Re: BCAL dimensions

[Tim Whitlatch <whitey@jlab.org>]

Hi Beni,

What we have in the 3D model right now is Lead/fiber matrix going from a 
radius of 65.05 cm to 87.6 cm. Outside of this is a 1.25 inch thick al 
plate. Inside, is the 8mm al plate. I am not sure of the last layer put 
on the wedge. George or Zisis can fill us in on this.

Cheers,

       Tim

Beni Zihlmann wrote:
> Hi calorimeter experts,
> I want to make sure that we have in the monte carlo a description of 
> the BCAL
> that comes as close as possible to what will be built in reality.
> Currently the following is in the MC.
> from radios 65 cm to 87.46 cm we have the lead/scintillator/glue 
> mixture  and then a  2.54 cm
> Aluminum plate.
> Now in the actual construction the last lead layer to be glued on will 
> be replaced by 8mm of Aluminum
> which corresponds to about the same radiation length as the 0.5mm 
> lead. In Order to reflect this in the
> MC I propose the following:
> make the active volume of the lead/scintillator/glue material 1.328mm 
> shorter and add 8mm of aluminum.
> the 1.328mm lead/scintillator/glue is 8.9958% of one radiation length 
> the same amount at the 8mm aluminum.
> In this way we will have only a difference of 0.8mm in thickness for 
> the whole BCAL wedge between what
> is in the MC and what will be built but we will have the same 
> radiation length.
>
> any opinions?
> Beni
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