The SHIELD11 Computer Code

SHIELD11 is a computer code for performing shielding analyses around a high-energy electron accelerator. It makes use of simple analytic expressions for the production and attenuation of photons and neutrons resulting from electron beams striking thick targets, such as dumps, stoppers, collimators, and other beam devices. The formulae in SHIELD11 are somewhat unpretentious in that they are based on the extrapolation (scaling) of experimental data using rather simple physics ideas. Because these scaling methods have only been tested over a rather limited set of conditions--namely, 1-15 GeV electrons striking 10-20 radiation lengths of iron--a certain amount of care and judgment must be exercised whenever SHIELD11 is used. Nevertheless, for many years these scaling methods have been applied rather successfully to a large variety of problems at SLAC, as well as at other laboratories throughout the world, and the SHIELD11 code has been found to be a fast and convenient tool. In this paper we present, without extensive theoretical justification or experimental verification, the five-component model on which the SHIELD11 code is based. Our intent is to demonstrate how to use the code by means of a few simple examples. References are provided that are considered to be essential for amore » full understanding of the model. The code itself contains many comments to provide some guidance for the informed user, who may wish to improve on the model.« less