LIGO Document E1500172-x0

Summary of COC fabrication acceptance review

Document #:
Document type:
E - Engineering documents
COC fabrication acceptance review team: Peter Fritschel (chair), Brian O'Reilly, Hiro Yamamoto

The review team met with GariLynn B on February 3, 2015. Dennis C and Eric G also attended this meeting. The meeting resulted in requests for a number of document updates and other actions:

  • Update the Design Requirements Document

  • Update the Final Design Document

  • Create a clear, uniform approach to documenting waivers for vendor deliveries

  • File in the DCC any software, manuals, etc pertinent to the Caltech metrology facilities

  • Document the ITM substrate polishing issue, in which the transmission specification was
    not adequately defined in the polishing spec, leading to ITM substrate lens terms that were larger than intended (in some cases)

  • Since the Caltech metrology of the 3rd IFO COC would not be completed by the end of the COC fabrication acceptance review (but will be completed by the end of March 2015), create a punch-list of the outstanding metrology tasks (and update as appropriate)
  • The review team received an email from Gari B on March 4, asserting that all the actions had been completed:

    Dear Review Committee,
    Following is a list of actions that I took at our last meeting, February 3rd.  I have completed each of these items and include the relevant links below.  If there are other items that you believe I need to address please let me know.  - Gari

    Update Acceptance Document
    Update Final Design Document
    Update Design Requirements Document
    Create a Waiver document for each waiver, for each optic
    Link all Waiver documents to acceptance and test documents: follow any link from
    Upload MetroPro application files in the DCC
    Upload RTS labview software in the DCC
    Provide a characterization punch-list of required 3rd IFO measurements: under “other files” at
    Update the ITM polish specification to clarify the transmission requirements - 
    n.b. this is a reference document, and is not released.
    Update the 3rd IFO storage procedure to explicitly exclude First Contact (this item was taken after inquiry from Matt Heintze)

    Note on later revisions to the above:
    -- the punch-list was moved to its own document: E1500171
    -- a new file card was created that lists all the acceptance summaries: E1500170

    Additional notes:

    - There are two QA documents for the ETM and ITM coatings: Q1400001 & Q1400002. These are documents that summarize how each of the coating specifications were verified. These documents are not complete at this time, but the review chair (PF) decided that they were not required for COC fabrication acceptance. They are 'nice to have', and will be completed in due course, but the information can be found in other documents.

    - In a followup meeting between O'Reilly, Billingsley, Fritschel and Coyne the COC Final Design Review was discussed. It was pointed out that in the documented COC response to the FDR committee questions, L080133, there are a number of questions that do not have answers. This makes it difficult to know at this point if or how these questions were addressed (they may have been verbally answered at the review meeting, e.g.). Nonetheless, looking through these questions now, none of them stand out as being particularly significant.*

    *Perhaps with one exception: There is an unanswered question regarding the tolerable level of surface charge on an optic (1.5.1). Obviously we now know this is a thorny issue, and it is not easy to answer this question -- or to solve the problem. However, one 'mistake' we can point to is the initial failure (now corrected) to use an electro-meter of adequate sensitivity during the in-situ charge neutralization process (i.e., top-gun de-ionizing).

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