CAD Model and CR and MRI Scan Data to MCNP Input Format Conversion Software

We will develop two programs to process data describing a model geometry and convert it to input acceptable to the Monte Carlo transport codes MCNP and MCNPX. One program will read CAD files in the ACIS solid body SAT format. Solid bodies, surfaces, and cells described in the SAT file will be converted to equivalent MCNP objects where available. Where there is no MCNP equivalent, such as for spline surfaces, approximation methods will be developed. The second program will import data from CT and MRI scans. The program will read a sequence of 2D scans in DICOM format. The program will permit the user to select a range of densities in the images and assign a material to that density range. 3D Voxels will be defined from the sequence of 2D scan images. The voxels can be converted to an MCNP lattice or to individual MCNP cells. When individual cells are used, we will develop cell merging algorithms to combine neighboring cells of the same material. The user-friendly software will be designed to require a minimum of user intervention.