NEW LINES OF RESEARCH WITH THE MAGNEX LARGE-ACCEPTANCE SPECTROMETER

A new design of magnetic spectrometer, MAGNEX, is under construction for the INFNLNS, Catania. The unique features of MAGNEX are its solid angle of acceptance (51 msr), momentum acceptance (±10%), overall momentum resolution of 1/2000 and mass resolution of 1/200, together with a focal plane detector having a low detection threshold (0.5 MeV/A). The spectrometer is based on a 55° bend angle dipole magnet with mean radius of 1.6 m. It is designed for a maximum rigidity of 1.8 Tm. Despite the large acceptance, a good momentum resolution is achieved by a combination of careful ion-optical design and software ray-reconstruction. The latter depends on three things: the availability of detailed field maps, the precise measurement of position and angle by the detection system, and the solution to high order of the equation of motion based on, in our case, the program COSY INFINITY. The MAGNEX spectrometer, connected with the broad choice of both stable and radioactive beams at the LNS, will provide new opportunities for, e.g., spectroscopy of weakly-bound nuclei by direct reactions, reaction mechanisms with large isospin and nuclear astrophysics.