利用电压异步调节束流能散度

对直线感应加速器加速电压的同步性对束流能散度的影响进行了分析，结果表明:考虑束流负载效应后，束流的不同部分将得到不同的能量增益，前后沿部分相对于平顶部分得到更多的能量增益，从而在一定程度上增加整个束流的能散度，限制了加速器光源尺寸的进一步减小。因此，提出利用调节加速电压异步的方法来调节束流不同部分得到的能量增益，从而在一定程度上降低整个束流脉宽期间的能散度。初步的试验结果也证明，加速电压的异步调节可以明显改变束流整体的的能散度。

Beam-energy-spread adjustment using cell-timing asynchronization

The pulsed high-current beams in Linear Induction Accelerator required by radiography gain their energy from the induction electric field generated at the acceleration gap. Beam loading effect determines that particles at different longitudinal position within a bunch get unequal gain of energy: particles at the beam head and tail have their energy increase faster than those at the main part, which consequently results in an energy spread increase. Since the first observations, significant efforts have been made to measure and restrain this energy spread growth. In this paper, a new method is proposed to mitigate the energy spread growth through regulating the energy gain of particles within a bunch by cell-timing asynchronization. Initial results from experiments on the accelerator show that the beam energy spread can be effectively controlled with this method.