A. Putze et al.: An MCMC technique to sample transport and source parameters of Galactic cosmic rays. II. Table 5. Best-fit parameters on B/C data for the LBM. to K$_{0}$ (kpc 2 Myr − $^{1}$) ≈ 0 . 82 /λ$_{0}$ (g cm − $^{2}$). The LBM pa- rameters gathered in Table 5 are obtained from the above conversions, to ease the comparison with the DM results. For the different classes of models (I, II and III), a com- parison of Table 3 with the first three rows of Table 5 in- dicates that the same trend is found. For instance, model I (without reacceleration) has a larger δ than those with, and model II (without convection/rigidity-cutoff) has a smaller δ than those with. The slope for model III (with both convection and reacceleration) is in-between. This effect is more marked for the DM than for the LBM. We note that model II (with reacceleration but without convection) is al- most consistent with a Kolmogorov spectrum of turbulence, but is inconsistent with the data. Concerning the different datasets (A, C, and F), again, the same trend as for the LBM is found (compare Table 4 and the last three rows of Table 5). The most striking difference between the two models (LBM and DM) concerns their δ values. This difference can be explained in terms of non-equivalent parameterisation of the low-energy transport coefficient (see Maurin et al. 2010 for more details). Apart from this, both the value of the Alfv´enic speed and the normalisation of the diffusion coefficient K$_{0}$ in the two cases are fairly consistent when similar values of δ are considered. All the previous conclusions were derived for L = 4 kpc, but hold for any other halo size. The evolution of the transport parameters with L is shown in Fig. 5 (the best-fit values are consistent with those found in Maurin et al. 2002). In the three upper figures, we have superimposed the observed dependence a parametric formula. For K$_{0}$ (top panel), the formula can be understood if we consider the grammage of the DM. In the purely diffusive regime, we have λ$_{esc}$ ∝ L/K . This means that when we vary L , to keep the same grammage in the equivalent LBM, we need to vary K$_{0}$ accordingly. We find that K$_{0}$ = 1 . 08 × 10 − $^{3}$( L/ 1 kpc) 1 . 06 kpc 2 Myr − 1 instead of K$_{0}$ ∝ L . The origin of the residual L 1 . 06 dependence is unclear. It may come from the energy loss and gain terms. For the reacceleration, the interpretation is also simple. From Eq. (5), V$_{a}$ should scale as √$_{K}$$_{0}$$_{, so that}$ V$_{a}$ ∝ √$_{L}$$_{.}$ We find V$_{a}$ = 18 . 21( L/ 1 kpc) 0 . 53 km s − $^{1}$. This is ex- actly V$_{a}$ ∝ √$_{K}$$_{0}$$_{, with the dependence}$ √$_{L}$ 0 . 06 as above. The quantities V$_{c}$ and δ are roughly constant with L . The χ 2 min surface is rather flat, although a minimum is observed around L ∼ 15 kpc (the presence of a minimum may be related to the presence of the decayed $^{10}$Be into $^{10}$B in The transport parameters for both LBM (Paper I) and 1D DM, when fitted to existing B/C data, are consistent with both convection and reacceleration. The correlations be- tween the various transport parameters, as calculated from the MCMC technique, are consistent with what is expected the B/C ratio). This flatness is a consequence of the de- generacy of K$_{0}$/L when only stable species are considered. Consequently, an MCMC with L as an additional free pa- rameter does not converge to the stationary distribution. A sampling of the Galactic halo size is possible if radioac- tive nuclei are considered to lift the above degeneracy (see Sect. 5). Fig. 5. Best-fit parameters (III-F) as a function of the halo size of the Galaxy (blue circles). From top to bottom: K$_{0}$ , V$_{a}$ , V$_{c}$ , δ , and the associated χ 2 $_{min}$. In the first three figures, a parametric function matching the observed dependence is shown (dashed-red line). 4.4. Dependence of the parameters with L Model K best 0 × 10 2 δ best R 0 V best a χ $^{2}$/d.o.f Data (kpc $^{2}$Myr $^{$_{−}$1}$) (GV) (km s $^{$_{−}$1}$) I-F 2.36 0.56 5.70 . . . 5.52 II-F 5.26 0.38 . . . 65.1 1.78 III-F 4.19 0.43 2.94 53.9 1.56 III-A 2.32 0.57 4.40 11.3 2.71 III-C 4.13 0.44 3.10 53.6 2.26 III-F 4.19 0.43 2.94 53.9 1.56 ] -1   Myr 2 [kpc 0 K -3 10$^{-2}$ 10$^{-1}$ 10 1.06  L -3 =1.08 10 0 K ] -1  [km s a V 2 10 0.53 =18.21 L a V ] -1  [km s c V 18.5 19 19.5 0.016 =18.38 L c V 0.84 0.86 0.88 L [kpc] 1 10 /d.o.f 2 1.45 1.5 1.55 4.5. Summary of stable species and generalisation to the 2D geometry 8