[Frost] Tagger correction analysis

[Eugene Pasyuk]

Yes it is :o)

Tracking is done in sector coordinates. phi is angle between the track 
an beam and lambda is angle across the sector.

-Eugene

Michael Dugger wrote, On 10/12/10 18:06:
>
> That is confusing :(
>
> Thanks for the information.
>
> -Michael
>
> On Tue, 12 Oct 2010, Eugene Pasyuk wrote:
>
>> 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
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