Re: BCAL dimensions

[Beni Zihlmann <zihlmann@jlab.org>]

Hi George,
Thank you for this info, I was under the assumption that the aluminum 
would also be grooved.
Can you tell me then what the exact dimensions will be for the 
lead/scintillator matrix of one module?

cheers,
Beni
> Hi Beni:
>
> It's my understanding that the 8 mm Al plate glued in the inner face of
> the BCAL will be glued on top of the last Pb layer not the fibers.  I
> worry that the non-grooved Al plate will not adhere to the fibers and
> any delamination there will pull fibers out!  If we glue the plate on
> the last Pb layer, we can use industrial epoxy, the same we use for the
> base Pb layer, and assure that the Al-Pb bond is the strongest possible.
>  This will make it also more robust for the machining stages.
>
> George
>
>   
>>>> Beni Zihlmann <zihlmann@jlab.org> 07/16/08 2:27 PM >>>
>>>>         
> 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
>
>