June 19, 2009 CDC Meeting

Meeting Time and Place

Friday June 19 2009 at 11:00am At Jefferson Lab, the meeting will be held in room ARC 428

Connections

To connect from the outside, please use ESNET
1.) ESNET: 8542553
2.) Phone:
+1-800-377-8846 : US
+1-888-276-7715 : Canada
+1-302-709-8424 : International
then enter participant code: 39527048# (remember the "#")

Agenda

1. CDC Drawings
   1. The above drawing were shown on June 11. There was some concern that the compression fitting on the upstream endplate would be difficult to align and hold in place, and would also transfer too much force to the endplate. CMU wondered if the grooved scheme that was proposed for the main shell could be used here instead.
   2. There were some questions raised about being able to seat the swiss-cheese plate on the standoffs given the number of items that needed to align with it.
2. Curtis' List from Last Week
   1. Donut and Feed-thru specifications GlueX-doc-1284 is a start on getting this going. We need to integrate this with the straw and endplate specifications so that all parts will fit together. Notes at the end of this indicate a scheme for doing this.
   2. CDC Assembly Procedures, GlueX-doc-1280 has been updated to include the stringing of wires. This impacts the design of the crimp pin. Namely, in order to be able to force the crimp pins into the plastic insert without damaging the wire that goes through it, we think that we need to have the lip on the crimp pin.
   3. Given the above lip on the crimp pin, we think that the crimp pin length should be roughly as follows (based on the pin diagram from Medelec).
      1. 1.7 mm long swaged tip
      2. 4.0 mm to start of press-fit shoulder
      3. 6.0 mm long press fit shoulder
      4. 4.0 mm long "crimp region" after the shoulder.
   4. Straw status. It appears that only one of Tim's questions with regard to the straws was answered in the email from Lumina (having to do with the Al layer). Can we get answers to the additional questions that Tim posed?

Action Items

• 97% drawings out to vendors?
• Update on Straws from Lumina.
• Which CERN experiment used the first version of the Lumina Straws.
  • The group involved is in Italy and Beni has emailed the contact person with a question.
  • We have received a sample of the "300 Angstrom" foil from Lumina. Is it really 300 Angstrom thick?
  • Eugene reported that the resistance of the foil on the first tubes is consistent with the 30nm reported thickness.
• Status of CDC Donuts and Feed-thrus.
  • Draft specifications are in GlueX document.
  • We need to double check all of the tolerances.
• Does the magnetic field need to be mapped?

Endplate Features

I wanted to start checklist of features that we know need to be present on the end plates. I suggest that we add to this and color-code those that are done.

• Specifications on drilled holes consistent with feed-thru diameter.
• Specifications on stereo lip consistent with feed-thru head diameter.
• Markings on endplates for number "1" straw in each layer. Particularly important for stereo as the ends will not line up.
• Tapped holes for plenum standoffs.
• Tapped holes for grounding standoffs.
• Survey holes.
• Survey cut outs in upstream endplate.
• Specifications/details on 12 support rod holes.
• Specifications/details on 12 (6 in/6 out) gas line holes.
• Space at inner radius to support the lip of the support plates mounted to the mandrel.
  • The lip used on the 2m prototype is 0.15inches (we would rather have more, but this worked).
• Features to mount inner shell.
• Features to mount outer shell.