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Entry  Mon Apr 16 16:21:01 2012, tara, Notes, optic, windows for vacuum chamber 
    Reply  Tue Apr 17 19:51:54 2012, tara, Notes, optic, windows for vacuum chamber IMG_0757.jpg
       Reply  Thu Apr 19 03:12:23 2012, tara, Notes, optic, windows for vacuum chamber 
          Reply  Sun Apr 22 23:09:38 2012, tara, Notes, optic, windows for vacuum chamber 
             Reply  Mon Apr 23 16:52:16 2012, tara, Notes, optic, windows for vacuum chamber 
                Reply  Wed Apr 25 10:44:29 2012, Frank, Notes, optic, windows for vacuum chamber 
                   Reply  Thu Apr 26 08:35:57 2012, steve, Notes, optic, windows for vacuum chamber 
                      Reply  Fri Apr 27 08:46:24 2012, Frank, Notes, optic, windows for vacuum chamber 
                         Reply  Tue May 1 20:37:16 2012, tara, Notes, optic, windows for vacuum chamber 
                            Reply  Fri May 11 17:52:17 2012, tara, Notes, optic, windows for vacuum chamber O-Rings.pdf.zip
                               Reply  Wed May 16 22:27:13 2012, tara, Notes, optic, windows for vacuum chamber 2_small_window.PDFblank_10_wedge.PDF
                                  Reply  Mon May 21 16:53:38 2012, tara, Notes, optic, windows for vacuum chamber edit_blank_10_wedge.PDFwindow_assembly.PDFwindow_assembly2.PDF
                                     Reply  Wed May 23 15:04:53 2012, steve, Notes, optic, windows for vacuum chamber 
Message ID: 940     Entry time: Thu Apr 26 08:35:57 2012     In reply to: 938     Reply to this: 943
Author: steve 
Type: Notes 
Category: optic 
Subject: windows for vacuum chamber 

Quote:

I don't know how you gonna make the knife edge on the 10" flange of centered and wedged! If you put the small CF flanges on the big one you have parasitic cavities between the window and the cavity even if the window is wedged (only the outside is tilted relative to the flange, the inside is parallel by design. I also suggest going for a metal seal, but not copper as getting those knife edges will be complicated and expensive i guess. So why not using indium or the other single-use metal seal replacement techniques for o-rings available and you only need a flat surface on the big flange and a few tapped blind holes?

Quote:

I asked Steve about the choices, he thought the Thorlabs window should be ok for us.

      What Steve suggested are:

  • The seal between the 10" blank and the windows should be copper seal, (the window already comes with knife edge),so
  • the blank will have knife edge seals for two small windows as well.
  • Thorlabs window does not have an o-ring between the window frame and the optic, we should add the o-ring between them to avoid a direct metal-glass contact.

About the blank with two openings for beam access, he said a vacuum company could do it for us. I'll make a drawing and get a quote from Nor-Cal and MDC. I have to specify that the blank will be for ultra high vacuum system (UHV).

Quote:

For small window option, I can either have it made from scratch ( based on LIGO's drawing) or buy the commercial windows from Thorlabs. Here I listed down all pros and cons for each choice as I discussed it with Frank. I 'll ask Steve tomorrow for his opinions.

 == Using Thorlabs 2.75" OD windows:==

       Pros

  • easy to replace for damaged optics,
  • ready in short time (parts are in stock)
  • minimum time on machine shop
  • The thickness of the window is only 0.63", It should be able to fit in the set up which has ~ 1" clearance.

      cons:

  • Have more rubber seals in the system due to the design, I'll check Cryo:194 to see what will be the minimum pressure we need.

==Making custom parts (like LIGO, see quote window)==

     Pros:

  • There are only one o-ring used for each window (better vacuum pressure)

     cons:

  • Spend more time on designing/machining, probably more money for making the parts as well.
  • Take longer time if we need more spare pieces.
  • The available space for the window is quite limited (1"). If we follow what Zach did for Gyro, it is already to thick for our setup

Quote:

 

I'm searching DCC for window/viewport examples. The following drawings give me some ideas how to make a window for our setup.

 TCS viewports details

double viewports

septum window flange

 

 

 

 Request 2 degrees off set the the 2.75"cf knife edge and tapped holes on the 10" flange.  The location is custom anyhow. You can gain some space this way.  Or can you tip your chamber? 

Check how parallel you cavity is with your chamber

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