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

[Christopher Keith]

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
>
>
> _______________________________________________
> Frost mailing list
> Frost at jlab.org
> https://mailman.jlab.org/mailman/listinfo/frost

-- 
_____________________________________________________________
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
_____________________________________________________________

-------------- next part --------------
An HTML attachment was scrubbed...
URL: https://mailman.jlab.org/pipermail/frost/attachments/20130314/261b7efd/attachment.html