aLIGO HAM-ISI, Test Report, Phase I: Assembly Validation, LLO Unit #4 (HAM4)

Document #:

LIGO-E1000328-v2

Document type:

E - Engineering documents

Abstract:

This Unit#4 has been built between May and July 2011, and was tested immediately afterward.
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A few minor issues were found during the testing of this unit 4. The known issues are summed up here:
- Sensor gaps not recorded on the jig
- CPS 12064 has an Amplitude Spectral Density too high at 0.1Hz. This was previously noted by Rich M. as not so good but acceptable.
- Blade Spring Profile: the difference of height between the root and the tip of the blade is slightly bigger than 15 mils for Blade 1. This is thought as the best compromise that can be found with the shims available, while keeping the optical table leveled.
- GS-13 powerspectra on the locked table shows slightly more signals than expected around 100 mHz, but since the criteria was arbitrarily defined to compare with what we obtained on previous units, we passed that test.
- Linearity Test: the variation of the slope compared to the average slope, is slightly bigger than 1% for H2 & V1. The difference was low enough that it is dimmed not to be an issue.

Overall the system appeared really consistent, and behaved as expected.

Files in Document:

• E1000328 aLIGO HAM-ISI -LLO Unit 4 - V2.pdf (6.9 MB)

Other Files:

• E1000328 aLIGO HAM-ISI -LLO Unit 4 - V2.doc (7.1 MB)

Topics:

• Seismic Isolation
• Final Design

Authors:

• Celine Ramet

Keywords:

HAM ISI test LLO HAM4

Notes and Changes:

Few typos corrected

Referenced by:

• LIGO-E1100996: aLIGO HAM-ISI, Phase I Testing Reports