Target multifragmentation of KEK-PS. Inclusive measurement

When a high energy hadron collides with a heavy nucleus such as Au and Pb, the emission of several intermediate mass fragments (IMFs) is often observed. This process is called multifragmentation. It is considered that IMFs are emitted from highly excited nuclear system, and carry the information on its matters. The nuclear multifragmentation experiment was performed by using 12 GeV proton beam and 20 GeV α beam together with a multi-counter system. The inclusive energy spectra and the angular distribution of IMFs were measured. Also the coincidence measurements of some IMFs were performed. The experiment was performed at the P1 beam line of the 12 GeV proton synchrotron in the National Laboratory for High Energy Physics (KEK-PS). Proton beam and α beam were used to bombard Au or Ag target. The IMFs produced in the interaction of the incident particles with the target nuclei were detected with Bragg curve counters (BCCs). The BCCs are gas ionization counters which can determine the atomic numbers and the kinetic energy of IMFs simultaneously. The experimental setup is shown. Bragg peak height vs. kinetic energy, the energy spectra of Na isotopes, the angular distribution of produced IMFs and so on are reported. (K.I.)