Optimization of Cooling System of Linac Collinear Load

Collinear load, coating with microwave-absorbing material, determined to linear accelerator (LINAC) to absorb the remnant power. It forms a part of actual accelerating structure and substitutes for traditional waveguide-type load to make the accelerating structure compacter and size smaller. In order to guarantee operational reliability, it is necessary to keep the operation frequency of cavities of the collinear load at 2856MHz and at a small shift. An approach utilized to accurately evaluate the frequency change caused by non-uniform thermal deformation is presented and a strategy for optimizing its cooling system is also described simultaneously. A six-cavity collinear load, coated with FeSiAl alloy, is researched. The results show that the frequency shift of cavities of the collinear load can be controlled within -56 similar to 35kHz, when it runs on 2856MHz and 2 pi/3 mode and the structure of its cooling system becomes much more compact and economic.