Star-fst-l mailing list

[Gerard Visser <gvisser AT indiana.edu>]

hi Mike,
        Let me try to answer in below  -->
        - Gerard

On 7/2/2019 2:19 PM, Capotosto, Michael (CONTR) wrote:
> Gerard,
>
> Cable size should not be an issue, as the custom cable will almost certainly 
> be smaller in diameter than three separate shielded cables.

That is for sure true the custom cable will be much smaller than those test 
cable assemblies made as a composite of three standard cables.

On the other hand though the test cable assembly would _never_ fit in the real 
installation! I think it is _not_ useful as a guide to how small is small 
enough. Better ask Rahul how small is small enough.

> As far as requirements go, it is my understanding that the cables should be 
> the same size

just same length, you mean

> as the test stand cables, coming in at 8' long +/- 1". Assuming we follow the 
> quote from the IST cables: The cable will have 16 pairs of 28AWG solid 2 conductor 
> cabled together, at a minimum of 16 twists per foot. The cable will also have 4 
> individual conductors, size 22AWG stranded (7/30). The cable will be shielded with 
> an aluminum/mylar tape, with a 25% minimum overlap, and a 22AWG stranded (7/30) 
> drain wire. Is this correct? Are there any preferences for pair colors and outer 
> jacket color?

I think for the wire colors, unique identification using solid colors is what we 
want, i.e. like in the IST cable or of course any similar scheme. We don't 
actually care at all about wire colors once the cable is assembled.

As far as jacket color, well we were told we could have any solid color at equal 
cost. Purple was nice, it is unique and says "special cable / be careful", and 
it looks nice. But it could be white, clear, anything really. (Well, probably 
better not orange.)

> Do you know if FEP was a requirement for this cable? When assembling the 
> T-Boards we had issues with the jacket beginning to melt, shrinking back, or 
> splitting - would we be able to switch to an insulation with a higher melting 
> point such as Teflon/PTFE?

I don't think you'll have trouble with melting FEP. (Also the test cables were 
not FEP, I think?)

I chose FEP for small size (it is fine to have a few mil FEP insulation, not so 
easy to do that with other materials), toughness, slipperiness, and of course 
inherent flame retardance.

The insulation on signal wires "ought" to have low dielectric loss (FEP, PTFE, 
polyethylene, or polypropylene) for best signal quality. But these cables are 
not too long, it's not a crucial point.

> Zhenyu,
> Does the 48 cable count include spares? If not, how many spares do you need?
>
> Thanks,
> Mike Capotosto
>
>
> -----Original Message-----
> From: Gerard Visser <gvisser AT indiana.edu>
> Sent: Tuesday, July 02, 2019 12:03 PM
> To: Capotosto, Michael (CONTR) <capotosto AT bnl.gov>
> Cc: star-fst-l AT lists.bnl.gov
> Subject: Re: [Star-fst-l] Cost Estimate for Production FST Inner Signal 
> Cables // Fwd: Re: integration of sTGC and Si
>
> Hi Zhenyu, Mike,
>         I send here below the info on the *IST* inner cable. Also the third 
> attachment here (not part of the forwarded message below but following a few 
> days later) was a refreshed quote for that.
>         For *FST*, I think we will revise slightly (fewer pairs)... Also if 
> necessary I think the power wires could be reduced from 22 AWG to 24 AWG as 
> the current will be 2/3 that of IST and the length also less than IST. But 
> someone should make some estimation of voltage drop. Of course 22 AWG is 
> better if the diameter is OK.
>         If I remember right, BNL purchased from Meunier for one of our past 
> projects, and they have good pricing, so when you contact Alpha for the new cable 
> design & quote you may want to suggest procurement through Meunier, unless 
> BNL can buy direct from Alpha of course.
>         Sincerely,
>
>                 Gerard
>
>
> On 7/2/2019 9:57 AM, Zhenyu Ye wrote:
>   > Hi Mike,
>   >
>   > Can you please make a cost estimate for the actual FST inner signal 
> cables, based on the work you have done for the FST test cables? We will need 48 
> of actual cables. The cost should include the cable itself (Gerard had a quote 
> for it. Gerard, can you please share it with Mike), connectors, and external 
> assembly work for the cable+T-board.
>   >
>   > Thanks,
>   > Zhenyu