Speaker
Description
TRIUMF hosts several high-power accelerators -- including the 500 MeV cyclotron and the 30 MeV electron linac --, a variety of primary and secondary beamlines, and rare ion beams post accelerators. The computer programs that we use to simulate the beam dynamics in these machines can be grouped into two categories, depending on whether they use a 'detailed' or a 'reduced' beam physics model. Under the 'detailed' category we make extensive use of the particle-in-cell codes ASTRA, OPAL-CYC, and WARP.
But the work-horse of beam physics at TRIUMF is the 'reduced' code TRANSOPTR, which instead of calculating the trajectories of a large number of macro-particles, tracks directly the 21 statistical second moments of the beam distribution. I will present a brief overview of this code, and show examples of applications.
In many high intensity cases, a purely second-moment code such as TRANSOPTR is incapable of giving the detail needed to predict and control losses. For these more complicated cases, where 'detailed codes' work but are orders of magnitude slower to run, we are developing hybrid models, which combines features of both 'reduced' and 'detailed' models. We recently successfully implemented and tested such a code, which represents the beam using macro-particles containing discrete longitudinal coordinates but transverse second moments. I will explain this approach in detail, and discuss our plans to continue developing such codes that can be tuned to track exactly the physics one is interested in, and no more than that, achieving optimum computer efficiency and execution speed.
I will also touch upon the topics of the symplecticity of such codes.
