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Re: tagger field map
Tim,
I agree with this. It is a very small change to the optics, given the
small angles involved, so I expect that any changes to the results we
presented in November will be absolutely negligible -- except to put the
exit beam back where the machine group wants it. The focal plane will
translate by the same amount, with no changes in detector offsets or angles.
Richard Jones
Tim Whitlatch wrote:
> This means that we move the radiator, Quad and tagger downstream 19.6 cm?
>
> Tim
>
> Guangliang Yang wrote:
>> Dear Sascha,
>>
>> I got the same result, dz=19.6cm.
>>
>> Cheers
>>
>> Yang
>>
>>
>>
>> ----- Original Message ----- From: "Alexander Somov" <somov@jlab.org>
>> To: "Elke-Caroline Aschenauer" <elke@jlab.org>
>> Cc: "Tim Whitlatch" <whitey@jlab.org>; "Guangliang Yang"
>> <y.guangliang@physics.gla.ac.uk>; <halld-tagger@jlab.org>
>> Sent: Monday, January 12, 2009 2:50 PM
>> Subject: Re: tagger field map
>>
>>
>>> Hello Elke,
>>>
>>> Ok, thanks, I also think that it's the simplest dicision.
>>>
>>> Yang, could you double check the shift (just to be consistent);
>>> I estimated it to be dz = ~19.6 cm.
>>>
>>> Cheers,
>>> Sascha
>>>
>>>
>>>
>>>
>>> On Mon, 12 Jan 2009, Elke-Caroline Aschenauer wrote:
>>>
>>>> On Mon, 12 Jan 2009, Alexander Somov wrote:
>>>>
>>>> Dear Sascha,
>>>>
>>>> as Tim already pointed out, we shift our things.
>>>> the tagger magnet and if needed also the quad. This is easiest
>>>> because it
>>>> does not involve any other parties like the machine group. And
>>>> there is
>>>> enough space in the tagger hall to do that, so please take this
>>>> mail as a
>>>> decission.
>>>>
>>>> thanks elke
>>>>
>>>>
>>>>
>>>>> Date: Mon, 12 Jan 2009 09:24:57 -0500 (EST)
>>>>> From: Alexander Somov <somov@jlab.org>
>>>>> To: Tim Whitlatch <whitey@jlab.org>
>>>>> Cc: Guangliang Yang <y.guangliang@physics.gla.ac.uk>,
>>>>> halld-tagger@jlab.org
>>>>> Subject: Re: tagger field map
>>>>>
>>>>>
>>>>> Good morning,
>>>>>
>>>>> Yang thanks for the information.
>>>>>
>>>>> The question is should we shift the magnets or the
>>>>> electron beam pipe which goes to the dump (downstream
>>>>> by 19.6 cm)?
>>>>>
>>>>> Should we shift the quadrupole magnet as well (or one can
>>>>> simply change the quadrupole's field) ?
>>>>>
>>>>> Cheers,
>>>>> Sascha
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> On Mon, 12 Jan 2009, Tim Whitlatch wrote:
>>>>>
>>>>>> Good morning all,
>>>>>>
>>>>>> We do not wish to change the Tagger hall. Is there an exact
>>>>>> number that we
>>>>>> should shift the magnet by? Or is 20cm fine?
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>> Tim
>>>>>>
>>>>>> Guangliang Yang wrote:
>>>>>>> Dear Sascha,
>>>>>>>
>>>>>>> The number in table 4.2 was calculated for the two dipole
>>>>>>> tagger. It is
>>>>>>> not correct for the single magnet tagger. If we don't want to
>>>>>>> change the
>>>>>>> tagger hall design, we should shift the tagger downstream by ~20
>>>>>>> cm.
>>>>>>>
>>>>>>>
>>>>>>> Cheers
>>>>>>>
>>>>>>> Yang
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> ----- Original Message ----- From: "Alexander Somov"
>>>>>>> <somov@jlab.org>
>>>>>>> To: "Richard Jones" <richard.t.jones@uconn.edu>
>>>>>>> Cc: <halld-tagger@jlab.org>
>>>>>>> Sent: Friday, January 09, 2009 3:53 PM
>>>>>>> Subject: tagger field map
>>>>>>>
>>>>>>>
>>>>>>>>
>>>>>>>> Hello Richard,
>>>>>>>>
>>>>>>>> The magnetic field map in the tagger hall seems
>>>>>>>> to be shifted by a few cm in the MC.
>>>>>>>>
>>>>>>>> According to the table 4.2 in the technical design
>>>>>>>> report (updated for the review), the position of
>>>>>>>> 12 GeV electrons at z=26.301 m should be x = -4.7576 m.
>>>>>>>> However, I get x = -4.803 m, see the plot attached.
>>>>>>>> Are the numbers in the table 4.2 correct ?
>>>>>>>>
>>>>>>>> I used the same reconstruction code as before but just
>>>>>>>> replaced the magnetic field map (do I need to shift the
>>>>>>>> map ?)
>>>>>>>>
>>>>>>>> Could you please check. I want to finish with updating
>>>>>>>> geometry asap.
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>> Sascha
>>>>>>>>
>>>>>>>> P.S. The full-energy deflection angle in the magnet is
>>>>>>>> correct, 13.4 deg.
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>> ( `,_' )+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=
>>>> ) `\ -
>>>> / '. | +
>>>> | `, Elke-Caroline Aschenauer =
>>>> \,_ `-/ -
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>>>>
>>>> +=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+
>>>>
>>>>
>>>
>>>
>>