[Halld-tracking-hw] CDC Straw Tubes

[Tim Whitlatch]

I have taken pictures against a back light of the 3 straw samples Curtis 
gave me. They can be found at;

http://www.jlab.org/Hall-D/software/wiki/index.php/CDC#Straws

I am trying to get a handle on the requirements for the straws. The 
first shows the Stone aluminized Kapton with a back light. As can be 
seen, most is transparent and the lines can be seen in the direction of 
the wrap. The 2nd is the latest Lamina aluminized mylar. There are some 
lines that are transparent and some scratches.
The 3rd is the original Lamina aluminized straw from Last fall 
(supposedly the same material as the new ones) This is completely solid 
against the back light.

What is the requirement here?
Had the kapton straws held up over the past couple of years in the 
prototype setup?
Is the original Lamina straw acceptable?
I just wish to be clear before I get with the Lamina rep on this.

Thanks,

       Tim


Curtis A. Meyer wrote:
> Hi Everyone -
>
>        we have finished going through the 252 straws that were sent to 
> us by Lumina.
> Other than the scratches that we talked about at the meeting last week, 
> the straws
> appear to be pretty good. The final numbers on the mechanical acceptance 
> are:
>
>      186/252 straws are good
>        28/252 straws were rejected because they were oval. Better 
> packing in the
>                    shipping box would probably recover all of these. 
> This would give
>                    us an acceptance rate of:
>      214/252  or 84.9%   and we would need 4120 straws to get 3500.
>
>      Of the rejected ones,  19 were rejects due to imperfections in the 
> straws,
>      wrapping, glueing, extra crud stuck to them, ..... The remaining 17 
> were
>      bowed beyond the 1/10 inch specification. This appears to be in the 
> straw
>      and not due to shipping or packing.
>
>       In order to improve the regular shipment, the box containing the 
> straws probably
>       needs to be compartmentalized so that there are fewer straws 
> pressing on each other.
>       Perhaps a wine-crate like structure that has ~ 40 straws in each 
> compartment???
>
>       The overall biggest issue that we saw was the scratches on the 
> straws. The vendor did
> not have that on the original samples that we received (a year ago).
>
>     Curtis
>
>   
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