  Fragmentation reactions induced on light and medium nuclei by protons and
light nuclei of energies around 1 GeV/nucleon and below are studied with the
Los Alamos transport code MCNP6 and with its CEM03.03 and LAQGSM03.03 event
generators. CEM and LAQGSM assume that intermediate-energy fragmentation
reactions on light nuclei occur generally in two stages. The first stage is the
intranuclear cascade (INC), followed by the second, Fermi breakup
disintegration of light excited residual nuclei produced after the INC. CEM and
LAQGSM account also for coalescence of light fragments (complex particles) up
to 4He from energetic nucleons emitted during INC. We investigate the validity
and performance of MCNP6, CEM, and LAQGSM in simulating fragmentation reactions
at intermediate energies and discuss possible ways of further improving these
codes
