Salamanca, July 2002 Geant4 simulation of the energy loss of slow negatively-charged hadrons Stephane Chauvie José M. Fernández-Varea Vladimir N. Ivanchenko Petteri Nieminen Maria Grazia Pia (for the Geant4 low-energy e.m. group)
Energy loss of heavy charged particles Salamanca, July 2002 Energy loss of heavy charged particles Electronic stopping power (1st Born approx.) Stopping number Inelastic form factor
If the ground state is isotropic Salamanca, July 2002 If the ground state is isotropic High-energy behaviour (Bethe formula) Born-series expansion Antiprotons: Z = -1 (no charge-exchange effects)
The quantal harmonic oscillator model Salamanca, July 2002 The quantal harmonic oscillator model Stopping number of an atom (= ensemble of oscillators) Frequencies & oscillator strengths Constraints These quantities are normally obtained from available optical or dielectric data
Nominal plasma frequency Salamanca, July 2002 Simplified model Nominal plasma frequency Sternheimer parameter a ~ e1/2 = 1.65 For other heavy negative hadrons
Geant4 implementation of the model Salamanca, July 2002 Geant4 implementation of the model
Salamanca, July 2002 Results (i) Continuous curve: antiproton; dashed curve: proton; symbols: exp.; dot-dashed curve: non-linear calculation.
Salamanca, July 2002 Results (ii) Continuous curve: antiproton; dashed curve: proton; symbols: exp.; dot-dashed curve: non-linear calculation.
Salamanca, July 2002 Results (iii) Continuous curve: antiproton; dashed curve: proton; symbols: exp.