BLTWG Meeting 11/9/2007

• Time: 8:00 EST
• Place: phone
• Present: Aschenauer, Jones, Klein, Smith, Whitlatch, Yang

This special meeting was devoted to discussion of the Statement of Work and the GlueX Tagger Specification documents being put together for the 100% tagger engineering design bid package. The following decisions were made, and names assigned to each task.

GlueX Tagger Specification

1. Change the statement of work to require only one design for the dipole yokes made of single large blocks of iron. The second option with multiple iron sheets bolted together will be dropped. -Klein
2. It is too much to provide both the Glasgow and the IHEP 35% drawings to the design firm as a starting point. They are not the same, and only we can tell which aspects of each are the correct ones. Only the IHEP drawings will be provided. The Glasgow drawings will remain an important source of information for us to use during our review of stage 1. -Klein, Yang
3. What we will provide should be collected into a single comprehensive list in the SOW. Similarly for the deliverables at each stage of the contract. The information is there in different places already, but should be collected and summarized in these lists. -Klein
4. Remove from the SOW explicit mention of the hodoscope counter supports or the need for the strongback to support them. This interface will be detailed in the focal plane part of the interface drawings. -Klein
5. All of the revisions entailed in the statement of work for stage 1 should be collected into a numbered list and appended as an addendum to the SOW. This includes the changes to a single iron block yoke design. -Klein
6. A schedule should be stated in the SOW that gives the number of weeks for each stage to be completed, for the reviews to be returned and, in the case of approval, for the granting of payment. -Whitlatch

GlueX Tagger Specification

1. New drawings should be produced that define the interfaces for the vacuum system, including the electron beam entrance and exit regions, the photon beam exit, and the focal plane interface. -Whitlatch
2. The drawings produced by Glasgow showing the alignment fixtures in the pole shoes and the alignment procedure during assembly should be added to the IHEP 35% drawing set as input to the 65% design. In doing so, we must check that there are no dimensions or details in the drawings that seem to contradict what the 35% design shows for the pole pieces, vacuum box, etc. -Whitlatch
3. All of the numbers for dimensions and tolerances should be collected together and shown in a single table. -Klein
4. Make sure there is a tolerance on the compression of the vacuum o-ring all around the pole shoes. Check that the alignment tolerance numbers in the specification are sufficient to guarantee this. -Yang

Additional notes by Tim Whitlatch

1. When the magnet is to go out for fabrication, ensure that the magnetic data of the actual material being used is submitted to Yang for analysis to ensure the fields are still within spec.
2. At the 65% level, the actual design geometry is reviewed and any changes need to be re-evaluated by Yang to ensure the magnetic field is still within spec.
3. We need to require a complete field mapping after fabrication to compare with spec.
4. We may need an additional power supply to fine tune the current powering the magnets to give some adjustability since the two magnets must maintain a geometrical relationship to fit the vacuum chamber.
5. We need to specify that all hardware is non-magnetic (maybe specify a maximum magnetic permeability for SS)
6. Require a finite element analysis for the vacuum chamber.
7. The drawings need to specify torques on bolts to ensure the proper preload so the bolts are not overloaded or stretched thus changing positions of components.
8. Keep material at downstream end of chamber to a minimum (is this number defined?)
9. Need to specify alignment pins.

Some of these need further discussion as to what is already in the specs and SOW