“三截面法”或“三梯度法”测量发射度的条件

THE CONDITIONS OF EMITTANCE MEASUREMENT BY MEANS OF “THREE BEAM WIDTH METHOD” OR “THREE FIELD GRADIENT METHOD”

一、基本原理'三截面法'或'三梯度法'是一种非阻栏式、间接测量方法。它适用于高能束和实时监察束性能,但测量误差较大。图1表示了典型的用'三截面法'测量束发射度的元件安排。在束线的三个位置 A,B,C 上测出束截面半宽度,即束包络 W_A,W_B,W_C,然后根据束流输运方程解出束发射度参数。

The error sources,error estimation,and the methods of decreasing the errors about beam emittance measurement by means of 'Three Beam Width Method' or 'Three Field Gradient Method' are discussed.