Check energy units for energy loss distribution for helium ions

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Should we use energy per nucleon or absolute kinetic energy

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Lets start with 150 MeV/nucl helium ions impinging water target.

NIST ASTAR database https://physics.nist.gov/PhysRefData/Star/Text/ASTAR.html predicts stopping power 2.167 keV/um.

The same can be obtained from libdedx https://aptg.github.io/web_dev/Calculator:

note that 600 MeV/nucl is outside the range of ASTAR, but Bethe equation does the job:

On the other hand energy loss for 150 MeV/u helium ions in water is much below 2keV/um