sPHENIX is a new detector at RHIC.

[Itaru Nakagawa <itaru AT bnl.gov>]

Dear Collaborators,

I  have some comments on the material budget of INTT.

On 2017/02/23 15:21, David Morrison wrote:
> [Current Tracking Issues by Tony Frawley]
>
>      Tracking system is moving to more realistic geometry.
>          Updated MAPS and INTT from cylindrical geometry to ladders.
>          INTT is proving to be twice as thick in the realistic geometryt
> as in the cylinder cell geometry. This caused the Upsilon mass width to
> be wider than specs. RIKEN is exploring possibility to improve tracking
> to mitigate this effect.
The current GEANT model is overestimating the material, particularly HDI 
part for following reasons.
1) The signal layers are assumed solid copper plane.
2) The solid plane bias and GND layers to be replaced by mesh pattern.

These will reduce the material budget down to less than 1% level per 
ladder even including the overlapping ladder.

We will update the GEANT model soon.

Best regards,
-itaru