Technical Specifications for the Cathode Strip Panels
Nelson led the discussion for the specification document for the Cathode Strip Chamber Panels.
The  DRAFT of the document has been distributed by Nelson. The final Version will appear on these pages.  Many suggestion were provided to Nelson, and he will include them in the next draft which will be sent out once Dave Eartly inputs comments from Plascore.  The following represents the major points and action items that were discussed.
 
 

• Section 1.0
• This is the general introduction. The major comment was that we need to add verbage  requiring PLASCORE to explicitly follow our technical spec. and notifiy Fermilab before any change in the assembly,  fabrication procedure, or manufacturing process is undertaken to avoid the possibility of any  "mid production" failure.

• Section 2.0
• This section deals with the FR4 material provided by GE (through Fermilab). We presently have 1000 sheets at FNAL, out of which 8 have shown thickness ranging from 0.0565'' to 0.0600'' (range of 0.0035'', i.e. +/- 2 mils). This is much better than our specs (+/- 5 mils).
• Action Item:     Inspection at IB4 will measure more samples  (~40 sheets, 10 out of each of 4 boxes) to check for dimensional consistency and provide confidence on the GE QC program.
• Section 3.0
• This section deals with the "Cell Core Material".  According to industry standards, polycarbonate can be "Machining Grade",  "Window Grade" or "Glass Filled". It was generally agreed that we would like to avoid the glass filling, to prevent the Axxion tooling from being worn out too quickly. However nobody knew the real composition of the poly carbonate proposed by PLASCORE.
• Action Item:    Ron and Dave will contact PLASCORE and try to determine the composition of the polycarbonate.
• Nelson put down some minimum values for the compressive and plate shear strength. According to Andry K. the values are too low with respect to the extrapolation from previous experience. However nobody knew what we need based on first principles (i.e. what we need in order to get good panels at the end).
• Action Item:    Dave and Andry will contact each other and determine the right values for these two parameters.
• Section 4.0
• This is the skinniest section in the document given the proprietary nature of the glue and our ignorance on its components. The specs provided by PLASCORE (Mil-A-25463 Type 1) were not found by our in-house material expert (Jay Hoffmann).
• Action Item:    Ron and Dave will contact PLASCORE to get a copy of the epoxy  specs. they will use in our panels.
• According to Jay, the risks to which we are exposed are the following:
• Improper component mixing so that all components do not cure properly.
• Epoxy out gassing. Jay presented some plots showing that for cured epoxy this is not a problem.
• Action Item:     Giorgio will try to quantify a limit for the epoxy out gassing.
• Epoxy degradation with radiation. Yuri stated that some measurements done at PNPI showed this not to be a problem on the samples tested. He will get a copy of the report.
• We concluded that if we cannot get specifications from PLASCORE then we will have to include some performance specifications that can be evaluated on some sample basis.
• Section 5.0
• No comment
• Section 6.0
• On the specification for the "Dents",  PLASCORE suggested that we accepted dents of up to +/- 10 mils. This, of course, would affect the Gerber cutter (which cuts only 10 mils deep). We will propose back  a +/-5 mils spec.
• We decided to remove the scratch depth requirement  (nobody knew of an easy way to measure a 0.5 mils deep scratch). We will require that no copper interruption (cut through) be present. The "visual" requirement was also eliminated as being unnecessary.
• For the tensile strength and peel strength, we will have to specify by which method the measurements are done, in case we want this to be a QA/QC test performed by PLASCORE. Nobody knew which peel and tensile strength we need starting from first principles. It was agreed that we would call GOOD the panels we have at Fermilab, measure their strengths and get an idea on the parameter values.
• Action Item:   Jay will measure some samples from the panels we presently have and determine the peel and tensile strengths.
• Nelson proposed a flatness test that was considered simple enough as a possible QA/QC test. Again we don't know which kind of variations (and which information) we can get from such a test.
• Action Item:    IB4 (Bill Pritchard) will make some flatness tests on the approx. 15 panels presently at FNAL.
• Section 7.0
• Minor changes
• Section 8.0
• This is were everything stopped. We were not able to decide what QA/QC steps will be done at PLASCORE, and which ones will be done at FNAL. The only thing that PLASCORE will measure for sure will be the core thickness, since the core  is available as a stand-alone  unit only to them during the panel production.
• Dave will receive a FAX from PLASCORE  hopefully with  their proposal for the QA/QC steps they can do at the production facility. It was agreed to wait for that message, and reconvene later this week to finalize our proposal.  In order to be able to more fully understand the QA/QC capability at PLASCORE, a delegation from FNAL will visit their facility to make sure they have adequate  manufacturing processes and QA procedures.
• Section 9.0
• We spent some time discussing the dimensions of the packaging and shipping boxes for the panels. Clearly they must be optimized both for production accessibility and storing.  Oleg suggested that 15 panels/box would be fine.
• Action Item:    Dave and Ron will contact PLASCORE to investigate the crating issue, since it affects the price of the finished product.  We need to know qty per box and stack height of boxes possible.