But the positive electrons produced by aluminium under the action of a source of alpha rays continue to be emitted for some time after removal of the source. The number of electrons emitted decreases by half in three minutes.

• 但是，在射线动能源作用下铝产生的正电子在动能源撤走后的相当长时间里仍继续被排斥出来，且排出的电子数量在3分钟后减少一半。