[Halld-cal] FCAL Monitoring

[Matthew Shepherd]

Hi George and Christine,

I'm cc'ing John on this, so he can respond if needed.  Octagonal sheet is fine.  I think it would actually be better since you could use the cutout corners to place monitoring electronics.

Regarding spacing from the front of the bars:

The bar itself as a 1/8" thick face plate on the front end.  This sets the minimum distance the acrylic can be from the bar:  1/8" if the acrylic touches this plate.  However, I don't think we want the two to touch since any vibration could create scratches in the acrylic that develop over time, thereby modifying the light output.  Probably a gap of 1/4" or so would be best.  This means a total distance of 3/8" or about 10 mm.

-Matt


On Feb 25, 2011, at 7:46 AM, Georgios Voulgaris wrote:

> Hi Matt,
> 
>   We have couple of questions for John :
>      Is it mechanically possible  to  support an octagon sheet (in four quarters) ?
>      Can we place the L.glass bars closer to the sheet?
> 
> Plexiglas with a thickness from 10 mm to 15 mm is O.K.
> LED boards can be glued directly on the sides of the sheet.
> We have some .5'' sheet in stock, for a test set up.
> 
> By,
> George.
> 
> Matthew Shepherd wrote:
>> Hi George and Christine,
>> 
>> Attached to this message is a quick sketch that John Frye made that is a rough conceptual design for how to mount the acrylic pane in front of the FCAL.  I think this conveys the general idea.  What we don't know is how you plan to integrate your LED pulsing system into this.  Where should boards go?  Should we revise to the design slightly so it could be detached as a single unit (for example, if we want to do UV curing of the glass)?  At our last meeting there seemed to be some confusion about the general concept and geometry, so this is maybe a good place to start.
>> 
>> Matt
>>  
>