[Halld-tracking-hw] CDC Straw Tubes

[Tim Whitlatch]

I am not referring to the gaps between tape windings, I am talking about 
the lines (prominent on the kapton and somewhat on the new Lamina) that 
run parallel to the gap

Tim

Curtis A. Meyer wrote:
> I believe that we were within specifications on the line (the gap 
> between wraps).
> It is only the scratches that worry me --  curtis
>
>
> On 5/18/10 12:34 PM, Tim Whitlatch wrote:
>> 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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