High energy heavy ions cannot penetrate water media

As the title says, I used 400MeV carbon ions to enter the water model, but strangely, it cannot penetrate the water model. Is it because the physical model is not selected correctly? Or for other reasons?

This is very strange. Are you using a Geant4 example?

from examples TestEm0 or TestEm1, we see that penetration of C12 (400 MeV) in water is ~ 3.6 mm. Is it what you observe ?

em0.mac.txt (328 Bytes)
em1.mac.txt (483 Bytes)

Try
/event/verbose 1
/tracking/verbose 1
in your macro and see, what process causes it stop at boundary.

Don’t forget, that Geant4 uses full energy instead of energy per nucleon in primary generator.

Sorry, I check the code again ,and …it’s my fault. I just make a mistake in my primarygenerator. Actually i am going to launch a 400MeV/u carbon ion, so the toal energy should be 400*12 MeV, but i was set the total energy to 400MeV.That’s the problem.

Yes, thanks for your reply!

Thx for your answer , I made a silly mistake… :rofl:

Don’t forget, that Geant4 uses full energy instead of energy per nucleon in primary generator.