1、The Lifetime Measurement of First 2+ State in 174Os with LaBr3(Ce),李聪博1,2 等指导教师：吴晓光1，李险峰21中国原子能科学研究院2吉林大学,2012-4-13浙江湖州,CONTENTS,IntroductionLaBr3:Ce Crystals and TestExperimental Electronics and Data analysis methodOff-line Test with 152Eu In-beam ExperimentsConclusions,Introduction,A Large error b
2、ar,Neutron mid-shell,174Os,Os,Introduction,Recoil distance method (RDM) with Plunger devices. (ps - 1ns)Triple- (t) coincidence method using a mix of Ge, plastic, BaF2 or LaBr3(Ce) in decay experiment. (several Ps) H. Mach et al, Nucl. Instrum. Meth. A 280, 49 (1989).3. A new experimental method Tri
3、ple- (t) with LaBr3(Ce) and Ge in-beam experiments. (several Ps),174Os(21+) with lifetime 505(60) ps (RDM).,J. Gascon et al., Nucl. Phys. A 470, 230 (1987).,N. Mrginean, et al., Eur.Phys.J.A 46,329(2010),LaBr3:Ce Crystals and Test,LaBr3:Ce Crystals and Test,CrystalscharacteristicsVolume: Four 30 30m
4、m Three 1 1 inch cylinder,LaBr3:Ce Crystals and Test,Energy Resolution,LaBr3:Ce Crystals and Test,Time Resolution,22Na,Experimental Electronics and Data analysis method,Experimental Electronics and Data analysis method,Sloping method,H. Mach, R.L. Gill and M.Moszyinski, Nucl. Instrum. Meth. A 280, 4
5、9 (1989).,Off-line Test with 152Eu,Off-line Test with 152Eu,Deconvolution Fitting,T1/2=1.42(2)ns,1.39（3）ns,In-beam Experiments,In-beam Experiments,Cascade,In-beam Experiments,Beams: 140 MeV 28SiTarget: 0.9mg/cm2 152Sm rolled onto a12.5mg/cm2 Pb backing 10 HPGe-BGO , 2 Planar HPGe and 7 LaBr3(Ce),In-
6、beam Experiments,J.L. DURELL et al. Phys. Letter. B115 367(1982),In-beam Experiments,508(16)ps,In-beam Experiments,Jing-ye Zhang et al., Phys. Rev. C 73, 037301 (2006),A subshellstructure in the evolution of W and Os isotopic chains.,A large increase,In-beam Experiments,M. Rudigier et al., Nucl. Phy
7、s. A 847, 89 (2010).,In-beam Experiments,N.V. Zamfir et al. Phys. Letter. B357 515(1995),P.Moller,J.R.Nix,W.D.Myers,W.J.Swiatecki,At.DataNucl.DataTables59(1995)185381.,In-beam Experiments,In-beam Experiments,Suggested as +0.117,+0.145,M. Rudigier et al., Nucl. Phys. A 847, 89 (2010).,P.Moller,J.R.Ni
8、x,W.D.Myers,W.J.Swiatecki,At.DataNucl.DataTables59(1995)185381.,Conclusions,The lifetime of the first excited 2+ state in 174Os has been remeasured in fast time experiment and determined to be a greater accuracy, to be 508(16)ps. A deviation of the B(E2) value systematics in 174Os may hint a nuclear structure change, resulting a large increase in hexadecapole deformation (with +0.145).These explanations, from phenomenology at least, modify the expected trends. Other explanations, especially with microscopic model calculations, are needed.,Thanks for your attention!,
