LIGO Document M0900034-v4

RODA: Use of SmCo and NdFeB Magnets in Advanced LIGO Suspensions

Document #:
LIGO-M0900034-v4
Document type:
M - Management or Policy
Other Versions:
Abstract:
RODA to document decision to use SmCo magnets rather than NdFeB magnets for the suspensions of Advanced LIGO.

Version v2 is modified to document decision to use SmCo magnets at the more sensitive places in the Adv LIGO suspensions and NdFeB magnets elsewhere. It also documents where BOSEMS and LIGO 1 OSEMs are used.

Version v3 is modified to note that SmCo will be used everywhere that dynamic control signals are applied.

Version v4 is modified with two updates:
1) revised size of the HLTS lowest mass magnets, now 2 mm x 0.5 mm, making them the same as used on the lowest mass of the HSTS.
2) a statement that for eddy current damping applications NdFeB magnets will be used.

Files in Document:
Other Files:
Notes and Changes:
It should be noted that although the RODA says that SmCo magnets do not require Ni plating, after experience of handling them we took the decision to have all our SmCo magnets plated. Thus all SUS aLIGO magnets (NdFeB and SmCo) are Ni-plated. (Norna 19 May 2014.)

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