Improvements to the Integrated TIGER Series Monte Carlo radiation transport codes

This paper describes two areas in which the usability of the Integrated TIGER Series (ITS) Monte Carlo radiation transport codes has been improved for use in the design and analysis of tests conducted with the DECADE nuclear weapons effects simulator. The first area is in improving the speed of execution. By benchmarking and profiling the member codes of the ITS on three representative test cases (1-D, 2-D and 3-D geometry), computationally intensive subroutines were identified. The algorithms in these routines were replaced with numerically identical, but more efficient methods and the subroutines recoded in the original FORTRAN 77 higher-level language to accelerate code execution. Timing results of the modified codes indicate that a speedup factor of 2 was achieved in nearly all cases. The second area is in the development of a graphical user interface (GUI) to facilitate parameter input and input file development. A proof-of-concept GUI has been written for use on PC-based DOS/Windows platforms that allows the user to easily define problems for the ITS. A mouse and/or arrow-key driven interface can be used to move through a series of menus for each set of ITS input options, with colored graphics display of the geometric configuration providing visualization for the user. Currently restricted to the XGEN, TIGER and CYLTRAN member codes, this GUI has already proven useful in facilitating the writing of input files and reducing inadvertent errors.