1. An active radiation source portal monitoring system comprising: a particle accelerator as a source of charged particles; a target unit that receives the charged particles including protons, wherein a nuclear interaction between the protons and atomic nucleus of the target unit produces other particles including pions; a beamline unit to allow the produced pions to decay into muons; a selection unit to select the muons having specific values of momentum; a charged particles control unit to control the charged particles, including the muons, to enter into a volume to be scanned in a desired direction to interact with an object located in the volume; a particle tracking unit arranged at a location near the volume to detect the charged particles exiting the volume after interacting with the object and generate signals indicative of information on the charged particles exiting the volume; and a signal processing unit communicatively coupled to the particle tracking unit, the signal processing unit to receive the generated signals and to analyze scattering of the charged particles, including the muons, in one or more materials included in the object based on the received signals indicative of the information on the charged particles exiting the volume to obtain a tomographic profile or a spatial distribution of scattering centers within the object.