| Popis: |
We have performed an experimental study of the angular and momentum distributions of fragments emitted from central collisions between emulsion nuclei (AgBr) and heavy-ion projectiles /sup 4/He, /sup 1/6O, and /sup 4/0Ar at beam rigidity 5.72 GV. Central collisions are here defined as interactions that exhibit an absence of projectile fragmentation, i.e., no beam-velocity fragments are produced within 5/sup 0/ of the incident beam direction. Production angles have been measured for all fragments having a restricted gain density g > or = 2g/sub min/, corresponding to protons of E < or = 250 MeV. Both range and angle measurements have been made for fragment ranges < or = 4 mm, corresponding to protons of E < or = 31 MeV. The data are analyzed in terms of a modified Maxwell-Boltzmann distribution from which we obtain estimates of the longitudinal velocity ..beta../sub parallel/ and the characteristic spectral volocity ..beta../sub 0/ of the particle-emitting systems. We find that no unique Maxwellian distribution can account for the observed fragment distributions. The angular distributions do not display statistically significant structure attributable to collective phenomena. |
