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ID Date Author Type Categorydown Subject
  7361   Fri Sep 7 13:01:53 2012 ManasaConfiguration40m UpgradingBaffle problem

Quote:

Quote:

The required diameter for the baffle if it sits on the cage at 1.77" from the test masses: the current baffle (dia. 40mm) centered along the beamline, will allow ~8.6mm visibility from the center of the test mass (in case of ETMY).

*assuming the pick off mirror is placed at the edge of the tunnel

Estimations of the visibility region (r1 on the test mass) with baffle (aperture size 40mm).

The baffle is installed on the cage at 1.125" from the test mass (distance changed from the previous elog after a double check).

The 40mm aperture is in no way going to help get clear view of the ITMs; 

Required baffle diameter to have a visibility region r1 = 3 times the beam diameter

Picture1.png

  7449   Thu Sep 27 19:03:06 2012 ManasaUpdate40m UpgradingNew ETMX layout - Version 1.0

 I am working towards redesigning the endtables. I've attached the first version of the layout. As per Steve's comment I've tried to leave a 2" empty space on all sides of the table. It still has to be updated with the whole 40m layout to be more precise about the pickoff and the ingoing beam directions.

Attachment 1: ETMX_OldNew.png
ETMX_OldNew.png
  7450   Thu Sep 27 20:05:57 2012 KojiUpdate40m UpgradingNew ETMX layout - Version 1.0

1. I wonder how the mode profiling/matching was considered in the new layout.

I can see the distances between the components and lenses are largely different from the old ones.

This is OK if you plan to go through a new mode matching solution with new lenses.
But it takes
 a certain amount of time.

Note that we don't care the distance after the last lens as the Rayleigh range there is supposed
to be long enough to allow this kind of change.

2. The huge frustration of the green alignment in the old setup was caused by the 3D beam steering
at the last two 2" mirrors. i.e. the beam elevation on the table does not match with the beam elevation of the cavity.
In order to avoid this, I suggest you to use three 45 deg 2" mirrors instead of two. In fact these mirrors are supposed to be used at 45deg incidence!

3. The incident green beam and the transmitted IR beam should share a same path as they
 share a same cavity mode.
This means that you should use a harmonic separator for the transmitted light pick-off.

4. Use the harmonic separator for the fiber path too. Get the mirror spec from Jamie.

5. Since the optical window on the chamber has a wedge angle, the beam paths are not straightforward.
The cavity beams can't be moved as they are constrained by the arm cavity.
Probably there is almost no freedom to move even for the oplev beams.
It would be safe just to follow the old positions and angles on the window.
Make sure the beam on the drawing is realistic. The angles of the oplev beams in the old setup look strange.

Is there a possibility to replace the optical window so that it has an AR for 532 and 1064 at least???

6. I wonder if the rejected beam by the Farady have a realistic angle or not. Check it with the old setup.
It is definitely better to have a steering mirrror and a lens before the refl PD.

7. The IR QPD and trans PD are intended to be used for the low and high power detection.
I forgot which is which. So check the range of them and think about the power distribution.

8. We should have separated CCDs for IR Trans and Green Refl.
We had a terrible ghost green beam on the IR trans CCD.
Thus, think about the amount of ghost reflection and consider filtering if necessary.

  7451   Fri Sep 28 07:49:30 2012 SteveUpdate40m UpgradingNew ETMX layout - Version 1.0

  Where is IP-ANG ? It is good practice to use two mirrors at launching and detecting the beam, so you can walk it - precisely adjust it.

The window can be replaced at  ~$1,500 ea. 10 weeks as optical quality BK7 with dual AR

  7704   Tue Nov 13 11:30:54 2012 ManasaConfiguration40m UpgradingEndtable upgrade for auxiliary green laser

I'm set on the mission to get the new bigger endtables setup for the auxiliary green laser; now that the tables are already here.

I want to have everything documented in this same thread for future reference. It has been a pain trying to filter relevant elogs. I'll be working on the layout redesign one at a time....starting with the ETMX end.

This is the simplest cartoon layout of  ETMX endtable (not the actual table layout):

ETMX_sch.png

I have been searching through the elogs for the beam parameters measured earlier. I'm assuming they would not have changed much and will make calculations based on them.

However, we will have to change a few not-so-good mounts and include/exclude some optics.

 

P.S. HR (steer) are necessary steering mirrors and HR are just folding mirrors for the drawing.

 

 

 

  7705   Tue Nov 13 16:18:51 2012 ManasaConfiguration40m UpgradingEndtable upgrade for auxiliary green laser : Circularize the 1W NPRO beam profile

With reference to measurements made earlier: elog

Beam parameters for Innolight 1W NPRO are:

wx0 = 160 um 

wy0 = 181.1 um

z0x = -9.17 cm

z0y = -10.19 cm

The beam is clearly elliptical.  We will introduce an additional pair of cylindrical lenses to circularize the beam before it enters the faraday.

I made calculations for the beam divergence ratio and checked with thor labs catalogue of cylindrical lenses to find pairs that will match the ratio. 

I propose to use lenses with focal lengths f1 = 22.2 mm and f2 = 25 mm. The beam diameter after the lenses will be dx = 164.05 um and dy = 163.19 um.

  7706   Tue Nov 13 20:13:07 2012 KojiConfiguration40m UpgradingEndtable upgrade for auxiliary green laser : Circularize the 1W NPRO beam profile

These fs are too short.

Quote:

I propose to use lenses with focal lengths f1 = 22.2 mm and f2 = 25 mm. The beam diameter after the lenses will be dx = 164.05 um and dy = 163.19 um.

 

  7726   Mon Nov 19 20:03:53 2012 ManasaConfiguration40m UpgradingEndtable upgrade for auxiliary green laser : ETMX layout on new table

I have attached the possible layout of the optics on the new ETMX endtable. More optics have been added when compared to the early cartoon layout considering that we need additional steering mirrors for reasons like: the table height in and out-of vac are different and several mounts have restricted movement in certain degrees of freedom. 

As you can see, there is enough room for filters and other last time additions that may arise.

I will proceed with calculations based on the distances from the CAD drawing and the spec of the optics if there are no comments or suggestions about the layout.

 

 

Attachment 1: ETMX_endtable_New_Model.pdf
ETMX_endtable_New_Model.pdf
  7727   Mon Nov 19 20:17:53 2012 JenneConfiguration40m UpgradingEndtable upgrade for auxiliary green laser : ETMX layout on new table

 

For convenience, I would include a steering mirror in front of the TRX PD.  Also, don't we usually have lenses in the oplev paths?  Also, also, do we need lenses in front of the green refl and TRX PDs?  Do you have a place in mind for the shutter?  Is there a way to compactify the layout a little bit, so that even if the lenses are different for each table, the general layout for both ETMX and ETMY is the same (with an empty space on ETMX where IPANG belongs on ETMY)?  I'm sure it is, since you've talked to Steve about this, but just to check: is the green refl PD far enough away from the edge of the table to accommodate the fancy new box?

  7728   Mon Nov 19 22:42:14 2012 KojiConfiguration40m UpgradingEndtable upgrade for auxiliary green laser : ETMX layout on new table
  • I don't like the idea to place the cylindrical lenses right in front of the laser.
    This design requires the CLs to be tilted to avoid direct reflections going into the laser.
    It is also required that they are made of UV fused silica to avoid thermal lensing.

     
  • Instead, move the CLs after the farday while we keep L1, HWP, QWP after the laser.
    L1 should be UV fused silica lens. I should be placed with slight tilt.
    It is preferrable to place CLs after the faraday at somewhere the beam is not too small.
     
  • The HWP before the SHG can be moved to downstream of the steering mirrors as they can change the poralization.
    (Probably I am too paranoic.)
     
  • Why don't you use the harmonic separator right after the SHG crystal in stead of relying on an arbitrary transmission of the 532nm mirrors?
     
  • I am not confident about such a "nice" separation angle of the returning beam from the green faraday.
    Confirm the separation angle on the actual setup.

    The beams split in the polarizer rather than in the air like in your diagram.
    Then because of this small angle separation, the pick-off mirror may have a bit more critical distance than you indicated.
    (I could be wrong.)
  • I don't think the green faraday is IO-5-532-HP. It should be IO-?-532-LP.
    Rotate the tilt aligner 180deg so that we can easily access to the adjusting screws
     
  • The green PDA36A path needs more length and probably a focusing lens too.
     
  • After the PLCX lens, the beam is big (w=3mm) everywhere. Don't you want to use 2" mirrors and mounts?
     
  • We eventually will install steering PZTs for the green.
    On which mirrors do you want to install the PZTs?
    Do you have enough spare space for them?
     
  • The mount indicated "HS" is one of the trickiest mounts on the table as the big beam goes through the mirror.
    Probably you want to use 2" suprema mount with correct chirality.
     
  • How is the power budget of the IR trans path? Which is the low power PD and which is the high power PD?
    What's the transimpedance of them? Where is the crossover?
    How much power does go into the CCD? Is it a reasonable amount?

     
  • The IR transmon beam is even larger than the green beam (w=5mm)
    You definitely need a lens to shrink the beam. But we don't want to have the QPD and the CDD at the focus.
     
  • As Jenne pointed out, having a steering mirror for the IR PDA36A is a good idea.
    But do you really want to use the Si PD for the IR tmonitor?
  • I feel I don't want to have the pair of steering mirrors in the oplev incident path. One is enough.
    We should be able to accommodate optional mode-matching lenses in the incident path.
    We definitely don't want to have any lens in the returning path of the oplev.
  7813   Wed Dec 12 11:04:45 2012 ManasaConfiguration40m UpgradingEndtable upgrade for auxiliary green laser : ETMX layout on new table

I have updated the layout to fix all the issues brought up. The last couple of 2" green steering mirrors will hold the PZTs for input steering. I will update with the list of optical components that we will be ordering for this layout. The ETMY endtable layout will be similar to this one, except that we will have IPANG setup at the empty space in the right top corner.

ETMX_endtable_New_Model.png

  7815   Wed Dec 12 14:59:49 2012 ManasaConfiguration40m UpgradingNew tip-tilts layout in BSC

I have updated the BSC layout to include the new tip-tilts. The bigger footprints of the tiptilts are on in the way of the existing PRM oplev path. So I have recalculated new PRM oplev paths. The proposed layout requires a new oplev mirror to be included.

 

bs.png

  7889   Thu Jan 10 12:41:06 2013 ManasaConfiguration40m UpgradingEndtable upgrade for auxiliary green laser : wiki page

 

I have created a wiki page linked here with all details about the endtable upgrade.

The page has links to the new drawing for doubler post to hold the tilt-aligner that holds it. The Faradays will also be mounted similarly on tilt aligners placed on these posts. The bulk mounts will be made of aluminium similar to the colorful cylindrical mounts (images of which can be seen in the archived layouts on the wiki) that hold the He-Ne lasers and few faradays now.

  8228   Tue Mar 5 00:24:52 2013 ManasaConfiguration40m UpgradingEndtable upgrade for auxiliary green laser : customized mount

 Drawing of customized mount for endtable doubler crystal (PV40+PVP2+NP9071) modified and updated on the endtable upgrade wiki page.

  8310   Tue Mar 19 14:21:57 2013 ManasaUpdate40m UpgradingEndtable upgrade : INVENTORY

THE INVENTORY FOR ETMY ENDTABLE.

We definitely need the polaris mirror mounts and cylindrical lenses. As for the rest, we can still go ahead and do the swapping without them.

 

Attachment 1: Endtable_inventory.pdf
Endtable_inventory.pdf
  8312   Tue Mar 19 19:19:50 2013 JenneUpdate40m UpgradingEndtable upgrade : INVENTORY

Does "Ready (in stock)" for the base plates mean in stock at the company, or in hand and already here in the lab?

For the 2" mirror mounts, are we planning on making a decision soon, or a long time in the future....i.e. is this something that should go in the temporary solution column?

For the mode matching and collimating lenses, do we actually have the ones you want in our lens kits?  A lot of those kits are half empty.

  8315   Wed Mar 20 14:00:21 2013 SteveUpdate40m UpgradingEndtable upgrade

As discussed at the 40m meeting: Koji, Manasa and Steve

We are planning to remove the whole 4'x2' optical table ETMY-ISCT with optics as it is tomorrow morning.
This way I can start placing the new 4'x3' table and acrylic enclosure in place.

  8318   Wed Mar 20 15:51:54 2013 ManasaUpdate40m UpgradingEndtable upgrade

Quote:

As discussed at the 40m meeting: Koji, Manasa and Steve

We are planning to remove the whole 4'x2' optical table ETMY-ISCT with optics as it is tomorrow morning.
This way I can start placing the new 4'x3' table and acrylic enclosure in place.

I will be removing all cables on the ETMY endtable and labeling them today before we remove the table tomorrow morning. If there is anything else that should be done before the swapping which we might have not considered, elog it and we'll have it all done.

Also,I've attached the updated inventory.

Attachment 1: Endtable_inventory.pdf
Endtable_inventory.pdf
  8320   Thu Mar 21 08:11:53 2013 SteveUpdate40m UpgradingETMY table swap

Quote:

Quote:

As discussed at the 40m meeting: Koji, Manasa and Steve

We are planning to remove the whole 4'x2' optical table ETMY-ISCT with optics as it is tomorrow morning.
This way I can start placing the new 4'x3' table and acrylic enclosure in place.

I will be removing all cables on the ETMY endtable and labeling them today before we remove the table tomorrow morning. If there is anything else that should be done before the swapping which we might have not considered, elog it and we'll have it all done.

Also,I've attached the updated inventory.

 The cables are Not disconnected. I have people coming to do the lifting at 9:45am  Email is not working. This will cause a delay. I need conformation that we still moving on with the swap

  8321   Thu Mar 21 08:46:46 2013 ManasaUpdate40m UpgradingETMY table swap

Yes! We are swapping.

I'll be there very soon!

  8330   Thu Mar 21 17:06:34 2013 SteveUpdate40m UpgradingETMY table is out

Quote:

Yes! We are swapping.

I'll be there very soon!

 The ETMY optical table 4' x 2' with all optical components was placed on two carts and rolled out of the end.  The 4' x 3' x 4" TMC 78-235-02R breadboard was placed into position and marked for anchoring bolt locations.

It will be drilled, tapped, shimmed, leveled and bolted it into final position tomorrow morning.  I'm planning to bring  the acrylic enclosure to the east end tomorrow afternoon.

Attachment 1: ETMYtableSupport.jpg
ETMYtableSupport.jpg
  8340   Mon Mar 25 18:07:31 2013 SteveUpdate40m UpgradingETMY table is out

Quote:

Quote:

Yes! We are swapping.

I'll be there very soon!

 The ETMY optical table 4' x 2' with all optical components was placed on two carts and rolled out of the end.  The 4' x 3' x 4" TMC 78-235-02R breadboard was placed into position and marked for anchoring bolt locations.

It will be drilled, tapped, shimmed, leveled and bolted it into final position tomorrow morning.  I'm planning to bring  the acrylic enclosure to the east end tomorrow afternoon.

 The new table is tapped and leveled, but not ready for final anchoring. The existing 8 mm shims on the top of the support legs will be moved to the bottom of the legs, where more torque is available on the 1/2" bolts

The coated tin film sheets are being installed at the shop. The table and the enclosure will be ready on Friday.

Attachment 1: shimmingEE.jpg
shimmingEE.jpg
  8341   Mon Mar 25 18:42:38 2013 ManasaUpdate40m UpgradingEndtable upgrade for auxiliary green laser : Timeline

 Endtable upgrade - timeline and progress chart. End table upgrade wiki page updated.

 

Attachment 1: Endtable_progress.pdf
Endtable_progress.pdf
  8355   Tue Mar 26 16:10:31 2013 JamieUpdate40m UpgradingETMY table leveling

Steve's suggestion for how to level the end table using "swivel leveling mounts":

end-tabel-leveling.png

 

  8356   Tue Mar 26 16:36:24 2013 SteveUpdate40m Upgrading table leveling mounts go here

Quote:

Steve's suggestion for how to level the end table using "swivel leveling mounts":

end-tabel-leveling.png

 

1, level table with 4 swivels, lock nuts  3/16 -vertical alignment    2, lock this position with 4 x 1/4-20 (these are in place already) to hold table in horizontal direction

   Adjustable mount is here to compensate for bad tilting  floor <http://www.mcmaster.com/#6111K52>  

      See grouting plans of the past   http://nodus.ligo.caltech.edu:8080/40m/7248

Attachment 1: optabSTAND.PDF
optabSTAND.PDF
Attachment 2: swivvelMountEE.jpg
swivvelMountEE.jpg
  8371   Fri Mar 29 00:27:06 2013 ManasaUpdate40m UpgradingEndtable upgrade for auxiliary green laser : Assembly

I am currently putting together all components so that they are ready to go on the table once leveling and installation of shield box is done. All dirty optics were drag wiped. These are stored in the cupboard along the Y arm.
I could not find the fiber coupling mount on the old endtable. Also the harmonic separator that reflects the trans beam to PDs and camera is labelled Y1-1064 (??) and I don't know what's the deal with this.
I am nearly 70% done with assembling…so the ex-endtable is almost empty.

Yet to do:
1. Mount 2" optics
2. Hunt, gather and mount appropriate lenses

Points I did not notice earlier:
We need some good 2" lens mounts and also order 2" lenses for IPANG and trans beam.

 

IMG_0433.JPGIMG_0434.JPG

  8372   Fri Mar 29 16:30:27 2013 SteveUpdate40m Upgrading table leveling mounts go here

Quote:

Quote:

Steve's suggestion for how to level the end table using "swivel leveling mounts":

end-tabel-leveling.png

 

1, level table with 4 swivels, lock nuts  3/16 -vertical alignment    2, lock this position with 4 x 1/4-20 (these are in place already) to hold table in horizontal direction

   Adjustable mount is here to compensate for bad tilting  floor <http://www.mcmaster.com/#6111K52>  

      See grouting plans of the past   http://nodus.ligo.caltech.edu:8080/40m/7248

 

  8373   Fri Mar 29 16:35:54 2013 SteveUpdate40m UpgradingEndtable upgrade

 

 My full effort to get the optical table enclosure ready for the lab has failed today.

What I did: cut IR thermashield sheets to size for sides and top and sandwitched them beetween 1" and 1/4" acrylic.

                   The carpenter shop recut the bottom o -ring groove to 0.250" wide and 0.150" deep.

                   O-ring was cut and installed. So this was ready to go lab.

                  NO, I realized that the liner yellow acrylic was not cut correctly. It was larger than 1" wall.

                 The shop is cutting them down to fit and I have to resize IR shields

  8392   Tue Apr 2 17:23:23 2013 SteveUpdate40m Upgradingnew ETMY optical table & enclosure in place

 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.

 

Attachment 1: EEopt1d.jpg
EEopt1d.jpg
  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

 

  8417   Fri Apr 5 01:18:34 2013 ManasaUpdate40m UpgradingNot a fan of the new plastic box yet

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

 

While I did think that the plastic boxes were cool; I am not happy with the new enclosure on several aspects as I am setting up the TRY PDs/camera.

1. I strongly feel the o-rings should be glued/fixed to the plastic box atleast at some points. Even if we replace the current thin one with a thicker tubing, it takes forever to get the o-ring into the groove when it slips out. Also if it slips from the groove, it falls through the optical path and there are chances of burning the tubing when the NPRO is ON.

2. With the transparent tables, the cameras are sensitive to the room lights. I had to switch off the room lights/use ND filters to see a nice beam at the TRY camera.

3. The lids are heavy...might be a good way to train....but removing and putting them back will definitely increase the pain in getting the green aligned to the arms atleast until we have the PZTs set up.

  8418   Fri Apr 5 01:28:56 2013 ManasaUpdate40m UpgradingEndtable upgrade for auxiliary green laser : populating the table

I started populating the end table; the TRY path to start with. I found that I need to redo the cables/electronics layout around the table as we have only one cable feedthrough hole with the new box right now. I need another hand with this and will have Annalisa help me tomorrow.

P.S. I misaligned PRM and restored ETMY to get TRY flashes. I tweaked ETMY to see strong TEM00 flashes.

Old slider positions on medm screen in case we need to restore them:

        TT1    TT2     ITMY    ETMY

P   -1.3586  0.8443   0.9114   -3.7693

Y   0.3049   1.1507  -0.2823  -0.2761

 

  8419   Sat Apr 6 09:21:36 2013 ranaUpdate40m UpgradingNot a fan of the new plastic box yet

 

 1) We still need to drill and install the thumbscrew latches which secure the lids to the table. We cannot use the tables as an acoustic enclosure with loose lids.

2) For the camera issue, the idea is to put the longpass filters on the front of the cameras: then they are only sensitive to light with wavelength > 800 nm.

3) Whenever any interferometer work is happening the light switches must be in the positions which have been marked on them (and which most everyone ignores foolishly). We have never been insensitive to the room lights; the black table enclosures just give us a false sense of security. Room lights impact the interferometer noise.

  8423   Mon Apr 8 16:37:26 2013 SteveUpdate40m UpgradingETMY enclosure wall transmission

 

 Enclosure cover #1 transmission measured  in 1064 nm,  156 mW,  P polarization and beam size ~ 1 mm

As condition:  fully assembled, protective layer removed, tinted- adhesive activated on yellow acrylic on top of each other.

T = 1.2 % in 20 minutes exposure test. This agrees with the test measurement of 6-18-2012

There is a reflected  2-3 cm circular glare that is barely visible on sensor card. It is well below 1 mW level

As we are installing the NPRO with ~350 mW of power we have to address what additional shield should be installed.

The June 2012 test with 1W power burned through of the 3 layer  IR coated films in 3-4 hours.

We 'll use Aluminum shields in the high power path till we come up with better solution.

  8425   Tue Apr 9 00:15:18 2013 ManasaUpdate40m UpgradingEndtable upgrade for auxiliary green laser : populating the table

[Den, Annalisa, Manasa]

The Alberto laser was moved from the PSL table. The height of the heat sink rendered a beam height of only 3 inches. I did not want to deal with changing beam height at the table. So, we went ahead and used the old heat sink. I used the beam scan to make measurements of the beam width to match my mode-matching calculations and found some mismatch with the measurements done earlier. So I will measure the beam width again before alignment.

I will also have to change the layout because of the supporting posts that have come up with the new box. Annalisa is doing a COMSOL model to check what the thickness of these supporting posts should be so that the box stays stiff.

  8427   Tue Apr 9 00:32:57 2013 ManasaUpdate40m UpgradingEndtable upgrade for auxiliary green laser : TRY temporarily in place

The TRY path on the end table is temporarily in place to help IFO locking.
The Y arm transmission was steered to get TRY back on the PD and the camera. I found that TRY is a couple of inches off in yaw at the end table (comparing to the CAD layout and the earlier layout) and I believe it is because of the changes in input pointing.
I've used a Y1 mirror to steer the Y transmission to an R98% BS. The reflected beam falls on PDA520 and the transmitted beam is steered to the camera. The earlier normalization of TRY is no more valid as the power distribution at the PD has changed.

  8430   Tue Apr 9 08:37:54 2013 SteveUpdate40m UpgradingEndtable upgrade for auxiliary green laser : TRY temporarily in place

Quote:

The TRY path on the end table is temporarily in place to help IFO locking.
The Y arm transmission was steered to get TRY back on the PD and the camera. I found that TRY is a couple of inches off in yaw at the end table (comparing to the CAD layout and the earlier layout) and I believe it is because of the changes in input pointing.
I've used a Y1 mirror to steer the Y transmission to an R98% BS. The reflected beam falls on PDA520 and the transmitted beam is steered to the camera. The earlier normalization of TRY is no more valid as the power distribution at the PD has changed.

Temporary  acrylic wind guard added between enclosure and ETMY transmission window to help IFO locking

  8432   Tue Apr 9 21:27:48 2013 JenneUpdate40m Upgrading TRY temporarily in place

Quote:

I've used a Y1 mirror to steer the Y transmission to an R98% BS. The reflected beam falls on PDA520 and the transmitted beam is steered to the camera. The earlier normalization of TRY is no more valid as the power distribution at the PD has changed.

 To take this into account, last night, I reduced the TRY gain by a factor of 2.  This is not exactly correct - when the layout is finalized we need to figure out what the pickoff situation used to be (we think, based on the Xend, that it could have been 0.5*0.9), and do the correct normalization.

  8436   Wed Apr 10 14:25:04 2013 ManasaUpdate40m UpgradingEndtable upgrade for auxiliary green laser : LWE Alberto laser beam profile

I measured the beam profile of the Alberto laser (that will be the ETMY end laser) as I found the data inconsistent with the measurements done earlier.

Method

The laser was set to nominal current (ADJ =0) and the output measured 330mW. I used a 99% BS and measured the beam profile of the transmitted light at several points along propagation using Beamscan. I am attaching the data and matlab script for the fit for future reference.

LWE_Alberto_BP.png

Attachment 2: beam_waist.zip
  8458   Wed Apr 17 02:20:13 2013 ManasaUpdate40m UpgradingEndtable upgrade for auxiliary green laser : progress

 

Assembly progress:

1. ETMY oplev setup has been put together. Because of the shift in the TRY path, I had to modify the oplev path on the table as well.

TRY_OPL.jpg

2. Green laser setup coming together:
    (i) Used a HWP after the NPRO to convert s-polarization to p-polarization. (Verified by introducing a PBS after the HWP and then removed later).
    (ii) Lens focuses the beam into the Faraday.
    (iii) Used steering mirrors to align the beam to the faraday. With 320mW before the Faraday, I was able to get 240mW after the output aperture. The spec sheet for the faraday specifies a 93% transmission; but what I measure is only 75%.

GRY.jpg

 

  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
  8473   Mon Apr 22 19:48:56 2013 JenneUpdate40m Upgrading4 pins enough?

Are 4 of these spring loaded pins enough?  I'm not sure how one pin can hold 2 lids at each point.  It seems like we need 8 pins.

  8475   Tue Apr 23 15:00:20 2013 JenneUpdate40m Upgrading4 pins enough?

Quote:

Are 4 of these spring loaded pins enough?  I'm not sure how one pin can hold 2 lids at each point.  It seems like we need 8 pins.

 Steve has explained to me that the pins will go in between the 2 lids, with a big washer, so that one pin holds both lids at the same time.  4 is the right number.

  8486   Wed Apr 24 15:27:59 2013 ManasaUpdate40m UpgradingEndtable upgrade for auxiliary green laser : progress: New layout

Layout that will be improved upon over the next few days.

Things that need to be updated:
1. Waist size at all optics
2. Beam size at detectors and choice of lenses
3. IPANG & green PD proposed positions

 ETMY_endtable_New.png

  8522   Thu May 2 01:19:41 2013 ManasaUpdate40m UpgradingEndtable upgrade for auxiliary green laser : progress

I started to put together optics at the endtable. I am attaching the layout with the green blocks showing the optics that are assembled and will not be moved henceforth unless somebody contradicts.

1. Power after HWP = 314mW
    Power before faraday = 310mW
    Power after faraday = 300mW (the power loss while aligning the faraday earlier was due to the AR coating on the focusing lens before the faraday - it was AR coated for visible and that accounted to the power lost)

2. Since we do not know the length of TGG inside faraday, I measured the beam profile after the faraday so that I can trace the beam without any errors to calculate exact mode matching solutions.

3. The NPRO beam seems to be obviously elliptical as seen on the IR card and also from beam profile measurement. So we cannot skip including cylindrical lenses in the layout.

ETMY_0502.png

 

  8543   Tue May 7 19:06:45 2013 ManasaUpdate40m UpgradingEndtable upgrade for auxiliary green laser : progress

I have updated the waists (W)  and beam diameters (D) at 1064nm optics on the endtable.

I am not able to locate the characteristics of QPD-Y and oplev PD and hence took the beam diameter to be half of the detector surface area to determine their positions.

Beam diameter on PDA520 used for TRY was calculated using the transimpedance and responsivity of the PD from an old elog in 2004.

ETMY_endtable_New.png 

  8556   Thu May 9 01:36:32 2013 ManasaUpdate40m UpgradingEndtable upgrade for auxiliary green laser : progress

Progress with end table:

Parts in green show assembled optics that will not require any changes. Parts in yellow are in place but will need either change of lenses in their optical path or change in position.

0509.png 

  8560   Thu May 9 22:29:23 2013 ManasaUpdate40m UpgradingEndtable upgrade for auxiliary green laser : progress

[Annalisa, Manasa]

More optics have been put on the table. Direction of the rejected beam from the 532nm faraday estimated to be ~1.7 deg along -y axis.

Transmon QPD, TRY and camera have beams on them for locking Y arm. Oplev configuration is waiting for it's lens to arrive.

 

  8561   Fri May 10 20:05:21 2013 AnnalisaUpdate40m UpgradingEndtable upgrade for auxiliary green laser : progress

I rotated some mounts along the green beam path, and I started aligning the beam again.

The beam is aligned up to the waveplate just before the doubler crystal, even if I couldn't reach more than 88% transmission for the Faraday. Next week I will finish the alignment and I'll put the lenses that Manasa already ordered.

 

  8565   Mon May 13 21:35:55 2013 AnnalisaUpdate40m UpgradingEndtable upgrade for auxiliary green laser : progress

Yend table - Current status

OPLEV

Today the 2m focal length lens along the oplev path (just after the laser) has been added. In Manasa's layout it allows to have a beam waist of 3.8mm on the OPLEV QPD, even if it seems to be smaller.

The laser is closer to the box wall than the layout shows (it's on the line n.1 instead of line n.9), so maybe it has to be moved in the position shown in the layout, as Steve suggests, to leave empty space just before the window.

Rana suggests a 2mm diameter beam on the QPD, so a new calculation has to be done to add a second lens.

GREEN

The beam has been aligned until the doubler, but after the crystal it it has a small tilt, so a better alignment has to be done.

Moreover, the beam waist has to be measured after the Faraday for the green, in way to choose the focal length of the lenses necessary for the mode matching.

Then the three steering mirrors to send the beam into the arm have to be put.

TRANSMON PATH

A lens which has to be put on the Transmon path (already ordered) has to be added, and the beam alignment on the QPD-y and on the PDA520 has to be done.

ELOG V3.1.3-