DCN for update of End Test Mass specifications - change radius of curvature requirement

Document #:

LIGO-E2000633-x0

Document type:

E - Engineering documents

Abstract:

Section: Surface Figure, measured over the central 160 mm diameter
Change
from: 2245 -5+15 m
to: 2240 ± 10 m

Change
ROC precision
From: R ± 3 m where 2240 m ≤ R ≤ 2260 m for all ETM optics
To: R ± 3 m where 2230 m ≤ R ≤ 2250 m for all ETM optics

Reason for change: symmetric tolerance yields a better outcome for LIGO. Vendor confirms that they will deliver at the midpoint of the tolerance whether symmetric or asymmetric.

The analysis for this change is presented in G2001920

Files in Document:

None

Topics:

• Procurements
• A+ Project
• Core Optics
• Operations

Authors:

• GariLynn Billingsley

Keywords:

ETM

Notes and Changes:

There is no change to the ETM drawing, D080658, it stands at v5

Related Documents:

• LIGO-E080512-v6: E080512_ETM_Polishing_Specification
• LIGO-G2001920: Custom polish figure for O4 ETMs