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Message ID: 2811     Entry time: Tue Sep 14 16:43:11 2021
Author: shruti 
Type: Update 
Category: Optics 
Subject: Debonding and bonding mirrors to silicon cantilevers 

[Shruti, Koji, Aaron]

Today Koji guided us to (1) remove the mirror I had contacted to the cantilever that later broke, and (2) clean and contact the second flat (1550 nm wavelength coated) mirror to another cantilever using cryo varnish.

(1) De-bonding the mirror

After my failed attempts at using methanol and acetone along the edges followed by soaking the contacted-to-silicon optic in isopropanol, today we were finally able to de-bond the mirror by soaking in methanol. We used two washers to raise the optic from the aluminum surface and folded foil pieces to keep everything in place. The setup shown in Attachment 1 was covered with another aluminum foil dish and let sit. It took at least an hour of soaking to completely de-bond.

Koji then drag wiped the optic with pure isopropanol to clean any remaining residue and cryo-varnish hairs.

 

(2) Bonding a different mirror to a cantilever

First we tested drag wiping the broken silicon cantilever with methanol and isopropanol. Then we selected a reasonably looking cantilever that was not chipped at the edges, though it had an uneven surface, and drag-wiped both surfaces with isopropanol.

We drag-wiped the HR surface of the optic a few times and then placed it on the portion of the cantilever that had the square etched-out region. While Koji held the mirror in place I applied cryo-varnish to four points around the mirror. This is now set to dry.

 

 

Update: Photos are available on the ligo.wbridge google drive.  I uploaded everything, but could pare down to save drive space. 

Attachment 1: varnishdissolve.pdf  17.189 MB  Uploaded Tue Sep 14 17:55:20 2021  | Hide | Hide all
varnishdissolve.pdf
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