Derived CR proton spectrum of Sgr B region as defined in the text. The shaded regions are derived by assuming the mass of the Sgr B region is either 1.5 × 10⁷M_⊙ (aqua) or between 0.6−1.5 × 10⁷M_⊙ (“old lace” white). The crosses display the CR spectrum derived assuming a local CR spectrum, as per the PAMELA observations, whilst the grey hatched region represents the CR proton spectrum derived for the Orion B region derived in Yang et al. (2014).