[Frost] The hydrogen contamination pf the carbon target in g9a data

[Christopher Keith]

Hi Sung,
I don't know why there is a downstream, CH2 shoulder in the g9a 
spectrum, but not in the g9b.  The simplest answer is that we used more 
super-insulation in g9a.  I do not think this is the case, but I will 
check our notes when I can.

Chris

On 3/14/13 11:01 AM, Park, Sungkyun wrote:
>
> Hi Keith,
>
> Thank about your comment. I will update your comment in my 
> presentation. However, If the shoulder of the CH2 target  in g9a data 
> is from the super-insulation on the 20K shield, why we can not see any 
> shoulder in CH2 vertex distribution of g9b data or additional peak 
> near the CH2 peak?
>
> Sung
> ------------------------------------------------------------------------
> *From:* frost-bounces at jlab.org [frost-bounces at jlab.org] on behalf of 
> Christopher Keith [ckeith at jlab.org]
> *Sent:* Thursday, March 14, 2013 10:20 AM
> *To:* frost at jlab.org
> *Subject:* Re: [Frost] The hydrogen contamination pf the carbon target 
> in g9a data
>
> Hi Sungkyun,
> The 12.5 cm peak that you see in the g9b spectrum is probably due to 
> superinsulation (SI) on the downstream end of the 1K shield. In g9a, a 
> similar quantity of SI was used, but it was pressed against the carbon 
> target and is probably visible as the slight shoulder at 7cm on the 
> carbon peak.
>
> In g9a there is a similar shoulder on the CH2 at 17cm, and this may 
> also be due to SI on the 20K shield.  I don't see the corresponding 
> shoulder in the g9b spectra, though.  I'll look at our notes.
>
> Chris Keith
>
> On 3/13/13 5:38 PM, Park, Sungkyun wrote:
>> Hi Eugene,
>>
>> I made the presentation using the Keith pictures to have better 
>> understanding about the hydrogen contamination. I think this can be 
>> the good reference to discuss our current issue "hydrogen 
>> contamination in the carbon target"
>>
>> hadron.physics.fsu.edu/~skpark/document/FROSTM_Mar1313.pdf 
>> <http://hadron.physics.fsu.edu/%7Eskpark/document/FROSTM_Mar1313.pdf>
>>
>>  In slide 1, the carbon and CH2 target in g9a vertex have shoulders 
>> downstream and there are new peak between carbon and CH2 target in 
>> g9b vertex. Our current conclusion may be the peak between the carbon 
>> and CH2 target is from the super-insulation and this super-insulation 
>> make the shoulder part in the carbon data. However, there is no 
>> description about the should of the CH2 target.
>>
>> I think that (E)outer vacuum can, (D)20K heat shield, and (B)1K heat 
>> shield in Figure 3.6 in slide 1 are used in g9a and g9b together. I 
>> think the vertex difference between theg9a and g9b is from the 
>> holding magnet with the different size.
>> If so, we can not find any reason for the CH2 shoulder part  because 
>> the CH2 target is installed out the 20K heat shield.
>>
>> Can I update this presentation on our FROST meeting web-page?
>>
>> Sung
>> Florida State University
>>
>>
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>
> -- 
> _____________________________________________________________
> Christopher D. Keith
> Jefferson Lab               email:ckeith at jlab.org
> 12000 Jefferson Ave.        ph: 757-269-5878
> Postal Suite 6              fax: 757-269-5235
> Newport News, VA 23606
> _____________________________________________________________

-- 
_____________________________________________________________
Christopher D. Keith
Jefferson Lab               email: ckeith at jlab.org
12000 Jefferson Ave.        ph: 757-269-5878
Postal Suite 6              fax: 757-269-5235
Newport News, VA 23606
_____________________________________________________________

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