Isomeric States Of Nuclei Research Articles

Isomeric states in neutron-rich nuclei near N=40

Neutron-rich nuclei in the vicinity of the $N=40$ island of inversion are characterized by shell evolution and exhibit deformed ground states. In several nuclei isomeric states have been observed and attributed to excitations to the intruder neutron $1g_{9/2}$ orbital. In the present study we searched for isomeric states in nuclei around $N=40$, $Z=22$ produced by projectile fragmentation at RIBF. Delayed $\gamma$ rays were detected by the EURICA germanium detector array. High statistics data allowed for an updated decay scheme of $^{60}$V. The lifetime of an isomeric state in $^{64}$V was measured for the first time in the present experiment. A previously unobserved isomeric state was discovered in $^{58}$Sc. The measured lifetime suggests a parity changing transition, originating from an odd number of neutrons in the $1g_{9/2}$ orbital. The nature of the isomeric state in $^{58}$Sc is thus different from isomers in the less exotic V and Sc nuclei.

Favored configurations for four-quasiparticleKisomerism in the heaviest nuclei

Configuration-constrained potential-energy-surface calculations are performed including ${\ensuremath{\beta}}_{6}$ deformation to investigate high-$K$ isomeric states in nuclei around ${}^{254}$No and ${}^{270}$Ds, the heaviest nuclei where there have been some observations of two-quasiparticle isomers, while data for four-quasiparticle isomers are scarce. We predict the prevalent occurrence of four-quasiparticle isomeric states in these nuclei, together with their favored configurations. The most notable examples, among others, are ${K}^{\ensuremath{\pi}}={20}^{+}$ states in ${}^{266,268}$Ds and ${}^{268,270}$Cn having very high $K$ value, relatively low excitation energy, and well-deformed axially symmetric shape. The predicted isomeric states, with hindered spontaneous fission and $\ensuremath{\alpha}$ decay, could play a significant role in the future study of superheavy nuclei.

Integral cross section of the isomeric state <sup>113</sup>In, <sup>115</sup>In, <sup>111</sup>Cd, <sup>117</sup>Sn, <sup>187</sup>Sr in (γ,γ′) reaction

The integral cross sections of the isomeric states of nuclei 113 In, 115 In, 111 Cd, 117 Sn, 87 Sr in (γ,γ¢) reactions, under the bremsstrahlung influence from the electrostatic accelerator of electrons with the voltage applied to a conductor being up to 3.0 MV are present.

On previous and present investigations of resonance gamma-ray interaction with nuclei at the Institute of Theoretical and Experimental Physics (ITEP, Moscow)

A brief survey of theoretical and experimental work that is devoted to studying the resonance absorption and scattering of gamma rays by nuclei and which was initiated at the Institute of Theoretical and Experimental Physics (ITEP, Moscow) in the 1950s and has been continued to date is given. Investigations of various versions of interaction in beta decay, magnetic-field-perturbed angular distributions of resonantly scattered gamma rays, the problem of the Mossbauer gamma resonance of long-lived isomeric states of nuclei, and the resonance scattering of annihilation photons by nuclei are described.

Searches for effects of fundamental-symmetry violation in isomeric nuclear states

The results of broad searches for schemes that are convenient for observing effects of time-inversion-invariance violation (T violation) simultaneously with parity violation (PT violation) in electromagnetic transitions in nuclei are presented. The main problems in observing such effects are discussed. A scheme that seems one of the most promising for this and which relies on measuring the linear polarization of gamma radiation accompanying the deexcitation of isomeric states of nuclei that were oriented by a magnetic field at ultralow temperatures is highlighted.

Mixed Symmetry Isomeric States in Nuclei**The project supported by Major State Basic Research Development Program under Contract No. G200077400, National Natural Science Foundation of China, Pok Yin Tung Education Foundation and Excellent Young University Teacher's Fund of Education Ministry of China

Mixed symmetry states are studied in the framework of the neutron-proton interacting boson model. It is found that some of the mixed symmetry states with moderate high spins change very fast with respect to the Majorana interaction. Under certain conditions, they become the yrast state or yrare state. These states are difficult to decay and become very stable. This study suggests that a possible new mode of isomers may exist due to the special nature in their proton and neutron degrees of freedom.

Calculation of the effects of neutron activation of nuclei for cases of superposition of the signal in gamma activation analysis

A proposed method is presented for calculating the contribution of neutron activation to the analytical signal for the pair of reactions (gamma, gamma'), which is of special interest for gamma activation analysis. The prospects for the exploitation of the reactions (gamma, gamma') in gamma activation analysis is demonstrated. The proposed method for calculating the contributions of neutron activation of isomeric states of nuclei for the model case of activation of indium samples studied here in a real bremmstrahlung beam from an electron accelerator gives reasonable agreement for both the relative contributions Y /SUP O/ /SUB n/ , /SUB n/ '/Y and Y /SUP p/ /SUB n/ , n'/Y and the energy dependence of these contributions. The computational method described can be used both in formulating experiments for determining the yields of photoactivation of nuclei by electron accelerators and for optimizing the conditions for determining elements in gamma activation analysis.