Multiparametric approach to the assessment of muon tomographic results for the inspection of a full-scale container

Experimental results from a dataset collected with a full-scale muon tomograph for the inspection of cargo containers were studied in a single scattering scenario with a multiparametric analysis based on the method of the Point Of Closest Approach (Poca). To search for high-Z materials, a 4 dm^3 Pb block was positioned inside the volume to be inspected, in order to quantitatively investigate the appearance of the Poca signal. Signal-to-noise ratio and significance of the Poca signal were investigated by means of mono-dimensional spectra of the Poca components, for different values of the scattering angle between the incoming and outgoing muon tracks and with different angle-dependent weights. A systematic scan of two-dimensional maps was also carried out, as a strategy to search for possible enhancements to the Poca signal. A comparison was also done between the results obtained from the two half-volumes, one containing the Pb block and one left empty, to take into account the response of the detector and some aspects of the Poca strategy.