6. TYPICAL RUNNING TIME
The following sample problems were run on a CDC 6600.
i) A calculation of the angle-energy distribution of an 8 MeV electron beam as it penetrates a slab of aluminium, using a P24 Goudsmit-Sanderson distribution, 2 per cent energy loss per path length segment, and following 3000 histories required 15 minutes.
ii) About 5 minutes were required to calculate the energy deposition profile for a beam of 2 MeV electrons normally incident on a semi-infinite slab of aluminium or lead. A Gaussian angular straggling model was used, with 2 per cent energy loss steps, and 500 histories were followed.
iii) A source of 10 MeV electrons, normally incident at one end of a system of concentric cylinders of aluminium, iron and tungsten with a central void was set up. Each cylinder was divided into 25 regions. The energy deposition distribution was calculated using 5 per cent energy loss steps, and following 256 histories Less than 2 minutes were required for a no-field case, 10 minutes were required with a 100,000 gauss uniform axial magnetic field.
iv) A time-dependent energy deposition calculation on a lucite cylinder require 7 minutes for 10 time steps. The electron source was normally incident and uniformly distributed on the end of the cylinder which was divided into 5 radial and 20 axial segments. 64 electron histories were followed per time step.