[Frost] Tagger correction analysis

[Eugene Pasyuk]

Mike, this tracking phi is not azimuthal but polar angle. This phi is 
the same as theta in usual convention.

-Eugene


Michael Dugger wrote, On 10/12/10 17:56:
>
> Hi,
>
> The only azimuthal asymmetry (downstream of z=-2.6 cm) in the target
> blueprints, is the wave guide, and that should be directly beneath the
> Butanol target.
>
> I don't have the blueprints for the start counter. Where can I find them?
>
> -Michael
>
> On Tue, 12 Oct 2010, Eugene Pasyuk wrote:
>
>> Hi Brian,
>>
>> Interesting results. I thing it gives us some clues. Particularly those
>> depletions in phi distributions. The dip for CH2 at ~1.6 radians (close
>> to 90 degrees) is probably coming from the fact that when particle is
>> emitted perpendicualrly to the beam it passes through the significant
>> amount of material. On average equal to the radius of the target which
>> is 7.5 mm. The is seen only for pions because protons just dont go at
>> these large angles. Now we need to look in the geometry and find what
>> corresponds to 0.6 radian from the center of butanol and 0.4 radians
>> from the CH2. It must be some thick material along this direction or
>> some corner of volume.
>>
>> Brian M. and Mike: could you take a look at this? You figured out all
>> the geometry. It also may be related to the start counter. We need to
>> check if the ST offset is correct.
>>
>> -Eugene
>>
>>
>>
>>
>>
>>
>> On 10/12/10 3:28 PM, Brian Vernarsky wrote:
>>> Greetings FROST list,
>>>
>>> I have been continuing to work on the discrepancy between the targets
>>> in the tagger correction and to that end have looked into the proton
>>> momentum and the energy loss calculations. I have put together a
>>> document presenting all that I've looked into which is linked below.
>>> I present a few questions or discrepancies I wouldn't expect, but
>>> there may be valid reasons for them to exist, so please let me know if
>>> you see anything that has an obvious answer or reason. Please let me
>>> know if you have any questions. The document can be found at:
>>>
>>> http://www.andrew.cmu.edu/user/bvernars/FROST_tagger_update_10_12_2010.pdf
>>>
>>>
>>> Brian
>>> _______________________________________________
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>>> Frost at jlab.org
>>> https://mailman.jlab.org/mailman/listinfo/frost
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