中文摘要：

根据对高斯源的检验，引入两个π介子相对距离的均方根半径Rrmst来表示高能重离子碰撞中π介子发射源的空间尺寸。利用imaging计算方法可以不依赖于源模型计算出相对距离的均方根半径。对Core—Halo模型进行计算并与高斯拟合结果比较，结果显示，由于长寿命共振态衰变产生的π介子的贡献，半径Rrmst显示出较大的π介子发射空间。另外，对于π介子为混沌发射的情况，通过imaging方法计算得到的π介子发射源的混沌性参量明显大于高斯拟合所得到的结果。

英文摘要：

We characterize the spatial dimension of pion-emitting source in high-energy heavy ion collisions with the radius of root-mean-squared of two-pion relative-distance R Based on the imaging technique, one can calculate Rrmst model-independently, Applying this method to the Core-Halo model and comparing the results with that of Gaussian fitted, the results indicate that due to the effects of long-lived resonance decay, the values of Rrmst show a larger spatial size of pion-emitting region. Meanwhile, for the chaotic source the chaoticity factors calculated by imaging technique are larger than that of Gaussian fitted.