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ID Date Author Type Categorydown Subject
  4214   Thu Jan 27 21:10:47 2011 OsamuUpdate40m UpgradingCalibrated noise of green

I calibrated noise spectrum of green lock.

1. Measurement of conversion factor of ADC input from V to ct:

As a preparation, first I measured a conversion factor at ADC input of C1;GCX1SLOW_SERVO1.

It was measured while the output of AI ch6 as the output of C1;GCX1SLOW_SERVO2 with 1Hz, 1000ct(2000ct_pp) was directly connected into AA ch7 as the input of C1;GCX1SLOW_SERVO1. Amplitude at the output at AI ch6 was 616mVpp measured by oscilloscope, and C1;GCX1SLOW_SERVO1_IN1 read as 971.9ct_pp. So the conversion factor is calculated as 6.338e-4[V/ct].

2. Injection of a calibration signal:

When Green laser was locked to cavity with fast PZT and slow thermal, I injected 100Hz, 1000ct EXC at ETMX ASL. The signal was measured at C1:GCX1SLOW_SERVO1_IN1 as 5.314ct_rms. It can be converted into 3.368e-3Vrms using above result, and then converted into 3368Hz_rms using PZT efficiency as 1MHz/V. This efficiency was obtained from Koji's knowledge, but he says that it might have 30% or higher error. If somebody get more accurate value, put it into the conversion process from V to Hz here.

3. Conversion;

Frequency of green f=c/532nm=5.635e14[Hz] is fluctuating with above 3368Hz_rms,so the fluctuation ratio is 3368/5.635=5.977e-12, and it corresponds to length fluctuation of 37.5m. So, cavity fluctuation will be 5.977e-12*37.5=2.241e-10m_rms by 100Hz, 1000ct EXC at ETMX ASL.

4. Results;

Finally, we knew 5.314ct corresponds to 3368Hz and 2.241e-10m, so conversion factor from ct to Hz and ct to m are ;

633.8[Hz/ct] @ C1:GCX1SLOW_SERVO1

4.217e-11[m/ct] @ C1:GCX1SLOW_SERVO1

 

5. Calibration:

You can measure green noise spectrum at C1;GCX1SLOW_SERVO1_IN1 during lock,  and mutiply above result to convert Hz or m.

This calibration is effective above corner frequency of slow and fast servo around 0.5Hz and UGF of fast servo around 4kHz.

I show an example of calibrated green noise.

20110127_Calibrated_grrennoise.jpg

20110127_Calibrated_grrennoise.pdf

Each color show different band-width. Of course this results of calibration cactor does not depend on band-width. Noise around 1.2Hz is 6e-8Hz/rHz. It sounds a bit too good by factor ~2. The VCO efficiency might be too small.

 

Note that there are several assumptions in this calibration;

1. TF from actual PZT voltage to PZT mon is assumed to be 1 in all frequency. Probably this is not a bad assumption because circuit diagram shows monitor point is extracted PZT voltage directly.

2. However above assumption is not correct if the input impedance of AI is low.

3. As I said, PZT efficiency of 1MHz/V might be wrong.

 

I also measured a TF from C1:SUS-ETMX_ALS_EXC to C1:GCX1SLOW_SERVO1_IN1. It is similar as calibration injection above but for wide frequency. This shows a clear line of f^-2 of suspension.

20110127_TF_ETMXSUSEXC_to_PZTOUT.pdf

 

Files are located in /users/osamu/:20110127_Green_calibration.

  5696   Wed Oct 19 12:25:58 2011 SureshUpdate40m UpgradingActive Tiptilts from LLO moved to clean shelf along X arm

I have moved the active tip tilts that we brought over from LLO to the Clean Bureau along the X arm (closest to the ETMX). There are two tip tilts and a pack of spare parts.

  5697   Wed Oct 19 13:45:11 2011 SureshUpdate40m UpgradingActive Tiptilts from LLO moved to clean shelf along X arm

I have moved the active tip tilts that we brought over from LLO to the Clean Bureau along the X arm (closest to the ETMX). There are two tip tilts and a pack of spare parts.  I am sure that the tip tilts are clean, packed in the clean room at LLO.  I am not sure whether the spares are clean.  I have kept them together for now.

We need to open one of the Tip tilt packages to be sure what we have got.

  7090   Mon Aug 6 11:07:06 2012 ManasaUpdate40m UpgradingOptical layout updated

ACAD files of the 40m optical layout have been updated as per the vent in Aug 2011.

Files are available at the 40m svn docs-->Upgrade12-->Opt_Layout2011.

 

  7125   Wed Aug 8 20:51:56 2012 ManasaUpdate40m UpgradingOptical layout updated

Quote:

ACAD files of the 40m optical layout have been updated as per the vent in Aug 2011.

Files are available at the 40m svn docs-->Upgrade12-->Opt_Layout2011.

 

 To ease the pain of hunting files, optical layout ACAD files have been moved to a new directory 40M_Optical Layout in the repository. Relevant files from directories Upgrade12 and upgrade 08 will be moved to "40M_Optical Layout" very soon and eventually these old directories will be removed. 

  7222   Fri Aug 17 18:49:55 2012 ManasaUpdate40m UpgradingOptical layout updated

Quote:

Quote:

ACAD files of the 40m optical layout have been updated as per the vent in Aug 2011.

Files are available at the 40m svn docs-->Upgrade12-->Opt_Layout2011.

 

 To ease the pain of hunting files, optical layout ACAD files have been moved to a new directory 40M_Optical Layout in the repository. Relevant files from directories Upgrade12 and upgrade 08 will be moved to "40M_Optical Layout" very soon and eventually these old directories will be removed. 

Changes mentioned by Koji and Steve have been updated to the files (except for the cable connector which have been added but whose part number has to be found to match accurately with the current layout). The file in the directory should now match the current setup after the last vent Aug 2011.

Let me know if you find any mismatch between the current setup and the layout.

Plans about new installations/reconfiguration during the new vent will be carried out in a separate file.

  7245   Tue Aug 21 18:23:58 2012 ManasaUpdate40m UpgradingETMX table layout

Optical layout of the current endtable at ETMX has been updated in the svn repository (directory: 40M_Optical Layout). This layout will help in redesigning the table for the proposed replacement.

Some part numbers of mounts/optics are missing and will be updated once I find them. If you find anything wrong with the layout, do let me know.

 

  7354   Thu Sep 6 19:21:58 2012 ManasaConfiguration40m UpgradingBaffle problem

For the current baffle (dia. 40mm) centered along the beamline place at 1.77" from the test mass, the baffle will allow ~8.6mm visibility on the camera from the center of the test mass (in case of ETMY).

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

  7359   Fri Sep 7 11:58:12 2012 ManasaConfiguration40m UpgradingBaffle problem

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; 

  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.

  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.

 

 

  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.

 

  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.

  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.

  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.

  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.

 

  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

  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.

 

  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

  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

 

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