Minutes of feedthrough meeting of 5 September, 2000.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Present: GV, Pof, MLenc, AD, TH, RL, MLef, RKK, MGF

*) Milestones:

	- 300 Vacuum Cables arrived on 31 August.  Testing
	  is underway.

	- Thermal tests on FT0 were completed last week.  Terry's
	  and Paul's summary report is included here.

		With good vacuum (~10E-08mbar) in the bellows and
		all six resistors powered for a total of 15 watts,
		the coldest region in the pin carrier was at 19C
		and the hottest (on a resistor) was 29C. The plate
		centre temperature was 24C.

		As above but with two adjacent resistors not
		powered (the 15 watts was on the other four
		resistors). The coldest region was 20C (nearer the
		unpowered resistors), the hottest resistor was at
		30C and the plate centre temperature was 26C.

		With atmospheric pressure in the bellows and all
		six resistors powered for a total of  77 watts,
		the coldest region was 31C, the hottest resistor
		49C and the plate centre was at 36C.

		As above with four resistors providing the 77
		watts, the coldest region (nearer the unpowered
		resistors) was at 27C, the hottest resistor was at
		60C and the plate centre was at 46C.

		For the latter two test the heater power could
		have been lower, perhaps 60 watts, to reduce all
		the temperatures by about 10C.  The lower heat
		loss in this last series of tests was probably due
		to the closer fitting and slightly thicker thermal
		insulation used in this first  production
		feedthrough.

*) No further welding will be performed until the TIS welding issue
   is resolved.  Terry will send Desirelli a note this week as a
   reminder that we need to be informed of what `problems' remain with
   the weld samples.  Terry will also inform Pierre Pailler of the
   situation.

*) Southern Cross is expected to finish the heater plate / bellows
   braces order within the next 2 - 3 weeks.  

*) It has been (tentatively) decided to use 75 Ohm resistors for
   the heater plates, rather than the 50 Ohm resistors originally
   planned.  Mark has designed a circuit board to hold the fuses
   which is to be attached directly to the heater plate.

*) Terry, Roy, Mark, and Margret will be at the September LARG
   week.  Terry and Mark will discuss the heater design and
   test results, and should also make clear that the heaters 
   must be installed *after* the feedthroughs are installed.
   Clarification will also be sought by Terry on how the 
   heaters will be controlled in the event of a failure,
   given that the present design stipulates that each power
   supply will be supplying the power for one half each of two
   adjacent feedthroughs.  Margret will present a feedthrough 
   construction status report.  Margret will also press Allain 
   Gonidec for specific information (make/model) on the leak
   checker that will be made available for our use at CERN so
   that we can design and build the interconnecting plumbing.
   She will also ask Allain if a Tektronix 2440 digital scope,
   with a GPIB interface, might be available for our use for
   electrical tests.

*) Regarding Horst Oberlac's request that UVIC order the HEC
   LV warm cables, Richard will request information from David 
   Lissauer on the EndCap warm cable design.  Specifically, we
   need information on the cable length and the connector types.
   Among other considerations, are the connectors compatible with
   with wire gauges that will be required for the LV cables?

*) After some discussion, it was decided to have the dye penetrant
   tests done on the feedthroughs *after* the cold tests, as 
   originally planned.  The weld areas of the feedthroughs probably
   remain too warm for too long after the weld is performed to have
   the tests done on the same day.  It is also (hopefully) unlikely
   that the dye penetrant tests will result in failure, so the
   risk of having to redo a cold test after a reweld is low.
   The dye penetrant test on FT0 should be done ASAP, once it's
   removed from the cold station.

*) The September LARG week is the last that Terry will attend, so
   Paul Birney should consider attending the December LARG week.

Agenda for next week:
^^^^^^^^^^^^^^^^^^^^^
- Milestones
- Documentation status
- Vacuum Cable testing status and plans
- AOB