Typically the 6 main kaon decay modes, beam pions, beam protons and K+→ π+ ν ν are available in two variants: standard decay region (102-180m) and extended decay region (102-265m), for trigger studies. Other samples are available on request.
The MC files are easily accessible at CERN (twiki).
Test productions at CERN
The MC files are placed on CASTOR /castor/cern.ch/na62/offline/mc/prod; a replica of the most recent ones can be found on EOS /eos/na62/data/offline/mc/prod
It usually consists of 1M events for each of the 6 main decay modes and the signal, with the addition of halo muons, 100M beam pions and 100M beam protons.
File lists of the available samples can be found under
There is a subdirectory for each year-specific configuration and one using design parameters.