[Halld-tracking-hw] Stand-off sketch ...

[Curtis A. Meyer]

Fernando J. Barbosa wrote:
> Hi Curtis,
>
> How do you plan to keep all these parts from rotating once installed?

--    Conducting epoxy.
>
> How do you plan to make the GND connections from the connector? Please 
> provide a sketch with details.
>
--  We either design the board with a ground connection at the two 
screws (preferred method)
     or we have a very short jumper to the standoff.

> Thanks and best regards,
> Fernando
>
> Curtis A. Meyer wrote:
>> Attached is a rough sketch showing the proposed stand-off scheme.
>> 1) A 6/32 blind threaded hole is drilled in the endplate.
>>
>> 2) A 6/32 set screw is screwed into the hole. We can use conducting
>>    epoxy to improve the connection if needed.
>>
>> 3) A 1/4 inch electrical standoff with a 6/32 tapped hole is screwed 
>> onto
>>    the set screw. There are three possible variations on this for the 
>> end
>>    in contact with the endplate.
>>    i) There is room for the 1/4 inch, nothing specicial
>>    ii) There is not quite enough room for the 1/4 inch due to the  
>> heads of
>>         the feedthrus extending 1/10" above the surface of the plate.
>>         We can order a standard 1/4 standoff that has a diameter of 
>> 188 for the
>>         last .133 inches. This comes from McMaster-Carr.
>>    iii) Or we can make in house modifications:
>>          a) we can (in house as needed) taper the end of the standof 
>> down to ~188
>>              from 250 so it will fit,
>>          b) we can (in house) as needed remove some material from the 
>> head
>>              of the feed throughs so that the 1/4 in can reach the 
>> endplate.
>>
>> 4) A .156 inch hole is drilled through the lucite plate.
>>
>> 5) A 6/32 set screw goes through the lucite plate and screws into the 
>> standoff.
>>
>> 6) Epoxy, or conducting epoxy in placed around the 6/32 set screw.
>>
>> 7) A  1/4 inch electrical standoff with blind 6/32 holes is screwed
>>
>> 8) The connector is attached to the standoff.
>>
>> We also would like to propose the standoffs that hold the HV card be 
>> on opposite
>> sides of the card, rather than both on the same side. This gives less 
>> chance that the
>> card will tilt during installation and removal.
>>
>> @===  High-voltage board
>> O          Standoff/set screw of installation/removal.
>>
>>                                   O
>>                                @=============================@
>>                                                                                                   
>> O
>>
>> Curtis, Gary and Yves
>>
>> ------------------------------------------------------------------------
>>
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-- 
Prof. Curtis A. Meyer		Department of Physics
Phone:	(412) 268-2745		Carnegie Mellon University
Fax:	(412) 681-0648		Pittsburgh PA 15213-3890 
cmeyer at ernest.phys.cmu.edu	http://www.curtismeyer.com/