Positron Decays of 42 Ti and 38 Ca
Positron Decays of 42 Ti and 38 Ca
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42 Ti 和 38 Ca 的正电子衰变
DOI：
10.1103/physrev.186.1160
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发表时间：
1969
期刊：
影响因子：
--
通讯作者：
E. Jacobs
中科院分区：
文献类型：
--
作者：
A. Gallmann;E. Aslanides;F. Jundt;E. Jacobs
用Ca 40（h，n）反应研究了Ti 42的正电子衰变.一个强的610.7±0.5 keV γ射线（半衰期T12 = 0.202±0.005秒）是由Sc 42的611 keV能级的正电子分支产生的。观测到2222±2 keV的弱γ射线，对应于Sc 42的2223 keV能级的正电子分支。利用测得的半衰期和β衰变能，从β衰变系统学计算出分支比为r β 0+=（44.1±1. 2）%，r β 1+=（55.2±1. r β 9+=（0. 7 ±0. 2）%。3）%。log ft值3.179±0.015和4.36− 0.24+ 0.16确定Sc 42的611和2223 keV态的J π= 1+。用Ar 36（h，n）反应研究了Ca 38的正电子衰变.已测量到该衰变的半衰期为0.439±0.012 sec。除了供给K38的1695 keV能级的强Gamow-Teller跃迁外，还观测到一条3210±2 keV的弱γ射线线，初步认为这是由Ca 38的（0.6±0.2）% β+分支供给的K38的3337 keV能级的跃迁。它的log ft（3.90− 0.13+ 0.10）则建立了这个态的J π= 1+赋值。
The positron decay of Ti 42 has been investigated using the Ca 40 (h, n) reaction with a natural calcium target. A strong 610.7±0.5-keV γ ray with a half-life T 1 2= 0.202±0.005 sec is attributed to a positron branch to the 611-keV level of Sc 42. A weak 2222±2-keV γ ray has been observed, which corresponds to a positron branch to the 2223-keV level of Sc 42. Using this measured half-life and the β-decay energies, the branching ratios are calculated from β-decay systematics to be r β 0+=(44.1±1. 2)%, r β 1+=(55.2±1. 2)%, and r β 9+=(0.7±0. 3)%. The log ft values 3.179±0.015 and 4.36− 0.24+ 0.16 establish J π= 1+ for both the 611-and the 2223-keV states of Sc 42. The positron decay of Ca 38 has been investigated using the Ar 36 (h, n) reaction. The half-life 0.439±0.012 sec has been measured for this decay. In addition to the strong Gamow-Teller transition feeding the 1695-keV level of K 38, a weak 3210±2-keV γ-ray line has been observed which is tentatively attributed to a transition from the 3337-keV level in K 38 fed by a (0.6±0.2)% β+ branch of Ca 38. Its log ft (3.90− 0.13+ 0.10) then establishes the J π= 1+ assignment for this state.