Re: Kapton aluminized

[Elliott Wolin <wolin@jlab.org>]

Hi,

Way back in the SSC days, when I designed similar chambers for the GEM 
central detector, we were planning on using Cu or Au coatings instead of 
Al for our cathode planes.  I recall we found lots of pitting and 
erosion on the Al coating after running the chambers for a while.  
Unfortunately I don't remember the details, as this was in 1992.

				Sincerely,
					Elliott
 

================================================================================


 Those raised in a morally relative or neutral environment will hold
		    no truths to be self-evident.
				   

Elliott Wolin
Staff Physicist, Jefferson Lab
12000 Jefferson Ave
Suite 8 MS 12A1
Newport News, VA 23606
757-269-7365

================================================================================



Eugene Chudakov wrote:
> Hi Curtis,
>
> I heard (long ago) from CERN chamber experts that aluminum coating on 
> films
> tends to develop cracks which effectively insulate some
> areas from the rest. Naively, one may expect that a 5um thick layer 
> should
> be stronger than a thin one.
>
> Which thickness are you using for the prototypes?
>
> Thanks,
> Eugene
>
>
> On Fri, 6 Mar 2009, Curtis A. Meyer wrote:
>
>> Hi Tim -
>>
>>    what we observed with the 1mu is that there are scratches on it. I 
>> was
>> hoping that by going to a thicker layer, we could reduce the the chance
>> of that occuring. As long as the finish is "clean", I am ok with 1 
>> mu, I was
>> just hoping to reduce the chance of problems.
>>
>>   Curtis
>> On Fri March 6 2009, you wrote:
>>> Hi Curtis,
>>>
>>> I believe you currently have 1 micron thick aluminum which was vapor
>>> deposited on 3 mil Kapton. You had mentioned that you wanted to go to 2
>>> micron aluminum. I spoke with Sheldahl and they said the thickest they
>>> could do was 1 micron (and that is pushing it). Is the 2 micron really
>>> required? I will check availability with other vendors.
>>>
>>> Cheers,
>>>
>>>        Tim
>>>
>>>
>>
>>
>>
>> -- 
>> Professor Curtis A. Meyer        Department of Physics
>> Phone:  (412) 268-2745          Carnegie Mellon University
>> Fax:    (412) 681-0648            Pittsburgh PA 15213-3890
>> cmeyer@ernest.phys.cmu.edu  http://www.curtismeyer.com/
>>
>