LIGO Document E1900199-v2

ETM Polishing Specification for re-polish

Document #:
Document type:
E - Engineering documents
Other Versions:
08 Jul 2019, 16:01
Advanced LIGO ETM Polishing Specification
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Notes and Changes:
Change Log from -v1:

1. E1900199 changes to revision 2, DCN, E1900200 goes to -v2 as well
2. Removed the reference to the assembly document, polisher will fabricate from “earless” substrate form.
3. "Polishing Process” topic is added with the following language,

"Ion Beam Figuring removal processes should be designed to minimize the probability of defects in the center 160 mm diameter”

4. Also incorporated previous language regarding grit sizes into this new section.
5. Added “is done in a dark room” to the Defect Inspection Method #1.
6. Removed Scratch and Point Defect Inspection Method #3, (microscope) as this brought no new insight to the inspection process for aLIGO and involves capital and manpower investment:
Method #3. "An inspection is then carried out with a dark or bright field microscope, with 5x objective at four positions at each of the following locations:

• Within 10mm of the center of the surface.
• Equally spaced along the circumference of a centered, 60 mm diameter circle.
• Equally spaced along the circumference of a centered, 120 mm diameter circle"

7. Changed data delivery to electronic form.
8. Changed alternate defect inspection to apply to method #2 defect inspection (this just says that they can use the microroughness measurement to quantify the defects instead of the 6x eyeglass.

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