PAINUC

The PAINUC experiment is a joint collaboration among National Institute of Nuclear Physics of Torino, Dipartimento di Fisica Generale of Turin University and Joint Institute for Nuclear Research in Dubna (Moscow). Its aim is the study of nuclear matter in the energy range where the Delta(1232) resonance excitation occurs.

Within this range, the hadron gas state transition has been observed for heavy nuclei, but no information .exist about the light nuclei. Moreover, while at lower energies and in the case of elastic reactions the models developed on the basis od the nucler optical potential and its modifications (Laplacian, Kissingler) succed in describing such systems, within this range of energies they fail; besides QCD is valid at higher energies, where the scatering event can be considered a single qq scatter event.  

The experimental setup is based on a Self Shunted Stremer Chamber filled with He4 at 1 atm with automatic stereo image capturing by a pair of CCD within a 0.65 T magnetic field. The images taken with the spectrometer allow for a complete kinematical reconstruction of the event: information bout the energy loss and momentum of each charged particle taking part to the event are available.  The low density target and the  SSSC technique allow for a heavy particle recoil to be registerd and measured; e.g. a alpha particle of T=5 MeV has a track length of 20cm and can be readily measured. The SSSC is a unique candidate for the intermediate energy region studied.

The lack of knowledge about nuclei at intermediate energies makes the experimental approach to this field of research necessary. The direct observation of all the allowed reaction channels and the discovery of exotic effects, resonant or weakly bound states can give information about the structure of light nuclei, the nuclear potential and also about the subnucleonic structure of nuclei.