~(175)Hf的半衰期测量
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摘要
~(175)Hf现有的半衰期数据偏少且分歧较大,对核参数的准确使用不利。本实验通过加速器质子束流轰击~(175)Lu,并使用HDEHP萃淋树脂进行离子交换,得到无载体无~(181)Hf干扰的高纯度~(175)Hf液体测量源,对其中的杂质~(65)Zn与~(56)Co的去污因子分别为5.2×10~3与2.3×10~3;引入一固定位置的监督源~(137)Cs与~(175)Hf进行了40d的连续测量,对343keV以及661keVγ射线计数率的比值关于测量时间进行线性拟合,得到~(175)Hf的半衰期为(70.73±0.25)d,并对测量结果进行了相关检验。
The existing data of ~(175)Hf half-life are few and have large differences,which is unfavorable to use nuclear parameters accurately.In this experiment,~(175)Lu was bombarded by accelerator proton beam and purified by HDEHP extraction leaching resin.Then high purity ~(175)Hf was obtained,which is free carrier and no interference of ~(181)Hf.Decontamination factors for ~(65)Zn and ~(56)Co respectively are 5.2×10~3 and 2.3×10~3.~(137)Cs,as a supervision source,was measured lasting 40 days with ~(175)Hf.The half-life value of ~(175)Hf is(70.73±0.25)d obtained by fitting the relation between the ratio of 343 keV and 661 keV γ-ray counting rate and time.
The existing data of ~(175)Hf half-life are few and have large differences,which is unfavorable to use nuclear parameters accurately.In this experiment,~(175)Lu was bombarded by accelerator proton beam and purified by HDEHP extraction leaching resin.Then high purity ~(175)Hf was obtained,which is free carrier and no interference of ~(181)Hf.Decontamination factors for ~(65)Zn and ~(56)Co respectively are 5.2×10~3 and 2.3×10~3.~(137)Cs,as a supervision source,was measured lasting 40 days with ~(175)Hf.The half-life value of ~(175)Hf is(70.73±0.25)d obtained by fitting the relation between the ratio of 343 keV and 661 keV γ-ray counting rate and time.
引文
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[10]Han J,Lee K B,Park T S,et al.18F half-life measurement using a high-purity germanium detector[J].Appl Radiat Isot,2012,70(11):2581-2585.
[2]Wilkinson G,Hicks H G.175 Hf,a new radioactivive isotope hafnium[J].Phys Rev,1949,75(4):696-698.
[3]Rao C L,Yaffe L.Nuclear reactions induced in tantalum by protons of energy up to 84MeV[J].Can J Chem,1963,41(10):2516-2532.
[4]Popov Y S,Zakharova L V,Markushin M N,et al.Decay of 175 Hf and 181 Hf[J].Radiochemistry,2001,43(6):481-484.
[5]Fang K H,Wang D W,Yang S B,et al.Half life of175 Hf[J].Appl Radiat Isot,2012,70:2328-2331.
[6]周丰群,杨景康,拓飞,等.HPGe-γ谱仪死时间校正方法的实验研究[J].高能物理与核物理,2005,29(12):1175-1178.
[7]秦建国,赖财锋,张信威,等.高强度短寿命核素对其他峰计数率和半衰期影响的研究[J].核电子学与探测技术,2013,33(4):442-446.
[8]PomméS.Problems with the uncertainty budget of half-life measurements[J].ACS Symposium,2007:945.
[9]张小林,王世联,凡金龙,等.101 Mo半衰期的测定[J].核电子学与探测技术,2006,26(6):893-895.
[10]Han J,Lee K B,Park T S,et al.18F half-life measurement using a high-purity germanium detector[J].Appl Radiat Isot,2012,70(11):2581-2585.