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Re: CDC Interconnect Concepts - EDAC
Hi Fernando -
There is a talk at the user's meeting at 9:00am which I need to
be at. There will also be a GlueX conference call at 11:00am.
I guess that this meas that in the afternoon is the best time.
If you can find a room, that would be great. I am not very good
at reserving things remotely.
Curtis
On Thu June 12 2008, Fernando J. Barbosa wrote:
> Hi Curtis,
>
> When is it a good time to meet/have a conference call next week? Can you
> reserve a room here or do you want me to reserve one? Let us know.
>
> Regards,
> Fernando
>
>
>
>
> Yves Van Haarlem wrote:
> > Hi All,
> >
> > About the phone conference. Curtis is at JLab next week and he can
> > meet all Wednesday, Gerard and me could phone in. So what about having
> > a meeting next week Wednesday at 1pm (first iteration)?
> >
> > Here are some comments on comments:
> >
> >>>> In particular, I find the cable length from the straws to the
> >>>> preamp card of
> >>>> about 8" to be excessive and with limited shielding, from outside
> >>>> and between
> >>>> channels.
> >>
> >> Me too. This is an issue not of ease of construction, but of
> >> performance (EMI sensitivity). Yves, maybe it is in fact impossible
> >> to do better, but it should at least be recognized as risky and
> >> cannot be lightly dismissed just because "it only has to be connected
> >> once." This is _not_ Fernando's main point, I believe.
> >
> > The 8" length is an absolute maximum - we are reviewing an option from
> > Slava/Tim that would reduce that length significantly (we could go
> > into this in the phone conference).
> >
> >
> >> But, on the other hand, what part number are you looking at
> >> specifically,
> > 341-026-500-202
> >> Yves. I just now checked EDAC website, for instance this connector
> >> looks fairly suitable:
> >> http://www.edac.net/downloads/306-316-356%20Series%20Spec%20Sheet.pdf
> >> It has a rating of 2545 VDC between adjacent contacts! It comes with
> >> card guides as an option. Looks good to me.
> >
> > Gerard, when you were here you recommended the 341 series. Also,
> > before I ordered them I've sent a mail to the tracking list. Anyway: I
> > took a connector with a double row connectors because that was the
> > only one I could order (i preferred the single row at that time to
> > have a stronger connection with the HV board). There was only one
> > company that could deliver them (www.newark.com, delivery time was 2
> > months) and they could only deliver the 341-026-500-202. I even called
> > EDAC and the result was that our possible order was not enough (I told
> > them that we might order 200 of those connectors) to start a
> > production line (they do not have them in stock). I just did a little
> > surfing for the 306/316/356 series and see a similar problem: no
> > single row connectors with enough contacts available to be ordered
> > immediately (but it might be my surfing).
> >
> > We can look into the 306 series but for the test with the new
> > prototype we'll most likely use the 341-026-500-202 (depending on when
> > it will be build): this has implications for the HV board design to be
> > used with the new prototype.
> >
> >>>> Presently, according to Yves' drawings, the 26 contact connector
> >>>> connects 24 straws and 2 contacts are used for grounding the preamp
> >>>> carrier
> >>>> PCB to some ground point, presumably the end plate.
> >>> Maybe I did it wrong in the drawing but we do not plan to use the two
> >>> remaining contacts for grounding for the reason you mention.
> >>
> >> No, Yves, I think you do... Or at least, I think you should. The
> >> preamp ground to the end plate is as critical, more critical than the
> >> anode wires connection.
> > I completely agree about the importance of the grounding. If I
> > remember correctly, we were worried about connecting those 2 pins to
> > the ground. Instead we are still looking into connecting the HVB
> > ground to the end-plate in other ways (I believe Fernando's grounding
> > rods and Al shielding would be a way to do it). Also here we have a
> > point for the phone conference.
> >
> >
> >> A connector of 26 pins, single row, 0.156" would work well, use the
> >> two end pins for the ground and use the middle 24 for your signals.
> >> Or, perhaps better for reliability, if it fits which I imagine will
> >> not be a big problem, use a 28 pin connector, 24 signals in middle,
> >> skip one pin on each end (let it float on connector, have no/minimal
> >> contact pad on pcb, not connected), and one ground pin on each end.
> >> This will give some extra clearance against surface leakage or
> >> breakdown on the pcb board.
> > We should come to an agreement about what connector to use and find a
> > better way to order them.
> >
> > Cheers,
> > Yves
>
--
Professor Curtis A. Meyer Department of Physics
Phone: (412) 268-2745 Carnegie Mellon University
Fax: (412) 681-0648 Pittsburgh PA 15213-3890
cmeyer@ernest.phys.cmu.edu http://www.curtismeyer.com/