基于大科学装置冷却储存环等时质量谱仪，测量78Kr碎片53Co和53Fe相同纵向动量下的J=19/2同质异能态和基态的产额比。本项目测量核处于全剥离状态，不同于将碎片植入靶中的测量方法，其能有效的屏蔽同质异能态内转换衰变道，从而得到更准确的同质异能态和基态产额比。利用实验测量的镜像核产额比，可以检验基于AA模型的碎片角动量分布理论的一个重要假设：蒸发过程中，质子和中子带走的角动量相同，且可忽略，从而理解长期以来理论预言的产额比和实验结果不一致的原因。

The isomeric ratio values for mirror nuclides 53Co and 53Fe will be measured using isochronous mass spectrometry at CSR. Measurement of isomeric ratio with isochronous mass spectrometry is different from traditional method which measures gamma decay of atom. Since the nuclide is bare, the internal conversion of isomer is forbidden and more accurate ratio can be obtained.With the experimental isomeric ratios, an assumption of the AA model, the evaporation of protons and neutrons is in equilibrium and angular momentum carried away can be neglected, can be tested. This will help us to understand the reason that theoretical predictions are not consistent with exprimental isomeric ratios.