Physics of Particles and Nuclei Letters最新文献

Most neutron-deficient α emitters are known to be of great relevance to the astrophysical rapid neutron capture process in superheavy nuclei. Therefore, in the present work, the decay properties of newly observed superheavy nuclei with Z = 102, i.e., (^{{249}})No isotope from the α-decay of (^{{253}})Rf is theoretically investigated using the relativistic mean field (RMF) framework and the NL3* parameter set within the preformed cluster-decay model (PCM). The α-decay chain of (^{{255}})Rf is also considered. The RMF densities are folded with the R3Y nucleon-nucleon (NN) potential to deduce the nuclear interaction potential between the decaying fragments. A complete understanding of the penetration of an α-particle across the nuclear Coulomb barrier gives outstanding credence to the assumptions of quantum mechanics. The presence of shell/sub-shell closure is indicated by the formation of peaks along the decay chain and was found to alter the conventional scaling factor observed earlier in the results of the PCM. The calculated half-lives are in close agreement with recent experimental measurements.

The SRC (Short Range Correlation) [1] experiment searches for short-period two-nucleon correlations using the detector subsystems of the BM@N (Baryonic Matter at Nuclotron) facility. Р•xperiments of this kind require an easy-to-operate, reliable system for controlling and monitoring the slowly changing parameters of the experimental hardware. These parameters are high and low supply voltages, environmental parameters, data from gas subsystems, etc. The equipment very often comes from a large number of hardware manufacturers. The Slow Control System provides solutions to the following tasks: control and monitoring parameters of detectors and other subsystems. During the operation of the experimental facility, timely detection of failures in operation and alarming of emergencies, monitoring of environmental parameters are vitally important. Archiving of facility parameters in the database for further use in the analysis of experimental data is also provided.

In this study, we investigate the Schrödinger equation equation for scalar particles on the Y^{p, q}. An equation of general Heun type is obtained for one of the coordinates and its associated Painlevé VI equation is derived. Consequently, we take some particular limits of the Y^p,q geometry, which result in a coalescence of singularities of the equation of motion. Finally, the associated isomondromic flows are examined.

We discuss formulation of QCD in Minkowski–spacetime and effect of an operator product expansion by means of normal ordering of fields in the QCD Lagrangian. The formulation of QCD in the Minkowski–spacetime allows us to solve a constraint equation and decompose the gauge field propagator in the sum of an instantaneous part, which forms a bound state, and a retarded part, which contains the relativistic corrections. In Quantum Field Theory, for a Lagrangian with unordered operator fields, one can make normal ordering by means of the operator product expansion, then the gluon condensate appear. This gives us a natural way of obtaining a dimensional parameter in QCD, which is missing in the QCD Lagrangian. We derive a Schwinger–Dyson equation for a quark, which is studied both numerically and analytically. The critical value of the strong coupling constant ({{alpha }_{s}} = {4 mathord{left/ {vphantom {4 pi }} right. kern-0em} pi }), above which a nontrivial solution appears and a spontaneous chiral symmetry breaking occurs, is found. For the sake of simplicity, the considered model describes only one flavor massless quark, but the methods can be used in more general case. The Fourier-sine transform of a function with log-power asymptotic was performed.

We rewrite the recently constructed q-hypergeometric integral Bailey pair in a general form. Then with the help of the Bailey pair and (q)-beta hypergeometric sum-integral, we construct the star-triangle relation.

Angular anisotropy of secondary neutrons is evidenced in neutron emission spectra (NES) and prompt fission neutron spectra (PFNS). In case of NES that is due to angular dependence of elastic scattering, direct excitations of discrete collective levels and pre-equilibrium/direct emission of (n, nX)¹ neutrons, while in case of PFNS it is because of these neutrons are evidenced in exclusive pre-fission neutrons in (n, xnf)¹. In ²³⁹Pu(n, xnf)^1,...x and ²³⁵U(n, xnf)^1,...x PFNS demonstrate different responses to forward and backward (n, xnf)¹ neutrons emission with respect to the incident neutron momentum. Average energy of (n, nf)¹ neutrons depends on the emission angle θ, i.e., fission cross section, prompt neutron number and total kinetic energy depend on θ as well. Exclusive neutron spectra (n, xnf)^1,...x at θ ~ 90° are consistent with ²³⁵U(n, F)(²³⁵U(n, xn)) and ²³⁹Pu(n, F)(²³⁹Pu(n, xn)) reaction cross sections within E_n ~ 0.01–20 MeV energy range. Exclusive neutron spectra of (n, xnf)^1,..x, (n, nγ) and (n, xn)^1,...x are calculated within Hauser–Feshbach formalism alongside with (n, F) and (n, хn) reaction cross sections, angular dependence of first neutron (n, nX)¹ emission (omega (theta )) being included. Approximation obtained for (omega (theta )) fits the measured NES at 14 MeV. The correlation of angular dependence of (n, xnf)¹ neutron emission with emissive fission (n, xnf) contribution to the observed fission cross section and angular anisotropy of NES. The ratios of mean PFNS energies (leftlangle E rightrangle ) for forward and backward emission of ²³⁵U(n, xnf) and ²³⁹Pu(n, xnf) pre-fission neutrons are consistent with measured data.

This paper presents the results of studying the yield averaged over the bremsstrahlung flux of the promising medical radioisotope ¹⁷⁷Lu in the (γ, p) reaction from hafnium targets enriched in ¹⁷⁸Hf (92%) after irradiation with electron bremsstrahlung at a cutoff energy of 55 MeV. An assessment is made of the conditions under which the ¹⁷⁷Lu can be produced in quantities necessary for nuclear medicine. The amount of ^177mLu and other accompanying isotopes of lutetium that form simultaneously with ¹⁷⁷Lu in the proposed production method is estimated.

The prototype of polarized deuteron source was made for the Van de Graaff accelerator of the Czech Technical University in Prague with aim to create full scale setup for producing polarized neutron beam for experiments on measurement (Delta {{sigma }_{{text{L}}}}) and (Delta {{sigma }_{{text{T}}}}), longitudinal and transversal spin asymmetries in transmission polarized neutron beam through frozen polarized deuteron target. It is based on Kaminsky’s experiment on channeling deuterons through a magnetized Ni single crystal foil of 1–2 μm. It is proposed to use the reaction T({{(d,n)}^{4}})He with polarized deuterons of an energy 150–200 keV. For a nonchanneled beam (the goniometer in a random position), the tensor polarization measurements were carried out with a TiT target. Our result is ({{P}_{{zz}}} = - 0.10 pm 0.02). This result indicates that deuterium atoms that have passed outside the channels also become polarized due to the capture of polarized electrons from the nickel crystal.

Iterative solution of the evolution equation of parton distribution functions in QED is discussed. The results for the functions of positron-in-electron type are given in the next-to-leading logarithmic approximation.

In this paper we present the results of a study of a high-voltage 32-channel DAC AD5535 for powering silicon photomultipliers. Built-in high-voltage buffer amplifiers allow output voltage regulation in the range of up to 200 V which provides application for a broad SiPM types including their serial connection. The significant output current of 500 μA/ch allows biasing the SiPM arrays and assemblies. The documentation indicates a significant temperature dependence of (sim ~200~) ppm/C which limits the use of DAC for SiPM powering. This work demonstrates the excellent temperature stability of the chip. Still since the manufacturer does not guarantee this an express method of channel-by-channel measurement of temperature dependence has been developed for a mass use of the AD5535 DAC