LIGO Document L1200261-v2

Executive Summary of the One Arm Test

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L - Letters and Memos
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The One Arm Test was the first integration phase of the Advanced LIGO project. It took place at LIGO Hanford Observatory using the Y-arm cavity of H2, starting on June 21, 2012, and ending during the week of September 10, 2012. The applicable integration planning document can be found as T1100080.
The One Arm Test was a great success. Establishing the basic functionality between different subsystems was straight forward with only small problems—a significant and refreshing improvement compared to the first steps of initial LIGO commissioning. As an example, finding the initial beam and getting the arm cavity locked only took days, compared to the 3 months for locking the initial LIGO mode cleaner.
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Notes and Changes:
The following goals of the one arm test have been achieved during the HIFO-Y test (see L1300176):
- Cavity alignment fluctuations/SEI/SUS
- Cavity length control/SEI/SUS/ALS
- ALS: Ability to control frequency offset between 1064 nm and 532 nm resonances at the 10 Hz level
- ALS: Relative stability of the 1064 nm and 532 nm resonances at the 10 Hz level for frequencies below 0.5 Hz
- Controls/ISC: Fully automated cavity locking sequence; long term cavity locking
Still open:
- Controls/SUS: Decoupling of length-to-angle at the level of 0.05 rad/m or less, for frequencies below 0.5 Hz

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