Speaker
Dr
Jelena Ninkovic
(Max PlanckInstitute for Physics)
Description
With a world-record integrated luminosity of 1/ab the Belle detector has impressively verified the CP violation in the B-meson system as formulated within the Standard Model (SM). On the other hand, Belle has also found some tantalizing hints, although statistically not yet significant, of new physics beyond the SM. In order to further explore this exciting field, an upgrade of the existing KEKB machine in Tsukuba, Japan, is planned. The new Super Flavor Factory, SuperKEKB, will be an asymmetric (4GeV,7GeV) e+e-collider, working at the center of mass energy of the Y(4S) resonance, achieving a luminosity 40 times higher than the KEKB machine. To fully exploit the physics potential of the new B-factory and to cope with the higher occupancy and radiation levels expected at SuperKEKB, an upgrade of the Belle detector is being pursued by the Belle II collaboration. The most challenging requirements of the new detector are precise vertexing and momentum measurements giving a good impact parameter resolution for low energy secondary particles. Hence a vertex detector must be designed to achieve a spatial resolution of 10μm and a material budget of 0.19X0 per layer to reduce as much as possible the multiple Coulomb scattering. This will be provided by a new silicon pixel vertex detector ("PXD") placed in the central region of the Belle II detector. The PXD will consist of the two layers of thin (75μm) DEPFET Active Pixel Sensors with radii at 14mm and 22mm. The inner layer consists of 8 planar sensors, each with a width of 15mm, and a sensitive length of 90mm. The outer layer consists of 12 modules with a width of 15mm and a sensitive length of 123mm. The sensitive lengths in each of the layers are determined by the required angular acceptance of the tracker. In this paper, an overview of the full system will be given, including the sensor, the front-end electronics and both the mechanical and thermal solutions specially designed for this system. Additionally, the expected performance of the detector system will be presented.
Author
Dr
Jelena Ninkovic
(Max PlanckInstitute for Physics)
