Neutron multiplicities from spallation neutron sources were measured by Sol
id State Nuclear Track Detectors. Light particles as protons, deuterons and
alphas in the GeV range were used on Pb targets. For neutron thermalizatio
n the targets were covered by 6 cm paraffin moderator. Neutron multiplicity
distributions were studied inside and on the moderator surface. Comparison
of SSNTDs results were made for thermal-epithermal neutrons with La-139 ac
tivation method as well as with Dubna DCM/CEM code. Discussion including pr
evious C-12 results are given.