[Halld-tracking-hw] CDC Straw Tubes

[Tim Whitlatch]

Thanks Curtis. This means that the transparency (lines along the tape 
direction) is not a concern?

Tim

Curtis A. Meyer wrote:
> Hi Tim -
>
>    as far as we know the old kapton straws have held up. We were just 
> concerned that
> with all the scratches, a small amount of damage to the straw could 
> leave some section
> of the straw floating "electrically". Optimally, we would like to 
> achieve what Lumina
> did with the first straw sample that they sent us. That may not be 
> possible, but reducing the
> amount scratches woul be very good.
>
>    Quantitatively, it is harder to call. I am concerned that in some 
> of the straws, the scrathed
> area will "float". While it is good that it is confined to about 25% 
> of the surface area, I would
> like to see that reduced by about a factor of two (at least).
>
>       -- curtis
> On 5/18/10 11:59 AM, Tim Whitlatch wrote:
>> 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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