LIGO Document E0900364-v10
- Metal components intended for use in the Adv LIGO Vacuum System
- v10: Includes additional information on tapped holes in section 4.8.
v9 includes re-addition of the following references in the scope section: -
(LIGO-E1000083), Specification for Enameled Steel Sheet to be used in the LIGO Ultra-High Vacuum System.
(LIGO-E0900048), Welding Specification for Weldments used within the Advanced LIGO Vacuum System.
as these were accidentally removed between v7 and v8. v8 still had a single reference to (LIGO-E0900048) but it was buried.
Pending for -v10:
Section 4.1 ('Metal components intended for use in the Adv LIGO Vacuum System') requires that materials must be of domestic (United States) origin. The restriction to US sources is not specific to US funded and sourced components; The reason for the restriction to US sources for metals is a long history of inferior metals from some countries. Add allowance for metals purchased with DFARS certification. DFARS stands for Defense Federal Acquisition Regulation Supplement. DFARS is a set of restrictions for the origination of raw materials intended to protect the US defense industry from the vulnerabilities of being overly dependent on foreign sources of supply. The term DFARS compliant refers to materials (metal or otherwise) that come from domestic or NATO sources. However, there are countries included in DFARS that are not members of NATO. Note that substitutions and exceptions may be obtained in writing from LIGO Systems Engineering, in advance of manufacturing any components. The exception should be based on some assurance of material quality (no contaminants, no voids, etc.).
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