Minutes of the Tracker Technical Meeting
May 2, 2001
Erik reported that Hytec is studying the issue of incomplete densification of the Allcomp CC pieces recently received. They sent pieces to Allcomp for inspection. Erik will talk to Allcomp this afternoon. Hytec is preparing coupons for strength tests on the CC material, to ensure that the delivered material is strong enough. They are also preparing to do insert shear-out tests on closeout (this has always been in the plan). They plan to do the tests next week.
Hytec is working to finish the drawings of the closeout parts. Erik estimated a couple of days to get them released (this Friday at the latest). Erik will contact PCI this week about ordering core material. He will also ask about how low a cure temperature can be used for bonding the face sheets to the core, and he will ask about buying additional cores for the thick-converter tray mockups to be built in the near future in Pisa.
Sandro asked Erik also to look into the issue of outgassing of the material that Allcomp uses for impregnation of the carbon-carbon material. Erik will check this afternoon what the material is that they use.
Erik said that an error was found in Franz’s model of the tower. The thickness of the flexures was way off in the model. The result is that the 170 Hz fundamental goes down to 125 Hz. The goal was to stay above 100 Hz, so it is still okay.
Sandro said that he asked Plyform about their capabilities for expansion of honeycomb core material. They can do it but cannot guarantee good quality of the cells within about 1 cm of the edge. They need more information about machining of the core material to a precise thickness. Erik said that one must cut off the rows of damaged cells. One cuts out a piece equal to the tray size after expansion.
Sandro is also looking into the tungsten alloy. It is 95% tungsten. The vendor will specify the tolerance and surface roughness tomorrow. He will also find out more about the precise composition.
Robert reported on the status of the ASICs. The full front-end design was submitted to MOSIS (Agilent 0.5um process) for prototype fabrication (25 chips) on Monday, and the controller chip will be submitted the following week (to the TSMC 0.25um process).
SLAC will modify the MCM layout to make a mini-MCM, with just 6 front-end chips (enough for one ladder of detectors). It will be used for the initial system testing of the electronics. Probably one such system can be made for Pisa, too, if desired. ASIC production for the EM will take place after the testing of the initial prototype run of 25 chips and hopefully will yield a large sample of chips before the end of this calendar year.