Conceptual Design of a Larger Beamsplitter Suspension

Document #:

LIGO-T1400296-v10

Document type:

T - Technical notes

Abstract:

Design of a Larger Beamsplitter Suspension.

Some considerations from MATLAB modelling and blade redesign.

8th April 2019. Note added in v10. A larger beamsplitter is now part of the design for A+. This document now serves as a starting place for the A+ design. As such it has been renamed “Conceptual Design…”

Files in Document:

• T1400296-v10_larger_beamsplitter_suspension.pdf (file is not accessible)

Other Files:

• BLADE_BS_larger_mass_60mm.xls (file is not accessible)
• BLADE_BS_larger_mass_60mm_Middle_unchanged.xls (file is not accessible)
• BLADE_BS_larger_mass_73mm.xls (file is not accessible)
• Copy of BLADE_BS_aLIGO_values.xls (file is not accessible)
• T1400296-v10_larger_beamsplitter_suspension.docx (file is not accessible)

Topics:

• Conceptual Design
• Suspensions
• Basic R&D

Authors:

• Norna Robertson
• Mark Barton

Keywords:

larger beamsplitter revised suspension conceptual design

Notes and Changes:

v1 = first draft, v2 - added section on blade redesign
v3 - more on blades.
v4 - section 6.5 added
v5 - fig 8 revised (r1 increased in same way as r2 and r3)
v6 - added thermal noise prediction from Mark Barton's Mathematica model, and appendix with suspension parameters.
v7 - section 6.6 added
v8 - section 8 and Appendix B added, following discussions with Joe O'Dell at Rutherford Appleton Lab, Sept 2014.
v9: changed title (removed First thoughts..")

March 2019. Norna added another excel sheet for blade dimensions.

Now have

1) aLIGO design,
2)new optic mass 450 mm x 60 mm with middle mass unchanged from aLIGO
3)new optic mass 450 mm x 60 mm with middle mass scaled to same size
4)new optic mass 450 mm x 73 mm with middle mass scaled to same size.

These files should only be used as guides to choose blade dimensions, frequencies and stress levels. They assume ideal triangular shape. The deflection and radius of curvature columns and graph have not been used and should be ignored.

v10: 8th April 2019. changed title to "Conceptual design.." Added note in introduction, repeated in abstract above

Related Documents:

• LIGO-G1400804: Risk Reduction Work on Advanced LIGO Suspensions

Referenced by:

• LIGO-T1400750-v1: aLIGO Mechanical Design Considerations for a Larger BS Optic