Wed., Nov. 9th

Ray and I are planning to go over to the Challenger center at about 4:00 pm, to meet with Reed to finalize the issue of the detector locations.

Samad is coming by soon to talk about the power supply some more.  I emphasized to him the importance of building proper connectors to connect the power supply (and batteries) to other components.

Samad needs to get me quotes for the batteries, battery charger, and any connectors so that I can issue a requisition for them.

Also, the mechanical students need to design structures to hold the power supply INSIDE (not outside) the main electronics box, for neatness, and there should also be a little battery-holder box installed on one of the detectors (for a battery-powered detector demonstration).  Mechanicals need to coordinate with Samad on the requirements for this.

Cooling of the ambient interior temperature of the main electronics box should not be a problem, even with the power supply inside, as long as there is airflow with vents/fan.  Total system power dissipation is not all that large (20-30 W, laptop range).  Main requirement for cooling is a good heat pipe from the FPGA to the Peltier plate, to get the FPGA as close as possible to the cool end of its 0-85 C operating range.  And positioning the plate so any drips go into a tray and not onto the electronics.  Mechanicals should look into sealing all cold exposed metal parts inside a polymer/resin skin, spray-on perhaps, to reduce condensation.

Reed had to leave CLC before we arrived, but his assistant was there.  It looks like hanging the detectors below the ceiling is OK as long as they do not dangle down more than about 1' or so - ceiling height is 9'2".  Main concern is that people don't hit their heads.  Also, there are sprinkler clearances and location of above-ceiling girders to consider.  Requested blueprint for other half of room - Brian said Pascal had one half already, but it needs to be scanned and uploaded to the group blog so everyone can see it.

Brian is thinking now of arranging all boards on one plane, instead of using the blade approach.  This is probably a good idea since it will reduce the vertical profile of the enclosure.   Height of enclosure should probably be no more than 14".

Also, I discussed with Brian that the enclosure should NOT have RF shielding, since the Wi-Fi communication needs to pass through.  I don't think we're too worried about interference.  Also for educational purposes it would be nice if the electronics was visible.  We agreed that probably best is if 5 out of the 6 faces of the enclosure were transparent plexiglass (except where the exhaust fan and Peltier cooler are installed, obviously), and the other face can be metal that all the boards are bolted to (everything mounted upside-down under it).  That way, students can see all the electronics, and any indicator LEDs on the boards.