Beam Dynamics In Linear Accelerator Research Articles

2D Node-Based Finite Element Method on Linear Accelerator Cavity for Radiation Therapy

This paper deals with the Electromagnetic (EM) field characterization of an S-band Linear Accelerator (LA) Cavity, which is extensively used in cancer treatment. The analysis of the proposed cavity is carried out using an Eigen-mode full-wave EM solver. Mathematical formulation of cavity parameters using the Finite Element Method up to the system of equations is presented. The EM formulization uses a simple 2D square box as segmentation element and also node-based basis functions are used inside the cavity than the edge-based functions. The proposed numerical analysis of a single cavity of LA system is also applicable for a system with multiple numbers of cavities. The cavity has a resonance of 3.0474 GHz and a Q-factor of 17181.6 with finite conducting boundaries at the ends of the drift tube. The nose cone structure in the cavity is essential to have a stronger E-field at the center where the beam passes. Further, the particle acceleration is not constant along the axis of the cavity, which may have severe consequences for beam dynamics. Proper beam dynamics in LA plays a key role in reducing the mortality rate in cancer therapy applications.

Multicriterial approach to beam dynamics optimization problem

The problem of optimization of particle beam dynamics in accelerating system is considered in the case when control process quality is estimated by several functionals. Multicriterial approach is used. When there are two criteria, compromise curve may be obtained. If the number of criteria is three or more, one can select some criteria to be main and impose the constraints on the remaining criteria. The optimization result is the set of efficient controls; a user has an opportunity to select the most appropriate control among them. The paper presents the results of multicriteria optimization of beam dynamics in linear accelerator LEA-15-M.

An Object-Oriented Parallel Particle-in-Cell Code for Beam Dynamics Simulation in Linear Accelerators

We present an object-oriented three-dimensional parallel particle-in-cell (PIC) code for simulation of beam dynamics in linear accelerators (linacs). An important feature of this code is the use of split-operator methods to integrate single-particle magnetic optics techniques with parallel PIC techniques. By choosing a splitting scheme that separates the self-fields from the complicated externally applied fields, we are able to utilize a large step size and still retain high accuracy. The method employed is symplectic and can be generalized to arbitrarily high order accuracy if desired. A two-dimensional parallel domain decomposition approach is employed within a message-passing programming paradigm along with a dynamic load balancing scheme. Performance tests on an SGI/Cray T3E-900 and an SGI Origin 2000 show good scalability of the object-oriented code. We present, as an example, a simulation of high current beam transport in the accelerator production of tritium (APT) linac design.