Development of a neutron imaging facility at the CENM Al Maâmora TRIGA

The field of neutron imaging has a broad scope of applications and has played a pivotal role in visualizing and quantifying hydrogenous masses in metallic matrices. The field continues to expand into new applications with the installation of new neutron imaging facilities. In this scope, a neutron imaging facility for computed tomography and real-time neutron radiography is currently being developed around 2.0 MW TRIGA MARK-II Reactor at Maâmora Nuclear Research Centre in Morocco (CENM). The neutron imaging facility consists of neutron collimator, real-time neutron imaging system and imaging process systems. In order to reduce the gamma-ray content in the neutron beam, the reactor tangential channel was selected. For power of 250 kW, the corresponding thermal neutron flux measured at the inlet of the tangential channel is around 3.10¹¹ncm²/s. This facility will be based on a conical neutron collimator with two circular diaphragms with diameters of 4 cm and 2 cm corresponding to L/D-ratio respectively of 165 and 325. These diaphragms´ sizes allow to optimize between good flux and L/D-ratio. Convergent-divergent collimator geometry will be adopted. The collimator system consists of a beam scatter, gamma filter, fast neutron filter, thermalization column, neutron and gamma shutters, biological shielding around the collimator, and several stages of neutrons collimator. Monte Carlo calculations by a fully 3D numerical code GEANT4 were used to design the neutron collimator system. The neutron imaging system will be used for material studies and nondestructive inspection applications.