RIPEN is a neutron detector system installed in the experimental Hall 3 in LNL. It is a modular array of BC501 liquid scintillators modules mounted in a spherical geometry all around the target. This latter one is hosted in a thin metal scattering chamber (1m diameter) which allows for the use of other specific detectors under vacuum for coincident measurements with charged ejectiles. The detectors mounted at the moment in the array are 24 and some spares are available at LNL. There is room for an increase of detection modules in the array if needed by the experiments.

In many physics cases connected with reactions induced by the SPES neutron rich beams, the access to some neutron information is highly desirable. Therefore in 2010 a recovery of this facility successfully started. The performances of the BC501 liquid scintillators have been successfully checked. A request for the funding of a new Front End Electronics power supply system has been submitted. By exploiting the expertise in the group (who strongly overlaps with the GARFIELD, 8PLP and FAZIA activities), fast digital electronics will be adopted: in this way we will better perform neutron-gamma separation via PSA and we will more easily handle the coupling with other future detectors already equipped with digital electronics for analogic and timing information and for triggering purposes. The purpose of the group is to have the detector fully operational by the end of 2011.

Presently, the RIPEN physics program mainly deals with fusion and fusion-fission experiments. Neutron energy spectra in low energy fusion reactions can give access to the nuclear level density; coincident measurement of neutrons and fission fragments can complete the information obtained from charged species about scission times and fission fragments properties. In this respect RIPEN is in strict contact with other initiatives in LNL (FAZIA, GARFIELD, 8PLP) and synergies are active with NEDA, ORIONE about neutron detector developments.
Collaboration with foreign groups are restarting (INDIA, USA).

View of the RIPEN neutron array structure with
the vacuum scattering chamber at the centre


Legnaro contact person: dr. M. Cinausero

RIPEN missing link