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1.
The influence of high concentrations of the Na+ impurity on the photo and thermostimulated luminescence in an xirradiated KBr crystal has been studied. It is revealed that at an impurity concentration of 1 mol.% the absorption spectrum of the KBr:Na crystal possesses only the bands belonging to the (, I A) and (F, H A) pairs of the centers and that the thermoluminescence spectrum consists of two peaks with a maximum at 140 and 165 K.  相似文献   

2.
The 84Se nucleus has been produced as fission fragment in the fusion reaction 18O + 208Pb at 85MeV bombarding energy and studied with the Euroball IV array. Medium-spin states of this neutron-rich isotope have been identified for the first time. Its level scheme has been obtained up to 4.9MeV excitation energy and spin I 7. Its structure is interpreted by analogy with those of the stable heavier isotones. The evolution of the energy of the N = 50 neutron-core excitation is discussed as a function of the proton number.  相似文献   

3.
The synergistic effects of NH3 ambient and ultraviolet illumination on the dielectric properties of hafnia based gate dielectrics are reported in this paper. The films were processed at relatively low temperatures (∼400 °C) by pulsed laser ablation and UV oxidation technique. UV illumination and the NH3 ambient created a thin and a denser interfacial layer (at the film-Si interface) comprised of HfSiON bonding. As a result of the interfacial layer modification, a leakage current density lower than 10−4 A/cm2 and a dielectric constant of ∼21.7 were extracted from the best samples processed in NH3 and under UV illumination. The nitrogen doped HfO2 also exhibited a thinner interfacial layer (∼12 Å) in comparison to the films processed without NH3 ambient.  相似文献   

4.
The EC decay of 236Am has been studied using a gas-jet coupled on-line isotope separator. A half-life analysis revealed that there are two EC-decaying states in 236Am: the 5- state with T1/2 = 3.6(2) min and the (1-) state with T1/2 = 2.9(2) min. The 1185.5 keV level in 236Pu was found to be the K isomer with K = 5- and t1/2 = 1.2(3) s. EC transitions from 236g, mAm to the 1185.5, 1311.5, and 1340.8 keV levels in 236Pu show small log ft values of 4.9, 5.3, and 4.8, respectively, indicating that the 5/2+[642] 5/2+[633] transition largely contributes to these transitions, and thus, the populated levels should be the 5/2-[523]5/2+[642] two-quasiparticle states. The K = 0- octupole band established in 236Pu is located at higher energy than those in 238,240Pu, which implies that the octupole correlations become weak at 236Pu.  相似文献   

5.
The --decay of 147Cs to 147Ba has been studied by means of - and X-ray spectroscopy. A new level scheme of 147Ba is significantly modified and extended in comparison to the one previously reported. The Advanced Time-Delayed (t) method has been applied to measure half-lives of the 46.2 and 85.4 keV levels in 147Ba yielding T1/2 of 510(80) ps and 370(100) ps, respectively. The lifetime results combined with the deduced internal conversion coefficients allowed to assign M1 multipolarity to three transitions. The B(M1) values obtained for the 39.2, 46.2 and 85.4 keV transitions range from 0.017 to 0.043 W.u. and represent typical B(M1) strength in the Ba-Er region. Model calculations using a shell correction approach with the axially deformed Woods-Saxon potential predict for 147Ba an octupole deformed ground state with 3 = 0.11.  相似文献   

6.
Excited states in 191Pt have been populated using the reaction 186W + 11B at 85MeV beam energy. Gamma-ray coincidences were measured using the EUROGAM-II spectrometer array. The level scheme has been extended considerably. Evidence for favoured structures of highly triaxial shape with -90° coexisting with oblate structures has been obtained by comparison with total Routhian surface and cranked shell model calculations. The presence of proton excitations in both positive- and negative-parity states has been confirmed.  相似文献   

7.
Magnetic hyperfine fields (mhf) at 111Cd and 140Ce nuclei, dilutely substituting the In and Ce sites, respectively, have been measured in the intermetallic compound CeIn3 using perturbed angular correlation technique. A pure electric quadrupole interaction with an axially symmetric electric field gradient was observed at 111In(EC)111Cd probe nuclei at room temperature while a combined magnetic dipole and electric quadrupole interaction is observed below 10K. Below the ordering temperature, only a magnetic interaction is observed at 140La()140Ce probe. The values of mhf measured experimentally as a function of temperature are discussed in terms of critical behavior.  相似文献   

8.
The 111Tc nucleus, populated in the spontaneous fission of 248Cm, was studied by means of prompt -ray spectroscopy using the EUROGAM2 array. Excited states in 111Tc were observed for the first time. Systematics of energy levels in odd-A Tc isotopes, obtained in our study of 107Tc and 109Tc provide a reliable spin and parity assignment I = 5/2+ to the head of the new band in 111Tc, interpreted as the 5/2+[422] orbital originating from the proton g9/2 shell. This level is most likely the ground state. Therefore, the (9/2+,7/2+) spin-parity assignment to the ground state of 111Tc, reported previously, is unlikely. Properties of the yrast band in 111Tc suggest prolate deformation of this band. There are hints that the deformation of 111Tc is larger than that of 109Tc, possibly due to admixtures of oblate-deformed configurations, which lower their excitation energy with increasing neutron number.  相似文献   

9.
The possibility of obtaining scintillators with a high effective atomic number of the element Z ef based on Lu3Al5O12:Ce3+ singlecrystal films (SCF) on doping with La3+ and Sc3+ ions on Y3Al5O12 substrates has been investigated. It is established that the SCF of (LuLaY)3Al5O12:Ce3+ (Z ef = 58.9 and = 6.67 g/cm2) does not rank below those of Y3Al5O12:Ce3+ (Z ef = 29 and = 4.52 g/cm2) in the conversion efficiency of radiation at the band with max = 515 nm. This allows their use as screens of xray images with a space resolution of 0.75–1.00 m. It is suggested that in the SCF of Lu3Al5O12 the isoelectronic impurities of lanthanum and scandium form radiative recombination centers of the type LaLu, ScLu, and ScAl as well as the centers Lu as a consequence of the effect of replacement of some Lu3+ ions by the La3+ ions to octanodes of the garnet lattice. The low efficiency of Ce3+ radiation in the SCF of (LuSc)3(AlSc)5O12:Ce is explained by substantial losses due to excitation of the recombination luminescence in the UV region of the centers formed by the isoelectronic impurities of scandium and to the possible existence of the channel of energy excitation dissipation related to the transitions between extrema of the allowed energy bands and activator levels.  相似文献   

10.
High-spin states of 136La have been investigated with the reaction 130Te( 11B, 5n) at a beam energy of 60 MeV. The level scheme with three collective bands has been updated with spin up to 20 . The observed h11/2 h11/2 band shows -instability with increasing spin according to the TRS calculations. The band crossing and the signature splitting and inversion have been discussed. Other two collective bands based on 12-and 16+ levels were proposed as oblate deformation with -60°. They most probably originate from four- and six-quasiparticle configurations, that is, h11/2 g7/2h11/22 and g7/2 g7/22d5/2h11/22 respectively.  相似文献   

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