Neutron Radiography Neutron Slowing Down Of The MCNP Simulation

Neutron radiography is a non-destructive testing technology, and has been widely used is similar to the X-ray camera, is the use of radiation to penetrate the material to be detected, its intensity changes occurred in the attenuation characteristics of the access to objects within the image defect information . Neutron radiography has been more widely used in aircraft (wing, fuel tank, engine, etc.), spacecraft components, electronic circuits, metallurgical parts, pieces of organic adhesive, non-destructive testing of nuclear fuel components and the hydride testing. And has developed a more comprehensive technical standards for neutron radiography.Neutron radiography and X-ray photography X-ray camera compared irreplaceable advantages. Neutrons are not charged, it mainly occurred in the role of the nucleus, the absorption coefficient changes with the very rules of atomic number, such as heavy elements are on the neutron a lot of absorption, most of the heavy elements have smaller neutron absorption coefficient, therefore, the use of neutron radiography can detect light elements in the material or material wrapped with heavy elements of the light elements of the defect in the material (such as the density distribution, the gap, breaking marks, bubbles, etc.).Monte Carlo Method can realistically describe the random events and simulate the experiment courses. It is very suitable for the calculation of particle transport problem which has the random city. The method has been widely used in the simulation of nuclear experiments include neutron detection. MCNP is a general program to simulate nuclear experiments, which is made by Los Alamos Station Lab in America, based the Monte Carlo thoughts.In this paper, based on the principles of neutron radiography, the use of MCNP 4C procedures, the first simulation of a single material of 14MeV neutron slow, and then establish a model to discuss two kinds of material combinations on the slow neutron 14MeV of the situation, find the best combination of so that after the slow neutrons in the thermal neutron beam injection rate as much as possible in order to meet the needs of neutron radiography and to explore the simulation of such guidance on the experiment.