Design and simulation of neutron radiography system based on 241Am–Be source

Neutron imaging is extended rapidly as a means of non-destructive testing (NDT) of materials. Various effective parameters on the image quality are needed to be studied for neutron radiography system with good resolution. In the present study a portable system of neutron radiography has been designed using 241Am–Be neutron source. The effective collimator parameters were calculated to obtain relatively pure, collimated and uniform neutron beam. All simulations were carried out in two stages using MCNPX Monte Carlo code. In the first stage, different collimator configurations were investigated and the appropriate design was selected based on maximum intensity and uniformity of neutron flux at the image plane in the outlet of collimator. Then, the overall system including source, collimator and sample was simulated for achieving radiographic images of standard samples. Normalized thermal neutron fluence of 2.61×10−5 cm−2 per source particle with n/γ ratio of 1.92×105 cm−2 μSv−1 could be obtained at beam port of the designed collimator. Quality of images was assessed for two standard samples, using radiographic imaging capability in MCNPX. The collimated neutron beam in the designed system could be useful in a transportable exposure module for neutron radiography application.

► Neutron radiography is an important technique in NDT. ► A portable neutron radiography system has been designed based on 241Am–Be source. ► 241Am–Be has the advantage of long useful half life and causing the system portable. ► MCNPX, Monte Carlo code used to investigate the beam parameters and image quality. ► Effective parameters were calculated to obtain relatively pure and collimated beam.