After annealing at 600 , because of formation of multi - vacancy - type defects that have long positron lifetime , positron annihilation average lifetime increased . when the average positron lifetime increased to maximum value ( 360ps ) , the interstitial oxygen concentration decreased to minimum value ( 4 1017atoms / cm3 ) . this result suggested that oxygen was involved in the formation of multi - vacancy - type defects 正电子湮没技术测试证明，快中子辐照直拉硅中在大约600退火时产生的多空位缺陷具有较长正电子寿命，可以使正电子平均寿命增加，当样品的正电子平均寿命达到最大时( 360ps ) ，其间隙氧含量降到一个极小值( 4 10 ~ ( 17 ) atoms / cm ~ 3 ) ，这说明氧参与了这些缺陷的形成。
