Focusing System With Permanent Magnets for Klystrons
Applying permanent magnet technology to beam focusing in klystrons can reduce power consumption and increase reliability. These features benefit a variety of applications especially for large facilities that use a large number of klystrons such as the International Linear Collider. The low magnetic field needed for the purpose allows us to use inexpensive ferrite magnets instead of rare earth magnets. In order to evaluate the feasibility of such a focusing system with ferrite magnets, a test model for 750 kW L-band klystron was constructed. As a result of the power test, we attained 94% of the output power compared to an electromagnet.
Distributed RF Scheme (DRFS) - Newly Proposed HLRF Scheme for ILC
The Baseline Conceptual Design (BCD) of the superconducting ILC main linac (ML) assumes 2 tunnels and the reference design report (RDR) based on that. However due to the high cost of construction, a single tunnel proposal has been developed. Two supporting plans, the klystron cluster scheme (KCS) and the distributed RF scheme (DRFS) are under intensive study by the ILC global design effort (GDE). In this report, we present the details of the DRFS configuration. We also discuss the availability and a maintenance plan. Critical items and the demonstration plan for the DRFS are also described.
Survey of numerical methods in field calculations
In magnetic field computations, Maxwell's equations are often restricted to the Poisson equation. Several approaches to solving this type of equations are discussed together with the possible field defining potentials. Finite element and finite difference methods are compared, as are the numerical means available for solving the corresponding large systems of matrix equations. Successive overrelaxation, conjugate gradient and preconditioned conjugate gradient method are frequently applied. The integral equation method avoids limitations due to boundary conditions but has other inconveniences due to the fully occupied matrix equation which has to be solved. After mentioning the boundary integral method and techniques to tackle eddy current problems, some examples of proven computer codes for the numerical field calculation are briefly described.