BEAM FORMATION AND CHARACTERIZATION FOR NEUTRON RADIOGRAPHY

Abstract Neutron flux and geometrical parameters (L/D and D) have been used as principal parameters to characterize a neutron beam. The parameters are also important from the standpoint of obtaining a neutron beam which provides a high quality image. Aneffective energy of the neutron beam, which is easily modulated by insertion of filters, is also important, and the quantification of these parameters serves to extend the confidence in a neutron radiography (NR) facility. A new parameter, figure of merit F, is proposed as a measure of geometric effectiveness of the facility. The F value should be an indicator of the flexibility of existing facilities and should also provide guidelines for making modifications for improvement in performance and for designing new facilities.