[Halld-tracking-hw] Grounding & Cabling

[Fernando J. Barbosa]

Hello everyone,

    I have checked a few of our options for grounding on the CDC. The 
grounding threaded receptacle is not in stock but is made to order with 
a 2-3 week delivery. The cost for each piece (we would need 154) is ~$8 
(I have a quote if you need it) but there is a minimum order of 1,000 
pieces - ~$8k. This seems too expensive for me but you decide.

    The alternative, my preference, is to follow Gerard's suggestion of 
a press-fit receptacle (I have attached a pdf). This can be press-fit or 
inserted with conductive epoxy into the endplate. The final diameter of 
this plus the pin on the end of the grounding wire should be ~ 0.1". 
This part is available from stock, costs $0.625 and there may be a 
minimum order of 500 pieces. The cost should be ~$300.

    There is also the alternative suggested by Curtis with threaded 
studs (perhaps a threaded spacer) but this would require that ground 
wires from several preamp connectors be attached to one of these studs 
(haw many can be fit?), where the path to the endplate is not as direct 
nor short.

    For cabling the straw connections, there are several options for 
stripping the cable. RG316 was chosen by Gary because it is Teflon and 
stands better to the heat from soldering the braid to the small PCB 
under the preamp connector. Teflon is hard to gas seal and strip. I 
think RG174 could work if Gary could make a clamp/clamshell with 
half-holes (if that's the right word) that secures the 12 or 24 cables 
and serves as a heat shield and cable-alignment jig.

    I have looked into stripping tools and I strongly recommend a 
machine that does this: stripping is fast (jacket, braid, etc) and in 
one operation, reproducible and places less stress on the cables. The 
strip lengths are adjustable for each of the steps in the cable (jacket, 
braid, etc). Some manufacturers are: www.schleuniger.com, 
www.carpentermfg.com and http://www.coasteltools.com/prod_715.htm. I 
recommend checking with Coastel. They can custom make the cutting heads 
for the strip lengths and cable you use and using their hand-held coax 
stripper. On the other hand, some table top coax strippers are small 
enough that they can be placed on a movable table/jig and bring it to 
height and location of the cables to be stripped.

Best regards,
Fernando


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