[Halld-tracking-hw] CDC Straw Tubes

[Eugene Chudakov]

I agree with Fernando and Elton.

The new Lamina straws are not acceptable. We should discuss it with Lamina. 
This transparency test is simple - they should be able to do it themselves.
I hope they will be able to reproduce the quality of their first batch 
delivered a few months ago.

Eugene

On Tue, 18 May 2010, Tim Whitlatch wrote:

> 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
>>>>>> 
>>>> 
>>>> 
>> 
>> 
>