Physics Division Seminars bring us speakers on a variety of physics related subjects. Usually these are held in the Building 6008 large Conference Room, at 3:00 pm on the chosen day, but times and locations may vary. For more information, contact our seminar chairman,
Tel (Office): (865) 574-6124 (FAX): (865) 574-1268
Antiproton-induced reaction studies will be one of the major physics programs of the FAIR facility at GSI, Germany. The HESR synchrotron and storage ring will provide a high luminosity (<2 × 1032 cm-2s-1) beam of cooled antiprotons up to a momentum of 15 GeV/c. The envisaged hadron physics program will focus on non-perturbative processes to study the structure of hadrons and their interactions. High resolution experiments will perform charmonium spectroscopy, search for gluonic excitations such as charmed hybrids or glueballs and will address open problems of in-medium modifications of hadrons.
The PANDA detector, consisting of a target and forward part with nearly 4 pi coverage, allows high resolution spectroscopy of all reaction species anticipating an annihilation rate of 107/s. As a major component, the central part houses inside a superconducting solenoid of 2 T magnetic field a homogeneous electromagnetic calorimeter providing sufficient coverage for multi-photon and multiple meson detection, a fast response, high granularity and excellent energy resolution for shower reconstruction over a large dynamic range of photon energies from 10 GeV down to as low as 10 MeV.
The present design is based on nearly 20,000 tapered 200-mm long scintillator crystals made of PbWO4 (PWO) readout via large area (10 x 10 mm2) avalanche photo diodes. In order to detect photons down to very low energies, a new generation of PWO with significantly increased light output (PWO-II) has been developed. To reduce thermal quenching, the calorimeter will be operated temperature stabilized at –25° C.
The presentation will outline in detail the detector concept, illustrate the quality and performance of the new developed crystals and photo sensors, and present first test measurements with prototype arrays using tagged photons up to 520 MeV. The excellent energy and time resolutions have been never reached before.