Re: updated geometry

[Richard Jones <richard.t.jones@uconn.edu>]

Beni,

Yes we should have as much of reality as is relevant for performance, 
and certainly this plate will affect the performance.  But it simply 
cannot be there if we want to measure low-energy photons.  Perhaps we 
can let the MC studies show that, but I don't think we need MC to know 
what the result will be.  I would say that our concern about the FDC 
cables pales in comparison with this.

Richard Jones

Beni Zihlmann wrote:
> Hi Richard and All,
> indeed I forgot to adjust the overall module volume to accommodate for 
> the inside aluminum plate. I can/will fixt that in a second.  But now 
> I have a question to your comment. I agree that an 8mm aluminum plate 
> inside the BCAL surface will degrade the resolution but that is 
> exactly what is in the drawings to build the BCAL and Elke asked me to 
> put it into the geometry. Don't we want to have the studies to be made 
> by Matt et al. having a geometry as close as possible to reality?
>
> cheers,
> Beni
>
> Btw. yes I am really interested in your tools.
>
>
> Richard Jones wrote:
>> Beni, some work is still needed on this geometry.  The following 
>> items are invalid, so that no particle will ever be able to enter 
>> their volumes.  This is not a comprehensive list, just the result of 
>> a quick spot check I did.  I have a tool that can enables a quick 
>> point-and-click check on individual volumes.  I can show you how to 
>> use it, if you are interested.
>>
>>    1. FDC cables re-routed to run upstream
>>    2. 8mm aluminum plate in front of BCAL
>>
>> That aluminum 8mm plate will completely wipe out the BCal resolution, 
>> once it is in there!  For the moment, however, it causes no problems 
>> at all, because particles do not see it. :-)
>>
>> -Richard Jones
>>
>>
>> Beni Zihlmann wrote:
>>> Dear colleagues,
>>> I updated the geometry in the repository. The geometry now reflects
>>> all the changes and design decisions that have been made lately.
>>> 1) remove outer most CDC layer thereby reducing the CDC radius by 
>>> 1.6 cm
>>>    including the cable runs.
>>> 2) re-route the FDC cables to run upstream
>>> 3) add an 8mm aluminum plate on the inside of the BCAL
>>> 4) the BCAL readout segmentation is 4x6 (sector x layer)
>>>
>>> all these changes are now available the in geometry file 
>>> hddsGeant3.F located in
>>> src/programs/Simulation/HDGeant/
>>>
>>> cheers,
>>> Beni
>>>
>>
>
>