LIGO Document T080307-v6

Initial Alignment System (IAS) Design Requirements Document (DRD)

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Document type:
T - Technical notes
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01 Feb 2011, 12:26
23 Jan 2011, 17:37
The purpose of this document is to specify the requirements for the Initial Alignment System (IAS) for Advanced LIGO, which is a component of the Auxiliary Optics System (AOS).
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Notes and Changes:
Clarified angular accuracy requirement in section 3.3

4/26/2013 D. Coyne: The positional and angular alignment accuracy requirements set forth in T0800307-v6 are based upon 10% of the OSEM range, the criteria used in iLIGO. However, for aLIGO, we can tolerate using more of the DC range of the OSEMs, say 30% to 40%. Using this revised criteria the requirements for SR2 alignment (for example) are as follows (using 20% of range for positional and 20% for angular):
6.2.4 SR2 vertical: +/- 3.4 mm
6.2.5 SR2 horizontal: +/- 5.1 mm
6.2.8 SR2 yaw: +/- 820 microrad
6.2.9 SR2 pitch: +/- 520 microrad
This document should be changed to reflect this relaxation in the alignment accuracies for SR2, as well as similar relaxed alignment accuracies for the other SRC optics.

5/3/2013 D. Coyne: Similarly for SR3 and SRM, but where the decentering (vertical & horizontal) is limited by diffraction (clipping) considerations:

6.3.3 SR3 vertical: +/- 3.0 mm
6.3.4 SR3 horizontal: +/- 3.0 mm
6.3.6 SR3 yaw: +/- 200 microrad
6.3.7 SR3 pitch: +/- 560 microrad

6.4.3 SRM vertical: +/- 3.0 mm
6.4.4 SRM horizontal: +/- 4.6 mm
6.4.6 SRM yaw: +/- 820 microrad
6.4.7 SRM pitch: +/- 520 microrad

where the section references above are to sections within the LHAM4 & LHMA5 alignment procedure (E1100784-v5).

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