回旋加速器是产生高能、强流粒子束的重要方式，具有尺寸小、功耗低、造价低等优点。但回旋加速器同时也存在束流品质低、引出困难等问题，限制了其性能的提高。回旋加速器常用的引出方式如静电引出、磁通道引出、共振引出等均要求较高的束流品质，即束流径向分散小、圈与圈之间有明确的间隙。通常使用的方法有收窄纵向相宽和提高加速电压等几种，有的会降低束流强度，有的会恶化束流品质。本项目借鉴直线加速器中的聚束器原理和环形加速器中的随机冷却原理，提出了一种在回旋加速器上应用的、充分利用加速电场调控束流的方法：通过引入Dee电极精细结构，在束团加速区域产生局部的非均匀电场，使同一束团不同位置的束流获得不同的能量增益，补偿束团能散，提高束流品质和引出效率。本项目有望阐明这一新的束流调控机制，为提高回旋加速器的束流品质和引出效率提供一种新的途径。

Cyclotron is one important way to generate high intensity and high energy beam with advantages of small dimension, low power consumption and economical cost. It also has problems such as poor beam quality and low extraction efficiency. They have limitted the performance of cyclotron. High quality beam with small emittance and large turn separation is requested in all extraction methods. Conventional means including restriction of phase width and raise of acceleration voltage would decrease beam current and deteriorate beam quality. Based on the theories of beam bunch and stochastic cooling, a new modulation method with fine Dee structure is introduced. Individual particles in one beam bunch may gain different energy and compensate the energy dispersion. This new modulation mechanism will be illustrated and a new approach of enhancement of the beam quality and extraction efficiency will be provided in this project.