资 源 简 介
Neutron acceptance diagram shading is a ridiculously fast way of modelling neutron beams. Acceptance diagram shading is inspired by polygon-based techniques in computer graphics and receives approximately the same kind of speed gain relative to monte-carlo (ray tracing), i.e. hours can become milliseconds.
It"s based on the work of Jack Carpenter, John Copley, David Mildner and Leo Cussen (amongst others), but takes things one stage further by subdividing phase space into triangular partitions and adding an extra dimension: statistical weight. This means that you can modularise the beam calculation and compare the results quantitatively with a ray-tracing simulation.
Limitations:
1. It"s strictly monochromatic (but you can get away with a 15% spread typical of velocity selectors)
2. Your instrument must have independent horizontal and vertical planes. No crosstalk.
3. Polarisation and time-of-flight are further complications that you have to consider manually.
