spine team meeting #1 November 15, 2000 CERN present: H-G Moser, A. Clark, H. Becker, R. Thompson, S. Snow, J. Ludwig, U. Hirt 1) scope of the team: the team should work mainly as "procurement" team dealing with: procurement of components, assembly, costs, QA. Design variation like straight split/crooked split, TPG width should preferentially be discussed in the thermal performance team. Clearly, design variation which have an impact on assembly and price need to be discussed in this team. 2) composition of the team: All institutes which have responsibilities for module components should be represented in the team, so it was agreed to invite representatives from NIKHEF, Valencia and Melbourne for future meetings. 3) 60 spines pre-series results: 30 spines are ready and shipped to CERN. (Added later: Arrived Monday, November 20). One problem occurred during production: the thickness tolerances of the thinned pieces were wrongly understood (+0.025 - 0.000 mm instead of +0.000 - 0.025 mm). Therefore the gap for the glue was too small, resulting in spines out of tolerances. NIITAP agreed to re-work the pieces. Documentation on measured thickness exists. The spines will be checked at MPI and a bias connection will be printed on them. The second batch of 30 will be ready end of November. Jens Ludwig will forward the agreed distribution scheme. H.-G. Moser gave a short report on an INTAS project to improve TPG thermal conductivity. In short: high pressure annealed TPG samples were made, which have in principle very good thermal conductivity (> 2000 W/mK). However, there is a larger spread from sample to sample and the material is mechanically weaker (microcracks). Work will continue. 4) outstanding issues: bias contact, TPG openings drawings to be produced by H-GM 5) costing: The present spine price of the pre-series is ca. 130 US$. The change of the TPG width from 12 mm to 23 mm will result in a higher price: the TPG raw material price will double from 20 US$ to 40 US$. The costs of the surface treatment are likely to increase, too (presently ca. 14 US$). A part of the latter could be recovered by relaxing the specifications (presently +- 25 microns on the thickness). Further cost increases are due to the profiling of the AlN. The present price is 11 US$ per set is for a 12 mm slot. The costs should scale with the width. In addition the yield may be reduced. The price might therefor go up to 25-30 US$ Design variations which avoid this large profiling should be seriously considered. A. Clark presented some work by U. Hirt proposing to fix the rib's using small inserts and steps (like improved butt joints). It was agreed that A. Clark will provide drawings of this design study and H-G Moser will discuss this with IHEP. A cost estimate should be made and prototypes produced (At IHEP and/or MPI). If successful the design work (drawings) will be transfered to Liverpool. Furthermore A. Clark will check if ribs can be made from carbon fiber instead of AlN and get a price estimate. In parallel Liverpool should complete the update of the standard design (profiled AlN). The question whether the AlN at the detector/fan in should better be replaced by quartz was discussed. No consensus was reached and S. Snow, HG Moser and H. Becker were asked to compile and present existing information on this question next time. H-G Moser will also get a cost estimate from other sources of TPG (Advanced Ceramics) 6) design variations and improvements list of proposed and agreed changes: proposed agreed drawing exists 1 23 mm TPG for all yes no 2 wider cutout at ? no far end cooling block 3 bias line yes no 4 but joints - no 5 other material - no 6 straight split - no 6a glass piece for - yes straight split alignment 4 and 5 are already covered. 2 seems to be agreed. 6 and 6a will be covered by the thermal/mechanical performance team 7) QA measures: - survey of components - thermal measurements - HV test (sparks) - AlN insulation test need to prepare the database (contact D. Ferrere). It was discussed whether thermal cycling is needed. No conclusion was reached, but nobody had a strong opinion: if it turns out to be necessary it can be done. 8) Procurement plans There is an urgent need to produce 23 mm spines of the (close to) final design for thermal/mechanical measurements and modules prototypes. Production of 30 spines should be prepared at IHEP. Because of the delay of W12 detectors only middle and outers need to be produced. The actual design will be decided in the next meeting (wait for decisions on straight split and butt joint discussion and tests) 9) Next Meeting: It should be tried to align the spine team meeting with the thermal performance team. Next meeting should be arranged after the SCT week. H-G. Moser proposed another meeting January 25/26 at MPI (There will be a meeting at MPI with people from IHEP, Atomgraph and NIITAP on the INTAS project). Action list of meeting #1: 1) H-G Moser to invite representatives from NIKHEF, Valencia, Melbourne 2) Jens Ludwig will forward the agreed distribution scheme. 3) A. Clark ask engineers for relaxed specifications on thickness variations 4) H-G Moser to get a cost estimate from other sources of TPG (Advanced Ceramics) 5) S. Snow, HG Moser and H. Becker were asked to compile and present existing information on replacement of AlN by quartz next time. 6) A. Clark to provide drawings of "small insert ribs" 7) H-G Moser to discuss this with IHEP. A cost estimate should be made and prototypes produced (At IHEP and/or MPI). 8) A. Clark to check if ribs can be made from carbon fiber instead of AlN and get a price estimate. 9) H.-G. Moser and S. Snow to organize next meeting (jointly with thermal performance team)