LIGO Document T0900367-v1

Ambient Magnetic Field Coupling to Quadruple Suspension Stainless Steel Parts

Document #:
LIGO-T0900367-v1
Document type:
T - Technical notes
Other Versions:
Abstract:
Residual magnetic flux density and ferromagnetism in the stainless steel members that are part the upper stages of the quadruple suspension will cause a noise coupling with the ambient magnetic field and field gradient. The residual magnetic flux density and ferromagnetism are a consequence of work history of the material (rolling, machining, etc.). Unless the material is brought above the Curie temperature (above ~800C) these residual magnetic properties will remain. In addition, the maraging steel, cantilevered, spring blades are also ferromagnetic and will force couple to the ambient magnetic field. The purpose of this note is to make approximate estimates of the magnitude of these noise coupling terms.

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