Prediction of concentration evolution over a time interval on an Eulerian grid

Exponential attenuation models for neutrons and muons

solv_conc_eul(z, ero, t, C0, p, S, L, in_ero = NULL)

Arguments

z

depth coordinate of the profile (g/cm2)

ero

erosion rate (g/cm2/a)

t

time interval (a)

C0

inherited concentration constant with depth (at/g)

p

production and decay parameters (4 elements vector) p[1] -> unscaled spallation production rate (at/g/a) p[2] -> unscaled stopped muons production rate (at/g/a) p[3] -> unscaled fast muons production rate (at/g/a) p[4] -> decay constant (1/a)

S

scaling factors (2 elements vector) S[1] -> scaling factor for spallation S[2] -> scaling factor for muons

L

attenuation lengths (3 elements vector) L[1] -> neutrons L[2] -> stopped muons L[3] -> fast muons

in_ero

initial erosion rate yielding a steady state inherited concentration (g/cm2/a), C0 not used in this case