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Re: CDC Interconnect Concepts - EDAC



Hi Yves,

It works for me. I am also CCing Tim and Slava in case they want to join.

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
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