Evaluation of the ATLAS-MPX devices for neutron field spectral composition measurement in the ATLAS experiment

A network of 15 Medipix2-based devices (ATLAS-MPX devices) has been installed at various positions in the ATLAS detector within the framework of the ATLAS-MPX collaboration. The aim of the network is to perform real-time measurement of spectral characteristics and composition of the main radiation types in the experiment including slow and fast neutrons, especially during the initial low luminosity LHC operation. This contribution describes the network structure and focuses on the neutron efficiency calibration process of the ATLAS-MPX devices and its simulation in order to predict the behavior of the device in complex neutron fields.