[Frost] FROST z-Vertex Distributions

[Eugene Pasyuk]

I think we considered this and concluded against it. One of the reasons was that the contamination seemed to be on the downstream side of carbon, while endcap foil is on the upstream side. Also the contamination seems to be too large for the thickness of the foil. However looking at your g9b plot I see that the effect is not very small. 

-Eugene 

> From: "Volker Crede" <crede at fsu.edu>
> To: "Eugene Pasyuk" <pasyuk at jlab.org>
> Cc: "frost" <frost at jlab.org>, "priyashree roy" <roy.priyashree at gmail.com>
> Sent: Wednesday, March 16, 2016 12:54:55 PM
> Subject: Re: [Frost] FROST z-Vertex Distributions

> Hi Eugene,
> This is an interesting thought about the hydrogen contamination, indeed. Perhaps
> you hit the nail on the head ;-)

> - Volker

> On Mar 16, 2016, at 11:42 AM, Eugene Pasyuk < pasyuk at jlab.org > wrote:

>> Hi Volker,

>> This extra peak is coming from the endcap of the heat shield.
>> The difference between g9a and g9b is that the length of the holding magnets is
>> different.
>> Solenoid is shorter than dipole. In g9a we had carbon target mounted directly on
>> the endcap. If would do the same in g9b it would be too far from the main
>> target so we mounted it inside the magnet, but we still had to have endcap
>> which is a thin aluminized foil. And you see it. It g9a it is sitting at the
>> same place as carbon.
>> Actually this may be an explanation of "hydrogen contamination of carbon" we see
>> in g9a

>> -Eugene

>> ----- Original Message -----

>>> From: "Volker Crede" < crede at fsu.edu >
>>> To: "Eugene Pasyuk" < pasyuk at jlab.org >
>>> Cc: "Volker Crede" < crede at fsu.edu >, "priyashree roy" <
>>> roy.priyashree at gmail.com >
>>> Sent: Wednesday, March 16, 2016 11:08:49 AM
>>> Subject: FROST z-Vertex Distributions

>>> Hi Eugene,

>>> Priya and I are working on the comments we received for our analysis note. One
>>> issue the committee brought up is a bump in the z-vertex distribution in g9b
>>> between the carbon and polyethylene target (second attached figure). This peak
>>> is not present in g9a (first attached figure).

>>> Would you have any idea of what the origin of this peak might be?

>>> Cheers,

>>> Volker

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