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Abraded nucleon spectrum

Cucinotta has examined different formulae to represent the secondary protons spectrum from heavy ion collisions [3]. One of the models (which has been implemented to define the final state of the abrasion process) represents the momentum distribution of the secondaries as:

$\begin{displaymath} \psi (p) \propto \sum\limits_{i = 1}^3 {C_i \exp \left( { - ... ...t)} + d_0 \frac{{\gamma p}}{{\sinh \left( {\gamma p} \right)}} \end{displaymath}$

(26.22)

where:

$\psi (p)$ = number of secondary protons with momentum $p$ per unit of momentum phase space [c/MeV];

$p$ = magnitude of the proton momentum in the rest frame of the nucleus from which the particle is projected [MeV/c];

$C1$ , $C2$ , $C3$ = 1.0, 0.03, and 0.0002;

$p1$ , $p2$ , $p3$ = $\sqrt \frac{2} {5} p_F$ , $\sqrt \frac{6} {5} p_F$ , 500 [MeV/c]

$p_F$ = Momentum of nucleons in the nuclei at the Fermi surface [MeV/c]

$d_0$ = 0.1

$\frac 1 \gamma$ = 90 [MeV/c];

G4WilsonAbrasionModel approximates the momentum distribution for the neutrons to that of the protons, and as mentioned above, the nucleon type sampled is proportional to the fraction of protons or neutrons in the original nucleus.

The angular distribution of the abraded nucleons is assumed to be isotropic in the frame of reference of the nucleus, and therefore those particles from the projectile are Lorentz-boosted according to the initial projectile momentum.

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