Two-neutron removal cross sections from 15,16C at around 240 MeV/nucleon

The cross sections for two-neutron removal from C-15(,)16 on a carbon target have been measured at around 240 MeV/nucleon. The measured cross section for C-15 is smaller than for C-16. The trends of the cross sections for C-15(,)16 are inconsistent with the previously reported experimental data, but in agreement with the theoretical predictions based on eikonal-model calculations. Based on the present results of C-15(,)16 combined with the available experimental data on C17-20, an odd-even staggering of the two-neutron removal cross sections along the neutron-rich carbon isotopic chain from C-15 to C-20 is observed, and this feature is well reproduced by the theoretical calculations.