[Halld-tagger] Microscope upper support

[Richard Jones]

Alex,

That angle is a fixed function of position along the focal plane. The position along the focal plane and the beta angle are fixed at the time when the detector is mounted.  To change either of these two requires dismounting the box from the focal plane and making adjustments, then reinstallation on the mount.

The reason for this choice is that those two parameters are fixed by the dipole geometry and position on the focal plane, do not vary much with the beam tune.  If the incidence angle thetaH of the electron beam in the horizontal plane at the radiator changes a tiny bit, then the energy bite of the microscope on the focal plane changes to leading order in thetaH, but the beta angle at a fixed position on the focal plane only changes to second order, ie. is stable.  Therefore one does not need dynamic control over the beta angle.

However, if the incidence angle thetaV of the beam at the radiator changes in the vertical plane, the impact of the electrons on the focal plane moves up and down, even at leading order in thetaV. Because this is a first-order effect, we want remote control to be able to optimize the alignment in real time.

-Richard J.


On 2/26/2013 11:45 AM, Alexander Somov wrote:
>
> Ok, thanks. How do we change counter's angle with respect to
> electrons, rotate the whole box ?
>
> Alex
>
>
>
> On Tue, 26 Feb 2013, Richard Jones wrote:
>
>> Alex,
>>
>> There is no translation along the focal plane or rotation around fixes axes, just three independent elevation points with 10-15mm of vertical motion range each.   There are 3 step motors needed. The drawings on our wiki are 3D autocad files that show placeholders for the three motors located under the three support points of our upper enclosure.  Please look at the "upper enclosure drawing" link on the wiki page below.
>>
>> http://zeus.phys.uconn.edu/wiki/index.php/Full_Scale_Tagger_Microscope_Drawings#Updated_Design_For_Upper_Enclosure
>>
>> -Richard Jones
>>
>>
>>
>> On 2/26/2013 9:44 AM, Alexander Somov wrote:
>>>
>>> Hello Richard,
>>>
>>> We need to know some specs on the microscope upper support
>>> table (frame):
>>> translation range along the focal plane, and vertical direction (Y), rotation angles (?)
>>>
>>> How many step motors we will need (I don't think that the design should be
>>> complicated, perhaps some angles can be adjusted manualy).
>>>
>>> Could you make a sketch for us containing some dimentions.
>>>
>>>
>>> Thanks,
>>>        Alex
>>>
>>>
>>>
>>>
>>
>>
>>


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