Stopped Pi- Capture

Stopped pi- are captured in Ta.
  • Data reference: R. Madey et al., Phys. Rev. C 25, 3050 (1982).

Simulation Conditions

  • Geant4 version: 8.1
  • Models: CHIPS

Comments

  • Plot details:
    • Blue squares: data for neutrons, deuterons, tritons, 4He
    • Red circles: data for protons, 3He
    • Histograms: model predictions
    • Numbers in angle brackets (Ekin) give mean kinetic energy as experimental value over model-predicted value
    • The horizontal axis is in units of k, which is the average of the secondary particle's kinetic energy and momentum
  • Plot features:
    • Neutrons: the general shape of the data is reproduced, but the model under-estimates the data by a factor of 2 at the low energies and over-estimates by 50% at high energies.
    • Protons: the model under-estimates by a factor of 3 at the lowest energy data point, and over-estimates by a factor of 3 at high energies
    • Deuterons: good agreement up to 300 MeV, but the model remains much higher than the data points (by a factor of 30) at the end-point.
    • Tritium, 3He and 4He: model and data differ significantly, but spectral shapes are reproduced

Summary

  • The CHIPS model reproduces the qualitative features of the capture-generated secondaries, but significant differences with data suggest model tuning is necessary.

Plots

stopped pi- capture in Ta: CHIPS model