Tracking temporal variations in the DARM calibration parameters.

Document #:

LIGO-T1500377-v8

Document type:

T - Technical notes

Abstract:

In this document we describe a method for calculating frequency independent changes in the DARM actuation and sensing functions and the coupled-cavity pole frequency using one x_ctrl and one Pcal calibration line.

Files in Document:

• -v8 .pdf file (tracking-temporal-variations-8.pdf, file is not accessible)

Other Files:

• independent actuation kappas (pdf) (independent-actuation-kappas_0-02.pdf, file is not accessible)

Topics:

• Calibration

Authors:

• Darkhan Tuyenbayev
• Richard Savage
• Kiwamu Izumi
• Jeffrey Kissel
• Sudarshan Karki

Notes and Changes:

Updated fig. 1 to accurately locate the "minus sign" in the loop.
Corrected equations.
Updated table two by swapping the line 1 and line 3 frequencies to reflect the error made when implemented at LLO.
Changed minus to plus in equations 5, 7, 9, and 19 to reflect the change in the placement of the minus sign in the loop diagram.
Added the beginning of Sec. 5, the for the calculation of h(t).

Related Documents:

Referenced by:

• LIGO-P1600063-v11: Improving LIGO calibration accuracy by tracking and compensating for slow temporal variations