The properties of pygmy dipole states in 208Pb were investigated using the 208Pb(17O, 17O'γ) reaction at 340 MeV and measuring the γ decay with high resolution with the AGATA demonstrator array. ...Cross sections and angular distributions of the emitted γ rays and of the scattered particles were measured. The results are compared with (γ, γ') and (p, p') data. The data analysis with the distorted wave Born approximation approach gives a good description of the elastic scattering and of the inelastic excitation of the 2+ and 3- states. For the dipole transitions a form factor obtained by folding a microscopically calculated transition density was used for the first time. This has allowed us to extract the isoscalar component of the 1- excited states from 4 to 8 MeV.
We have studied energy levels in Fe-63 populated in the beta-decay of Mn-63. A new (preliminary) level scheme of Fe-63 includes 10 excited states connected by 21 gamma-rays. The first excited states ...at 357 and 451 keV have the level half-lives of 110 ps and 780 ps, respectively. Three states, at 357, 451, and 1132 keV, are strongly beta-fed with log ft similar to 5, while there is only a very week beta-feeding, if any at all, to the ground state. The new results imply that Fe-63 departs from a simple shell model structure observed for heavier N = 37 isotones of Ni-65 and Zn-67.
Lifetime measurement in 195Po Grahn, T.; Dewald, A.; Greenlees, P. T. ...
European physical journal. A, Hadrons and nuclei,
3/2009, Letnik:
39, Številka:
3
Journal Article
Recenzirano
Odprti dostop
The lifetime of the 17/2
+
yrast state in
195
Po has been measured using the recoil distance Doppler-shift technique to be
= 43(11) ps. The lifetime was extracted from the singles
-ray spectra ...obtained by using the recoil-decay tagging method. The present work provides more information of the coupling schemes, shapes and configuration mixing in neutron-deficient odd-mass Po nuclei.
Lifetime measurement of the 167.1 keV state in {sup 41}Ar White, E. R.; Mach, H.; Department of Nuclear and Particle Physics, Uppsala University, Post Office Box 535, S-75121 Uppsala ...
Physical review. C, Nuclear physics,
11/2007, Letnik:
76, Številka:
5
Journal Article
The Advanced-Time-Delayed method was used to measure lifetimes of the states in {sup 41}Ar populated in the {beta} decay of {sup 41}Cl. The nuclei {sup 41}Cl were produced at ISOLDE by 1.4-GeV proton ...bombardment of a thick UC{sub x} target and mass-separated as molecular ions, XeCl{sup +}. Our measured half-life of the 167.1-keV state, T{sub 1/2}=315(15) ps, is significantly lower than the previously measured value of 410(30) ps. We have also determined T{sub 1/2}=260(80) ps and T{sub 1/2}{<=}46 ps for the 515.9- and 1867.7-keV states, respectively. These are the shortest lifetimes measured so far with the ultrafast timing method using the new LaBr{sub 3}(Ce) crystals for {gamma}-ray detection.
Recently, a method for the identification of multiphonon states in vibrational nuclei was successfully developed. A survey was performed and it was found, surprisingly, that the energies of the first ...2
+ states are systematically low by about 15% with respect to the values expected from the global nuclear properties. This appears to be in contradiction with the general belief that these states have a high purity. It can be questioned whether such results are not simply an artefact due to the weights used in the fits. One way to answer this question is to compare the experimental results with the predictions of the Brink model. To this end, the equations for four and five phonons were explicitly calculated. It will be shown that the predictions are quite good, provided the one phonon energy be renormalized, i.e. increased by about 15%. Since the uodified Brink method involves only the use of a “virtual” 2
1
+ energy and no level fit, a problem of weights cannot be invoked. Possible explanations of the anomaly are examined.
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