[Halld-tagger] Microscope upper support

[Alexander Somov]

Thanks Richard,

I was asking about alighnment of counters; we are not going to
dinamically change the betta angle, it's clear. How do you want
your detector box be mounted on the upper platform ?
Do we rotate the whole box for alignment (or when we decide to move
the microscope to a 6 GeV region).

Cheers,
        Alex



On Tue, 26 Feb 2013, Richard Jones wrote:

> 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
>>>> 
>>>> 
>>>> 
>>>> 
>>> 
>>> 
>>> 
>
>
>