September 30, 2009 CDC Meeting

Ground HV Card Through Standoff

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