[Halld-tracking-hw] CDC Ground Connections

[Tim Whitlatch]

How much force do we anticipate on making these connections?10lbs? 20lbs?

Tim

Gerard Visser wrote:
> Hi Curtis,
> 	I endorse completely your comments regarding deflection and 
> reliability! There should either be more mechanical support (which could 
> serve as a ground connection, or not) or else there should be attention 
> to make an insertion/extraction tool and features in the design to 
> insert/extract the HVB without applying too much force that strains the 
> wire connections.
> 	For the wire pin to the ground sockets, for instance there is 
> http://www.mill-max.com/pdf/datasheet/pin_rec_catalog/8000-0-01-15-00-00-03-0.pdf 
> if you would be able to use a #19 or #20 wire. It is just slightly too 
> small for #18. But IMHO it should be enough - unless there is a 
> mechanical consideration about the wire diameter passing through the gas 
> seal that I don't know about.
> 	Sincerely,
>
> 		Gerard
>
>
> Curtis A. Meyer wrote:
>   
>> Hi Everyone -
>>
>>      a couple of points on the grounding connection.
>>
>>     Sometime ago, we had proposed "continuing" one of the legs that 
>> supports
>> the connectors for the HV-boards through the gas plenum to the endplate. 
>> This
>> standoff would then serve to both support the HV connector and provide a 
>> solid
>> ground connection to the end plate. The one concern is that it might not 
>> be possible
>> to place one support for each connector such that the feed through can 
>> carry through
>> to the end plate.
>>
>>     Assuming that the above is not possible (which we still feel would 
>> be the best grounding
>> and support scheme), then we are worried that there are not enough stand 
>> offs in the current endplate, there are only eight as far as we can tell 
>> in the current design.
>>
>>     We are very concerned that there are not enough standoffs to support 
>> the swiss cheese
>> plate, particularly during insertion and removal of the high-voltage 
>> cards. What we see with
>> the models that we have at CMU is that the force needed to insert and 
>> pull the card is
>> sufficient to actually compress or pull-out the plastic plates. The way 
>> the connection
>> scheme now goes. This distortion becomes a force either directly on the 
>> crimp pin,
>> or on the glue joint that seals the chamber. These have the potential to 
>> break wires
>> in the straws or break the gas seals every time a HV board is changed.  
>> It is important
>> that additional standoffs be added, either during or after manufacture 
>> of the Al endplate.
>>
>>     Finally, assuming that we adopt Fernando's connector, we need to 
>> know if there is a
>> source of the .020 male part that can be soldered to the .040 wire and 
>> is inserted in the
>> press-fit hole. The connector itself is quite slick and the 60gm force 
>> needed to engage
>> it seems fine. But the male part is equally important to this working.
>>
>>
>>      -- Curtis
>>
>>   
>>
>>     
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