Test Mass Transmissibility

Document #:

LIGO-T970191-v1

Document type:

T - Technical notes

Abstract:

Although the internal resonances of the test mass are beyond the Length Sensing and Control (LSC) control bandwidth, any (unintended) magnetic coil drive currents at the test mass resonances will be amplified by the high Q of the test mass. The transmissibility of applied force at the magnet positions to displacement response of the front surface of the LIGO test mass is calculated via finite element analysis. Based upon the transmissibility, the gain attenuation required in the length control system, in order to prevent driving the test mass motion at resonance beyond acceptable limits, may be established.

Files in Document:

• T970191-03.pdf (482.3 kB)

Topics:

• Core Optics
• Modelling

Authors:

• Dennis Coyne

Keywords:

S5 iLIGO Test Mass Resonances Rigid Body

Notes and Changes:

Imported from old DCC. Equivalent to Version 3.

Referenced by:

• LIGO-P0900120-v17: Calibration of the LIGO Gravitational Wave Detectors in the Fifth Science Run (S5 Calibration Paper)