Re: CDC phase shifts

["Curtis A. Meyer" <cmeyer@ernest.phys.cmu.edu>]

Hi Beni -

   the holes through the endplates are smaller than the straw ID. They
are the size of the inner donut piece. The design requires that the
straws (OD) just touch in a given layer. I suspect that the small numbers
that you are seeing are the results of measurements we did on the physical
OD of the straws.

   during construction, a donut is glued into each straw. This is then placed
inside the chamber volume and the inner part of the donut goes through
each endplate and into the hole in the donut. This is all then glued in place.

    - Curtis
On Fri July 11 2008, Beni Zihlmann wrote:
> Hi David,
> attached is the xml geometry file for the CDC with your proposed shifts
> implemented for the axial layers.
> While comparing the numbers for the radius of the layers given in the 
> CDC report (table 1 page 6)
> to the once implemented in the geometry file I find that all numbers are 
> different. Not much but
> they are definitely not the same anywhere. The differences are between 
> 0.024 and 0.133 mm.
> My question to Curtis here is how will the CDC be built? Will there be 
> two end-plates with
> holes in it and the tubes put into them? I have a hard time imagining 
> this because the differences between
> some of the layers is very small so that there is hardly any material 
> left between two  layers or even
> worse between two neighbouring straws in the same layer.
> 
> cheers,
> Beni
> 



-- 
Professor Curtis A. Meyer        Department of Physics
Phone:  (412) 268-2745          Carnegie Mellon University
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