sPHENIX is a new detector at RHIC.

[Gunther M Roland <rolandg AT mit.edu>]

Friends,

Many thanks again to the members of the Inner Tracker Task Force and everybody else who helped with the task force studies, and to the participants of the yesterday's productive meeting!

As presented at the collaboration meeting, and discussed yesterday, the optimal INTT configuration needs to achieve a balance between minimizing material over the sPHENIX tracker and calorimeter acceptance and reliably providing crucial information for pileup disambiguation and tracker calibration. The principal parameter in this optimization is the number of INTT (sub-)layers, with the precise radial position of the layers, the sensor layout (z vs phi strips) and details of the stave design having a smaller performance impact. The task force recommended 2 layers (4 sublayers) to reliably and with sufficient redundancy provide at least 1INTT space point on each reconstructed trajectory. 

Following the recommendation by the task force and the EC discussion, we will proceed with a 2 layer INTT design with phi-strips for all sublayers. The task force and INTT team in consultation with the OSI will on a short time scale converge on the ladder type and radial position for the two layers, so that we can proceed to detailed mechanical engineering soon. The INTT team is encouraged to develop detailed specifications of the INTT performance and to maximize the number of available spares. The final design should ensure that the material budget within or close to the |eta| < 1.1 acceptance is optimized within the given constraints, e.g., through the margin between active area and support structures and choice of radial position.

Thanks again to everyone who participated, and Happy Holidays!

Gunther and Dave