wire (ALL EARTHQUAKE STOPS WERE ENGAGED)
  • Eric commented that the clamp piece did not slide in smoothly on the dowels (indeed it does not come off very easily either, I have just left it on for now). I don't remeber it being so difficult prior to us sending it into the maching shop to get rid of the grooves made by the suspension wire the first time around. But with the torque wrench, the piece moved in relatively easily (we had sanded down rough edges prior to putting this piece onto the suspension earlier in the afternoon.
  • I could feel that the torque wrench coming up on its limit. But the wire snapped before the torque wrench clicked. As far as I am aware, there were no rough edges on the piece, but perhaps we missed a spot?
  • I took the opportunity to discharge the optic using ionized nitrogen at 40psi. After about 2-3 minutes of a steady stream, I verified that a piece of the suspension wire no longer gets attracted to the barrel, as was the case earlier today.

Unfortunately I don't know of a more deterministic way of deciding on a "safe" torque with which to tighten the bolts except by trial and error. It is also possible that the clamping piece is damaged in some way and is responsible for these breakages, but short of getting the edges chamfered, I am not sure what will help in this regard.


Unrelated to this work: earlier today before the first wire failure, while I was optimistic about doing fine pitch balancing and gluing the standoff, I set up an optical lever arm ~3m in length, with the beam from the HeNe on the clean bench at 5.5 in above the table, and parallel to it (verified using Iris close to the HeNe and at the end of the lever arm). I also set up the PZT buzzer - it needs a function generator as well for our application, so I brought one into the cleanroom from the lab, isopropanol wiped it. The procedure says apply 5Vrms triangular wave at 1000Hz, but our SR function generators can't put out such a large signal, the most they could manage was ~2Vrms (we have to be careful about applying an offset as well so as to not send any negative voltages to the PZT voltage unit's "External input". All the pieces we need for the fine pitch balancing should be in the cleanroom now.

  12359   Mon Aug 1 14:09:20 2016 SteveUpdateSUSthird time - no luck

Gautam and Steve,

The clamp's left side was jammed onto the left guide pin. It was installed slit facing left. Gautam had to use force to remove it. The clamp should move freely seating on the guide rods till torque aplied. Do not move on with the hanging of optic with a jammed clamp. Fix it.

Never use force as you are hanging - aligning optic. The clamp is in the shop for resurfacing and slit opening.

 

  12362   Wed Aug 3 00:15:39 2016 gautamUpdateSUSETMX suspended

[lydia, steve, ericq, gautam]

Summary:

  • ETMX is now suspended by wire clamps (winches have been removed) yes
  • Wire clamp was machined by shop, D groove widened to spec, old wire grooves removed from face
  • We also sanded the part of the suspension tower in contact with the primary wire clamp, as there were a couple of craters there which looked dangerous (pictures to follow)
  • Height was adjusted by centering magnets on OSEMs. We then winched an extra half turn in anticipation of wire sag
  • I then proceeded to tighten, first, the primary wire standoff (I reduced the torque on the torque wrench to ~1.25Nm), and then the secondary wire clamps.
  • Checked that the ruby standoff is sitting on the optic barrel and not on glue 
  • Later in the evening, I inserted OSEMs, centered magnets, and checked that the damping scheme set up last week works (I'm leaving the damping on, bottom EQ stops are ~0.5mm from the optic)
  • Checked the pitch balancing - initially, we were ~60mrad off. By using the tweezers to gently adjust the position of the ruby standoff (after clamping the optic, turning the damping off), I was able to improve the situation a little bit - now we are ~20 mrad off. I am not attempting to do the fine pitch balancing tonight, but all parts of the PZT buzzer set up are ready to go in the cleanroom.
  • Unfortunately, in the process of doing the pitch balancing, the position of the magnets relative to the OSEM coils have moved. Now the UR magnet looks a little high relative to the coil, but perhaps after any sag has set in, we should be alright. Else, we can probably get away by inserting one of the little metal shim pieces, the adjustment required is small.
  • Lydia will upload some photos soon. 
  • We actually went through another failed attempt today - this time, the problem was that the winches were not sufficiently secure at the top, such that when the range of the winch was nearing its end, the whole assembly twisted and took the wire along with it. Perhaps this would not have happened if we had a winch adaptor plate handy...
  • Plan for tomorrow:
    • ​Fine pitch balancing using PZT buzzer
    • Clean ETMY epoxy residue from knocked off magnet
    • Glue wire standoff
    • Glue ETMY magnet
  12363   Wed Aug 3 09:26:54 2016 LydiaUpdateSUSETMX suspended: photos

Here are the photos we took showing the magnet positions in the OSEMs, and others showing the positions of the wire and unglued standoff. These were taken before the pitch balancing adjustment Gautam described, which apparently cause UR to be a little too high. Thoe OSEMs were all inserted only until the ends of the magnets were almost inside, to lower the risk of knocking any magnets off.

 At the time of these pictures, all magnets except LL were intentionally positioned slightly above the center of the OSEM in anticipation of wire sag. The LL magnet was approximately centered in the OSEM. It was not possible to get both LL and UL the same height relative to their respective OSEMs, possibly due to a spacing error when they were glued to the optic. 

Attachment 1: Position of wire along bottom of the optic. Looks adequately centered and not kinked. 

Attachment 2: Photo showing good contact between the sandoff and the barrel of the optic. The standoff does not appear to be resting on glue from the guiderod. 

Attachment 3: Shows position of standoff and wire after rough pitch banacing. Wire is visibly resting in the groove.

Attachment 4: SD magnet location photographed through OSEM.

Attachment 5: LL magnet location photographed through OSEM.

Attachment 6: LR magnet location photographed through OSEM.

Attachment 7: UL magnet location photographed through OSEM.

Attachment 8: UR magnet location photographed through OSEM.

 

Attachment 1: wire_bottom.JPG
wire_bottom.JPG
Attachment 2: standoff_contact.JPG
standoff_contact.JPG
Attachment 3: wire_in_groove.JPG
wire_in_groove.JPG
Attachment 4: SD.JPG
SD.JPG
Attachment 5: LL.JPG
LL.JPG
Attachment 6: LR.JPG
LR.JPG
Attachment 7: UL.JPG
UL.JPG
Attachment 8: UR.JPG
UR.JPG
  12367   Wed Aug 3 15:36:57 2016 SteveUpdateSUSNi plated magnets & epoxy ordered

Ni plated SmCo magnets with specification of LIGO-C1103521-v2 for SOS ordered from Electron Energy Corp 

100 pieces of Ni- Platted magnets are in 9-27-2016 They are stored at clean cabinet S15

EP30-2 epoxy  1/2 pt kit 250 ml of part A and 25 ml of part B should be here in 7 days. These can packed epoxy is much more economical than the double barrel cartridges.

Spare SOS wire clamps will be out of the machine shop next week.

  12370   Thu Aug 4 03:14:39 2016 gautamUpdateSUSETMX suspended
Quote:

[lydia, steve, ericq, gautam]

Summary:

  • ETMX is now suspended by wire clamps (winches have been removed) yes
  • Unfortunately, in the process of doing the pitch balancing, the position of the magnets relative to the OSEM coils have moved. Now the UR magnet looks a little high relative to the coil, but perhaps after any sag has set in, we should be alright. Else, we can probably get away by inserting one of the little metal shim pieces, the adjustment required is small

[lydia, ericq, gautam]

  • Turns out setting the height of the optic with the OSEMs isn't quite reliable. We were indeed too high, for all the OSEMs
  • Related to the above - we observed no sag (which is one of the reasons we winched a little bit extra in the first place)
  • Eric and I re-did the suspension in the afternoon. We found no wire grooves in the primary (or secondary) clamps, so we just reused them (is this a red flag? should we be using more torque?)
  • This time we set the height using the traveling microscope - double checked the height to which the microscope was levelled = 5.5"
  • Having checked the height of both scribe lines, we proceeded to clamp the suspension, with ~1.35Nm of torque (since 1.25Nm seemed a little low, no wire grooves were made in the clamps) - clamping was successful
  • In the evening, Lydia and I attempted to do the fine pitch balancing
  • Both left side magnets (as viewed from the AR side) are low (within 0.5mm of the teflon). Right side magnets are pretty well centered. But left side ones seemed usable so we went ahead and tried to turn the damping on.
  • Damping worked reasonably well
  • Tried to do fine pitch balancing with PZT buzzer. Reduced voltage from Fn generator to 0.4Vrms (down from 1.7Vrms) but had limited success. 
  • I was able to do much better with just the teflon tipped tweezers. So gave up on the PZT buzzer
  • After ~3hours of a random walk between two pretty-close-to-ideal positions, we have now realized a fine pitch balancing of ~1mrad (~3mm off the ideal height of 5.5" over a lever arm of ~1.5m, but the mirror tilt is half of this angle)
  • Actually, I was able to do much better - at one point, we even had the reflected beam dead center on the iris 1.5m away. But adjusting the OSEM positions even a little bit (say from oscillating around 40% to 50% of the maximum value) has a BIG effect on the pitch balance (it caused a misalignment of 4mrad)
  • I think gluing the standoff without destroying the fine pitch balancing is going to be very challenging, judging by how gently I had to touch the standoff to destroy the fine pitch balance completely. Perhaps we want to consider using some 3 axis stage to bring the needle with glue in and perturb the standoff as little as possible

    Lydia also briefly played around with the IR camera to inspect the OSEMs. A more thorough investigation will be done once the cage is in for air baking. From our initial survey, we feel that the beams are pretty well aligned along the straight line between PD and LED - we estimate the upper bound on any misalignment to be ~10 degrees.

 

  12377   Fri Aug 5 02:17:10 2016 gautamUpdateSUSETMX Ruby Wire Standoff Ready for Gluing

Part 1: Rotation of optic

  • As reported in my elog yesterday, both the left magnets (UL and LL) seemed too low relative to the OSEM coils
  • Eric and I checked the height of the scribe lines using the microscope and found that the scribe lines were low on the left side and high on the right side (as viewed from the AR side) by approximately the same amount, confirming our suspicion that the optic was rotated. The position of the scribe line on the bottom of the optic relative to the bottom-rear face EQ stop also suggested the same
  • Eric brought in the bottom EQ stops, and once the wire was slightly unloaded, rotated the optic by the required amount by hand 
  • This process took two tries, but we were successful
  • Re-checked heights of scribe lines using microscope, and once we were satisfied, re-did the coarse pitch balancing

Part 2: Replacement of holder for top pair of OSEMs

  • Eric and I had difficulty removing the UR OSEM-holding screw
  • This is the non-silver-coated new variety of screw
  • It got to a point where I could neither move the screw in or out, even with the help of a pair of pliers
  • I decided to swap out the piece of the suspension tower holding the top two OSEMs (UR and UL) with the same piece from the old ETMX tower that is currently residing on the flow bench at the south end (along with the accompanying piece that overhangs the optic and holds the front-face and top earthquake stops
  • I cleaned the piece 3-4 times with acetone, and then a couple of times with isopropanol. I adjudged this to be sufficient as we are going to air bake the tower anyways prior to installation in the vacuum chamber
  • I then swapped the pieces:
    • First I brought in the bottom pairs of EQ stops
    • Next, I secured the optic using the three lower face EQ stops
    • Then, I removed the EQ stop screws from the overhanging piece, after which I removed the overhanging piece itself
    • After removing the top-back EQ stop, I removed the OSEM-holding piece from the suspension tower
    • Did the above steps in reverse, installing the new piece
  • All went smoothly. This piece does not have a serial number unfortunately
  • After this, I re-inserted the OSEMs, and judged the magnet-coil alignment to be satisfactory to proceed further
  • We decided to use the old variety of silver plated OSEM holding screws for the top two OSEMs (by choice) and the side OSEM (the new variety is too short anyways). During the course of my work tonight, I found this worked way better. The bottom pair of OSEMs remain held by the new variety of unplated screws. We may want to review whether we really want to use this new type of screws (I believe the idea is to make it easier to tighten and loosen the screws)

Part 3: Fine pitch balancing

  • As per the SOS assembly procedure, I turned off the HEPA filters at the clean bench for this part of the work
  • Checked that the HeNe beam incident on the optic was level with the tabletop, beam height set to 5.5"
  • Proceeded to do the fine pitch balancing the same way as described in yesterday's elog (i.e. no PZT buzzer, just fine touches by hand)
  • I was able to converge fairly quickly to a good point in configuration space
  • After re-centering the OSEM coils such that the PD output was ~50% of its maximum value (see Attachment #1), I found over a lever arm length of 56" (=1.42m) a beam height deviation from 5.5" by <2mm. This corresponds to 0.7mrad pitching forwards towards the HR side
  • The suspension assembly procedure tells us to aim for 0.5mrad, but I think this is close enough for standoff gluing, as this misalignment is extremely sensitive to the OSEM coil positions (although I would say, from Attachment #1, that they are actually pretty well centered)
  • The only thing that concerns me is that the LL magnet is still a little low relative to the coil. This can be fixed by shimming if necessary...

Attachment #1: Striptool trace showing OSEMs are pretty well centered (towards the end, I turned on the HEPA filters again, which explains the shift of the traces). The y-axis is normalized such that the maximum displayed corresponds to the fully open PD output of the coils

Attachment #2: Fine pitch balancing optical lever setup

Attachment #3: Tower assembly

Attachment #4: SIDE OSEM close-up

Attachment #5: UR OSEM close-up

Attachment #6: UL OSEM close-up

Attachment #7: LL OSEM close-up (this is the concerning one)

Attachment #8: LR OSEM close-up


We should also check the following (I forgot and don't want to wear my clean jumpsuit again now to take more photos):

  1. Wire is still in groove
  2. Standoff is sitting on the optic barrel and not on epoxy residue of the guiderod
Attachment 1: OSEMs.PDF
OSEMs.PDF
Attachment 2: IMG_2932.JPG
IMG_2932.JPG
Attachment 3: IMG_2934.JPG
IMG_2934.JPG
Attachment 4: IMG_2935.JPG
IMG_2935.JPG
Attachment 5: IMG_2936.JPG
IMG_2936.JPG
Attachment 6: IMG_2937.JPG
IMG_2937.JPG
Attachment 7: IMG_2938.JPG
IMG_2938.JPG
Attachment 8: IMG_2939.JPG
IMG_2939.JPG
  12378   Fri Aug 5 04:43:09 2016 KojiUpdateSUSETMX Ruby Wire Standoff Ready for Gluing

If only the LL magnet looks too low, doesn't this mean that the OSEMs are not arranged in a square shape?
If so, you can fix this misalignment by moving the OSEM holding plate rather than OSEM shimming, can't you?

  12379   Fri Aug 5 09:38:12 2016 SteveUpdateSUSSOS sus wire ordered

0.0017" OD., 500ft steel music wire ordered. Pictures of the existing roll are below. It will be on 8" OD. spool too.

 

Attachment 1: 0.0017.jpg
0.0017.jpg
Attachment 2: 0.0017spec.jpg
0.0017spec.jpg
ELOG V3.1.3-