spontaneous fission counting

例句：

1. 1.This method is used to count the number of spontaneous fission events in a sample.
   这种方法用于计算样本中自发分裂事件的数量。
2. 2. The researcher found that the spontaneous fission rate increased with temperature.
   研究者发现，自发分裂率随着温度的升高而增加。
3. 3. The team was tasked with counting the number of spontaneous fission events in the sample.
   该团队被分配了统计样本中自发分裂事件数量的任务。