The X-ray and electron benchmarking of the Monte Carlo codes MCNP-4A and 4B on different computers

MCNP (Monte Carlo N-Particle) is a Monte Carlo transport code which has been of widespread use in modelling the dosimetry of ionizing radiations. The most recent version (4B) features improved electron transport compared with the previous version 4A. The processing time required by a number of computing systems to carry out X-ray and electron transport calculations using both versions of the code was compared. Version 4A was installed onto a Dec Alpha Server 8200, a personal computer (Pentium 90 MHz), and a Sun Sparc20, 10, 4 and 1+. MCNP-4B was also installed onto the Sun Sparc20. The benchmark tests consisted of determining the transmission of 2 MeV X-rays and 30 MeV electrons through lead. It was found that the Dec Alpha Server 8200 was the fastest computing platform, and the Sun Sparc1+ was the slowest for both tests. The difference in computational speed between different platforms was not matched by the corresponding differences in price. The time required by version 4B to complete the X-ray and electron benchmark tests was found to be 1.4 and 2.3 times greater than version 4A, respectively, without any difference in the results of the calculation for each type of radiation. This suggests that in cases where computing time is important, it may be preferable to use version 4A instead of 4B.