CSI-crystal-barrel at LEAR

A detector system for kinematically complete measurements in the antiNN-system at rest and in flight for the post-ACOL era of LEAR is discussed. Its large solid angle (approximately equal 99% of 4π) will allow the reconstruction of complicated many particle resonances, and thus a sensitive search for nonexotic (qantiq) and exotic (glue balls, hybrids, ...) states in the mass region up to 2.5 GeV. The main part of the system is a modular (approximately equal 1200 modules) CsI-barrel-detector with photodiode readout placed in a superconducting magnet producing a homogeneous field of 1.6 T. The momenta of the charged particles will be measured in a cylindrical drift chamber of high spatial resolution. The components of the system are discussed in detail and price estimates are given. From MC-simulations the sensitivities for selected rare events are determined. 4 refs