MONDO – Monitor for Neutron Dose in hadrOntherapy – is a project dedicated to the characterisation of secondary neutrons produced by the interactions of the particle therapy beams with the patient. In fact, neutrons can release a significant dose even far away from the irradiated tumour region. The MONDO detector exploits the double elastic scattering of neutrons on a matrix of thin plastic fibres in order to reconstruct the direction and energy spectrum of the incoming neutrons. Some prototypes in small scale have already been realised, taking advantage of SIR2014 funds of the MIUR, and the construction of a “full size” detector in going. In addition to the tracer matrix a dedicated sensor has been developed for the readout of scintillating fibers. The sensor SBAM (Spad-Based Acquisition readout for the Mondo experiment) is developed in collaboration with the Fondazione Bruno Kessler of Trento. The first sensor has been built and is now in the test and calibration phase.