Half-life Measurement Of ¹⁷⁵Hf

174Hf have major neutron absorbing cross section,it could be used as a thermal monitoring nuclide in reactor.This function realized by accurate ¹⁷⁵ Hf half life value.But so far,there only have four published half life datas,larger differences against nuclear parameter accurately using and need further study.This paper use a radioactive source of Hf interference the counting rate under different dead time of 177 Lu,get a general relation count rate loss factor f changed along with dead time?t?f?t?=0.042t+0.096.The direct tracking measurement of 181 Hf half life in Hf source tested a obvious regularity—measured fitting half value gradually decrease when occuurence a maximum value with point by point increase mode dispose.Regarding Hf radioactive source as have a high energy gama rays nuclide,and together with 177 Lu proceed half life tracking measurement,obtained a half value of 177 Lu is 6.71 d,this value exceed recommended value and majority measuring result;The disposed half life value through point by point increase mode has a steady increasing trend,While the 181 Hf half life results are consistent with the presence of dead time effect chang law,so in the work of half life measurement,the nuclide which have high energy and long life should take into account firstly,and then with definite method dissolve the interference,Therefore,proceeding source depuration is necessary.Attempte radiochemical separation ¹⁷⁵ Hf source contain impurities employ anion resin and HDEHP resin,it prove that use of HDEHP resin could achieve purification of ¹⁷⁵ Hf source,for obtained ¹⁷⁵ Hf source that contain 65Zn?56Co?and a bit of 52Mn?48Sc?156Tb radioactive contaminants conduct ion exchange use HDEHP resin,under the envoirment condition of different acid and achieved separation about aforementioned impurities.It decontamination factor for 65 Zn and 56 Co respectively reach 5200 and 2360,There only contain less than background levels 65 Zn in gained source after seprartion,and achieved radioactive pure ¹⁷⁵ Hf radioisotope.Eventually use well type HPGe under the smaller the dead time?<1%?,about full spectrum area(including all characteristics of ? rays total energy peak of ¹⁷⁵ Hf and all-around Compton scattering background,natural background/all-around peak and Compton background of impurity nuclide)take advantage of a means of tracking measurement and use coaxial HPGe under the fixed position of supervision source together with ¹⁷⁵ Hf,performed lengthen out to 30 d and 40 d tracking measurement,obtained half life values is 70.64±0.15 d and 70.73±0.25 d respectively.With relevant respection,there has no obvious systemic error.The results compared with the previous results,it degrees of freedom has greatly increased,the uncertainty of half life is controlled in small range.