Track reconstruction with the silicon strip tracker of the proton CT Phase 2 scanner

We present algorithms for the proton track reconstruction for the Phase II proton CT scanner designed and built by the pCT collaboration. The entrance and exit telescopes of the scanner consist of four planes of silicon sensors with horizontal and vertical strips for proton track reconstruction. The goal of the track reconstruction is to allow usage of submillimeter voxels for subsequent image reconstruction. A dedicated algorithm was developed that recovers protons that traversed the dead areas at sensor joints and the dead or masked strips. The track reconstruction was tested on the data collected with 200 MeV protons from the proton synchrotron of the Loma Linda University Medical Center. Test results show that the reconstruction accuracy is close to the geometric limit of the strip sensors and multiple Coulomb scattering of the protons in air, sensors and scanning object.