Measurement of the branching ratio related to the internal pair production of Y-90
Measurement of the branching ratio related to the internal pair production of Y-90
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DOI：
10.1016/j.apradiso.2019.108942
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发表时间：
2020-02-01
影响因子：
1.6
通讯作者：
Solc, Jaroslav
中科院分区：
文献类型：
--
作者：
Dryak, Pavel;Solc, Jaroslav
这项工作的目的是确定在 Y-90 衰变时 Zr-90 核的 1760.7 keV 能级和基能级之间的 E0 跃迁中产生的正电子对的数量。转换次数由源自正电子湮灭的 511 keV 光子数量确定，并针对飞行中的正电子湮灭进行了校正。湮灭光子的发射由两个校准的高纯锗探测器上 511 keV 全能峰值的测量确定。测量是使用两个不同结构的源进行的。第一个来源是充满 Sr-90 溶液（与 Y-90 平衡）的 1 ml 安瓿，插入铝吸收器中，活性为 38.041 MBq。另一个来源是聚乙烯吸收器中 Sr-90 溶液（与 Y-90 平衡）的蒸发残留物。在这两种情况下，源材料中都发生了正电子湮灭。 511 keV光子探测效率通过蒙特卡罗计算确定，其中源被定义为理论连续正电子谱，最大能量为738 keV。与Y-90衰变过程中内部对产生相关的支化比被确定为(3.26+/-0.04)×10(-5)对/衰变。
The aim of the work is to determine the number of positron-electron pair creation in the E0 transition between the 1760.7 keV level and the ground level of the Zr-90 nucleus at the Y-90 decay. The number of conversions is determined from the number of 511 keV photons originating from positron annihilation corrected for the annihilation of positrons in flight.Emission of annihilation photons was determined from the measurements of 511 keV full-energy peak on two calibrated high-purity germanium detectors. The measurements were performed with two sources of a different construction. The first source was a 1 ml ampoule filled with Sr-90 solution (in equilibrium with Y-90) with an activity of 38.041 MBq inserted into an aluminum absorber. The other source was the evaporation residue of the Sr-90 solution (in equilibrium with Y-90) in a polyethylene absorber. In both cases, the annihilation of positrons occurred in the source materials. The efficiency of 511 keV photon detection was determined by Monte Carlo calculation, where the source was defined as a theoretical continuous positron spectrum with a maximum energy of 738 keV. The branching ratio related to the internal pair production during Y-90 decay was determined to be (3.26 +/- 0.04) x 10(-5) pairs/decay.