Mass number and excitation energy dependence of the Θeff/Θrig\Theta_{eff}/\Theta_{rig} parameter of the spin cut-off factor in the formation of an isomeric pair

The $\Theta_{eff}/\Theta_{rig}$ parameter of the spin distribution of the level density was determined for 61 nuclei covering the mass range of 44 to 200. The experimental isomeric cross-section ratios for 25 isomeric pairs were compared with the model calculation to find the best fit to the experimental data. The model calculations were carried out with the TALYS code using the BSFG model for the level density. The reduced $\chi ^2$ values were calculated to describe the deviation of the experimental data from the model calculation. An $\eta_d$ was introduced calculating the $\Theta_{eff}/\Theta_{rig}$ value from the low energy discrete levels of the nucleus. The $\eta /\eta_d$ values seem to be independent of the mass number, their average value near to one. The $\eta /\eta_d$ values also seem to be independent of the average excitation energy in the continuum, indicating that $\eta$ is independent of the excitation energy. The mass number and (N-Z) dependence of the $\eta$ values were studied. The $\eta$ values for the nuclei with odd mass number show an exponential decrease as a function of A or (N-Z). The $\eta$ values for the odd-odd type of nuclei appear to be constant, near one, up to the mass number 110 or (N-Z) of 13. Above these values, the $\eta$ values show exponential decrease. The $\eta$ values for even-even type nuclei decrease exponentially up to A equal to 142 or (N-Z) equal to 20. The values are lower than those for the nearby odd-odd type nuclei. The $\eta$ values increase for nuclei with A between 142 and 156 and (N-Z) between 20 and 28, and they finally reach the value of odd-odd type systematics.Comment: 67+3 pages, 52+2 figures. Calculations with EMPIRE have been added to Section IV.

Covariance and Fisher information in quantum mechanics

Variance and Fisher information are ingredients of the Cramer-Rao inequality. We regard Fisher information as a Riemannian metric on a quantum statistical manifold and choose monotonicity under coarse graining as the fundamental property of variance and Fisher information. In this approach we show that there is a kind of dual one-to-one correspondence between the candidates of the two concepts. We emphasis that Fisher informations are obtained from relative entropies as contrast functions on the state space and argue that the scalar curvature might be interpreted as an uncertainty density on a statistical manifold.Comment: LATE

Excitation functions of 3He-particle-induced nuclear reactions on 103Rh: Experimental and theoretical investigations

Excitation functions for the 3He-induced reactions on 103Rh as alternative pathway for the production of the medically used 103Pd were studied by the stacked foil technique. Excitation functions of the 103Rh(3α, x) 103Pd, 103,104,104m,105Ag and 100,101,101m,102,102mRh reactions were determined up to 27 MeV by detecting only the characteristic γ-rays obtained from the decay of residual nuclei. The experimental results were compared with the theoretical ones obtained from the EMPIRE-3.2 code and ‎the TENDL nuclear data library. From the measured cross-section data integral production yields were calculated

Particulate Fillers in Thermoplastics

The characteristics of particulate filled thermoplastics are determined by four factors: component properties, composition, structure and interfacial interactions. The most important filler characteristics are particle size, size distribution, specific surface area and particle shape, while the main matrix property is stiffness. Segregation, aggregation and the orientation of anisotropic particles determine structure. Interfacial interactions lead to the formation of a stiff interphase considerably influencing properties. Interactions are changed by surface modification, which must be always system specific and selected according to its goal. Under the effect of external load inhomogeneous stress distribution develops around heterogeneities, which initiate local micromechanical deformation processes determining the macroscopic properties of the composites

Influence of reaction channel on the isomeric cross-section ratio

The influence of reaction channel on the isomeric cross-section ratio was investigated by analysing the experimental data on the reactions Cr-52(p, n)Mn-52m,Mn-g, Cr-52(He-3, t)Mn-52m.g, Fe-54(d, alpha)Mn-52m.g, Fe-54(n, t)Mn-52m.g and Fe-54(He-3, alpha p)Mn-52m.g over the incident particle energy range extending up to 35MeV. The influence is most pronounced when the channels differ widely, for example (p,n) and (He-3, t) processes, i.e. when the reaction mechanisms are different. The nuclear model calculational code EMPIRE-II described the isomeric cross-section ratio rather well in the case of a simple nucleon emission reaction, but not when complex reaction channels were involved

Formation of the isomeric pairs 139m,gNd and 141m,gNd in proton and 3He-particle induced nuclear reactions

Cross sections were measured by the activation technique for the nuclear reactions Pr-141(p,n)Nd-141(m),Pr-141(p,3n)Nd-139(m),Ce-nat(He-3,xn)Nd-141(m), and Ce-nat(He-3,xn)Nd-139(m) up to proton energies of 44 MeV and He-3-particle energies of 35 MeV. Using the present data and some of our earlier experimental results the isomeric cross-section ratios for the nuclide pairs Nd-139(m,g) and Nd-141(m,g) were calculated. The experimental data were compared with the results of nuclear model calculations using the code STAPRE, which combines the statistical and precompound formalisms. In general the experimentally determined excitation functions as well as the isomeric cross-section ratios could be described by the theory within the limits of experimental uncertainties, but using relatively low values of eta [i.e., the ratio of the effective moment of inertia to the rigid-body moment of inertia (Theta(eff)/Theta(rig))]. The mass dependence of eta could be confirmed

Cross sections for the formation of 69Znm,g and 71Znm,g in neutron induced reactions near their thresholds: Effect of reaction channel on the isomeric cross-section ratio

Excitation functions were measured for the reactions Ge-72(n,alpha)Zn-69(m,g), Ga-69(n,p)Zn-69(m,g), Zn-70(n,2n)Zn-69(m,g), Ge-74(n,alpha)Zn-71(m,g), and Ga-71(n,p)Zn-71(m,g) over the neutron energy range of 6.3-12.4 MeV. Quasimonoenergetic neutrons in this energy range were produced via the H-2(d,n)He-3 reaction using a deuterium gas target at the Julich variable energy compact cyclotron. Use was made of the activation technique in combination with high-resolution HPGe-detector gamma-ray spectroscopy. In a few cases low-level beta(-)counting was also applied. In order to decrease the interfering activities in those cases, either radiochemical separations were performed or isotopically enriched targets were used. For most of the reactions, the present measurements provide the first consistent sets of data near their thresholds. From the available experimental data, isomeric cross-section ratios were determined for the isomeric pair Zn-69(m,g) in (n,alpha), (n,p), and (n,2n) reactions, and for the pair Zn-71(m,g) in (n,alpha) and (n,p) reactions. Nuclear model calculations using the code STAPRE, which employs the Hauser-Feshbach (statistical model) and exciton model (precompound effects) formalisms, were undertaken to describe the formation of both isomeric and ground states of the products. The calculational results on the total (n,alpha), (n,p), and (n,2n) cross sections agree fairly well with the experimental data. The experimental isomeric cross-section ratios, however, are reproduced only approximately by the calculation. For both the isomeric pairs investigated, the isomeric cross-section ratio in the (n,p) reaction is higher than in other reactions

Cross sections and isomeric cross-section ratios in the interactions of fast neutrons with isotopes of mercury

Excitation functions were measured for the reactions Hg-196(n, 2n)Hg-195(m,g),Hg-198(n, 2n)Hg-197(m,g),Hg-204(n, 2n)Hg-203,Hg-198(n,p)Au-198(g), and Hg-199(n,p)Au-199 over the neutron energy range of 7.6-12.5 MeV. Quasimonoenergetic neutrons were produced via the H-2(d,n)He-3 reaction using a deuterium gas target at the Julich variable energy compact cyclotron CV 28. Use was made of the activation technique in combination with high-resolution, high-purity Ge detector gamma-ray spectroscopy. All the data were measured for the first time over the investigated energy range. The transition from the present low-energy data to the literature data around 14 MeV is generally good. Nuclear model calculations using the codes STAPRE and EMPIRE-2.19, which employ the statistical and precompound model formalisms, were undertaken to describe the formation of both the isomeric and ground states of the products. The total reaction cross section of a particular channel is reproduced fairly well by the model calculations, with STAPRE giving slightly better results. Regarding the isomeric cross sections, the agreement between the experiment and theory is only in approximate terms. A description of the isomeric cross-section ratio by the model was possible only with a very low value of eta, i.e., the Theta(eff)/Theta(rig) ratio

Cross sections for the formation of 195Hgm,g, 197Hgm,g, and 196Aum,g in alpha and 3He-particle induced reactions on Pt: Effect of level density parameters on the calculated isomeric cross-section ratio

Excitation functions were measured for the reactions Pt-nat(He-3,xn)Hg-195(m,g),Pt-nat(He-3,xn)Hg-197(m,g),Pt-nat(He-3,x)Au-196(m,g), and Pt-nat(alpha,xn)Hg-197(m,g) over the energy range of 18-35 MeV for He-3 particles and 17-26 MeV for alpha particles. The reactions Au-197(p,n)Hg-197(m,g) were also investigated over the proton energy range of 6-20 MeV. The three projectiles were produced at the Julich variable-energy compact cyclotron (CV 28). Use was made of the activation technique in combination with conventional high-resolution as well as low-energy HPGe-detector gamma-ray spectroscopy. For most of the reactions, the present measurements provide the first consistent sets of data. From the available experimental data, isomeric cross-section ratios were determined for the above-mentioned reactions. Nuclear model calculations using the code STAPRE, which employs the Hauser-Feshbach (statistical model) and exciton model (precompound effects) formalisms, were undertaken to describe the formation of both the isomeric and the ground states of the products. The calculations were compared with the results of the EMPIRE-II code. The excitation functions of the (He-3,xn) and (alpha,xn) processes are described well by the theory. In the case of (He-3,pxn) reactions, however, considerable deviations were observed between the experiment and the theory, presumably due to strong contributions from direct interactions. A description of the isomeric cross-section ratio by the model was possible only with a very low value of eta, i.e., the Theta(eff)/Theta(rig) ratio. A mass dependence of eta is proposed