Re: Cathode Films from Sheldahl

[Gerard Visser <gvisser@indiana.edu>]

Hi Fernando,
	Also, after my earlier email I reviewed the situation for the CDC, just 
didn't bother to write back yet again. There the wire resistance is I 
think about 180 Ohm/m, and the characteristic impedance is 400 Ohm (on 
the basis of capacitance formula 2*pi*e0/ln(b/a) and the velocity=c). 
[But this is neglecting the spiral gap in the straw tube wall metal, 
another one of my "concerns".] So, one thing to say is we should look at 
it (line loss effects) for the CDC as well, but conversely one could say 
that this means it is not _really_ unworkable to have the line 
resistance 50% of the characteristic impedance. Still, I think we should 
aim to keep it under 10% for the FDC if possible, sounds like it will be.
	We can talk more after the review - let me know the meeting time if you 
find one. I have a couple of conflicts coming up next week...

	Gerard
	

Fernando J. Barbosa wrote:
> Hi Gerard,
> 
> It looks like a good plan and we should talk about it maybe next week.
> With regards to the conference call I suggested earlier, I only received
> a reply from Dan and you and Dan cannot make it on Monday morning.
> 
> I have just started some of this modeling but other projects are taking
> priority at the moment in view of the upcoming reviews. I have the
> software to perform the analysis, I think. So, send me items 3 and 4
> when available.
> 
> I think, practically speaking, that we will be limited to 2 um Cu foils
> and the resistance of the line won't be an issue. Obviously, this sets
> the practical limit for mass reduction in the detector area of the FDC.
> 
> Regards,
> Fernando