SPES and the neutron facilities at Laboratori Nazionali di Legnaro

Abstract.

The SPES Radioactive Ion Beam (RIB) facility, now in the construction phase at INFN-LNL, has the aim to provide high-intensity and high-quality beams of neutron-rich nuclei for nuclear physics research as well as to develop an interdisciplinary research center based on the cyclotron proton beam. The SPES system is based on a dual-exit high-current cyclotron, with tunable proton beam energy 35-70MeV and 0.20-0.75mA. The first exit is used as proton driver to supply an ISOL system with an UCx Direct Target able to sustain a power of 10kW. The expected fission rate in the target is of the order of $10^{13}$ fissions per second. The exotic isotopes will be re-accelerated by the ALPI superconducting LINAC at energies of 10 A MeV and higher, for masses around $A=130$ amu, with an expected beam intensity of $10^7$ - $10^9$ pps. The second exit will be used for applied physics: radioisotope production for medicine and neutrons for material studies. Fast neutron spectra will be produced by the proton beam interaction with a conversion target. A production rate in excess of $10^{14}$ n/s can be achieved: this opens up the prospect of a high-flux neutron irradiation facility (NEPIR) to produce both discrete and continuous energy neutrons. A direct proton beam line is also envisaged. NEPIR and the direct proton line would dramatically increase the wide range of irradiation facilities presently available at LNL. We also present LENOS, a proposed project dedicated to accurate neutron cross-sections measurements using intense, well-characterized, broad energy neutron beams. Other activities already in operation at LNL are briefly reviewed: the SIRAD facility for proton and heavy-ion irradiation at the TANDEM-ALPI accelerator and the BELINA test facility at CN van de Graaff accelerator.