上海光源储存环新注入方式

Study of new injection schemes for the SSRF storage ring

上海光源储存环的新工作模式和新装插入件会导致动力学孔径和注入效率的减小,传统的注入方式不再满足恒流注入要求。分别从改变注入方式和减小注入束流发射度两个角度解决注入对动力学孔径的需求。脉冲多极铁与凸轨相结合的注入方式可以将动力学孔径的要求降低到7 mm以下。利用斜四极铁在高能输运线上进行水平和垂直发射度互换可以将注入束流发射度降低到近1/10而降低注入点的束斑尺寸。两者都可以将注入效率提高到95%以上。二者在更小动力学孔径的情况下同时使用还可以减小脉冲多极铁的强度。

Background： Several new operation modes were designed and commissioned in Shanghai synchrotron radiation facility （SSRF）, and these new modes and insertion devices reduced the dynamic aperture and the injection efficiency of the storage ring. Purpose： This study aims to improve the injection efficiency of SSRF store ring. Methods： A new injection scheme employing multipole magnet and injection emittance reducing at the high energy transport line have been studied, Results： Pulsed multipole magnet with orbit bump reduced the dynamic aperture to less than 7 mm. Emittance exchange, by installing skew quadrupoles at the high energy transport line, scaled-down the horizontal emittance by an order, and then reduce the injection beam size. Both methods can increase the injection efficiency to higher than 95%. Conclusion： The new injection scheme with emittance reduction showed efficiency to improve the injection. The two methods also can work together to reduce the strength of pulsed multipole magnet or for smaller dynamic aperture.