  Jet substructure variables for hadronic jets with transverse momenta in the
range from 2.5 TeV to 20 TeV were studied using several designs for the spatial
size of calorimeter cells. The studies used the full Geant4 simulation of
calorimeter response combined with realistic reconstruction of calorimeter
clusters. In most cases, the results indicate that the performance of
jet-substructure reconstruction improves with reducing cell size of a hadronic
calorimeter from $\Delta \eta \times \Delta \phi = 0.087\times0.087$, which are
similar to the cell sizes of the calorimeters of LHC experiments, by a factor
of four, to $0.022\times0.022$.
