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[en] We report on beams of aligned Lithium nuclei as a tool in nuclear physics. The production of these beams is described. Their usefulness to obtain information on the deformation of 7Li is discussed. (orig.)
[en] A lifetime measurement of the excited states in the neutron-rich isotope 13B has been performed using the 7Li(7Li,p)13B reaction. An anomalously long mean lifetime of 1.3(3) ps was found for the excited state at 3.53 MeV, giving the upper limits of the transition strengths to the ground state: B(M1)=7.2x10-4 Weisskopf unit (W.u.) and B(E2)=0.81 W.u.. The hindered transition strengths indicate significant intruder configurations for the excited state, coexisting with the normal ground state. The data are well explained by recent shell-model calculations, which suggest Jπ=3/2- for the 3.53-MeV state with the dominant intruder (ν2p2h) configuration.
[en] The present work reports heavy-ion-assisted production of 93mMo from a natural yttrium target using the 89Y(7Li, 3n)93mMo reaction. Three different methodologies based on liquid-liquid extraction (LLX), aqueous biphasic extraction and precipitation, have been developed for separation and extraction of no-carrier-added (nca) 93mMo (T1/2=6.85 h) radionuclide from bulk yttrium target. Complete separation of nca Mo from the target Y has been achieved by employing LLX technique with 0.1 M trioctylamine (TOA) dissolved in cyclohexane and 8 M HCl. Quantitative separation of 93mMo from the yttrium target is also possible by precipitating bulk yttrium with 1 M oxalic acid. However, for this particular case, studies have shown that the aqueous biphasic extraction is not the method of choice for separation of nca Mo. Nevertheless, the extraction pattern is important in the context of simulation experiments for studying the behaviour of 106Sg. Similarity or dissimilarity between the extraction patterns in various analytical systems will be helpful to decisively place Sg in the right position in the periodic table
[en] The rate for destruction of 7Li via deuteron-induced reactions is reexamined and is found to be appreciably larger than that previously used in primordial nucleosynthesis codes over most of the temperature region of interest. Numerous calculations were run to determine the significance of the new rate; it was found to change the predicted 7Li abundance by not more than 20% over the parameter space examined
[en] A multi-moderator spectrometer which involves a pair of 6Li and 7Li glass scintillators has been developed as a new type neutron spectrometer which can measure neutron spectra in mixed fields of neutrons, charged particles and gamma-rays realizing in space. The discrimination of neutrons from other particles can be done by subtracting the light outputs of 7Li glass scintillator from those of 6Li glass scintillator, since these two light outputs are almost equal for charged-particle and gamma-ray events. The moderator thicknesses are 1.5, 3.0, 5.0 and 9.0 cm. The response functions with and without each moderator thickness were calculated in the energy range of 10 -6 to 150 MeV by using the MCNP-4B2 Monte Carlo code. For comparison, they were also measured at 0.25, 0.55, 1.0, 5.0 and 22 MeV neutrons in the mono-energetic neutron fields at the Fast Neutron Laboratory (FNL) and the Cyclotron and Radioisotope Center (CYRIC) of Tohoku University. In order to investigate the characteristics of the spectrometer, two kinds of experiments were performed. The first was performed in a neutron and gamma-ray mixed field using a 60Co gamma-ray source and 252Cf neutron source. The other was in neutron and proton mixed fields which were produced by bombarding a 2 mm thick Li or Be target with 35 and 70 MeV protons from cyclotrons at CYRIC and National Institute of Radiological Sciences, respectively. The experiments gave evidence that this spectrometer has a sufficient ability to measure neutron spectra in mixed fields by discriminating neutrons from gamma rays and protons. (author)