-------------- The stress put on built-in generalised scoring options is another aspect of FLUKA "philosophy" which differentiates it from many other programs where users are supposed to write their own ad-hoc scoring routines for each problem. This characteristics, which was already typical of the old Ranft codes, has allowed to develop in the modern FLUKA some rather sophisticated scoring algorithms that would have been too complex for a generic user to program. For instance the "track-length apportioning" technique, introduced in 1990 by Fasso` and Ferrari, used in dose and fluence binning, which computes the exact length of segment travelled by the particle in each bin of a geometry independent grid. This technique ensures fast convergence even when the scoring mesh is much smaller than the charged particle step. Different kinds of fluence estimators (track-length, collision, boundary crossing) were implemented in 1990-1992, replacing the corresponding old ones. The dimension limitations (number of energy intervals) were removed and replaced by a much larger flexibility due to dynamical memory allocation. Scoring as a function of angle with respect to the normal to a surface at the point of crossing was also introduced. Facilities were made available to score event by event energy deposition and coincidences or anti-coincidences between energy deposition signals in different regions, and to study fluctuations between different particle histories. The pre-existent option to write a collision file was completely re-written and adapted to the more extended capabilities of the new code. In 1991, time gates became applicable to most scoring facilities, allowing to ignore delayed radiation components such as multiply scattered low energy neutrons. In 1994, two new options were added: residual nuclei scoring and scoring of particle yields as a function of angle with respect to a fixed direction. In the latter case, several new quantities can be scored, such as rapidity, various kinematical quantities in the lab and in the centre-of-mass frame, Feynman-x etc. In 2005, the possibility to follow on-line the radiation from unstable residual nuclei has been implemented, together with an exact analytical calculation (Bateman equations) of activity evolution during irradiation an cooling down. As a consequence, results for production of residuals and their effects as a function of time can be performed in the same run.
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