Physics of Particles and Nuclei Letters最新文献

The MPD detector is one of two at NICA collider. For MPD detector control system the TANGO software was proposed. Time projection chamber (TPC) is the tracker of the MPD. The TPC LV and HV systems are based on CAEN equipment and OPC UA server protocol. The status of interface design for CAEN equipment based on OPC UA, TANGO server and GRAFANA is presented. GRAFANA will be used to present graphs of the variation in the parameters of HV and LV during the monitoring.

JINR in collaboration with the St. Petersburg-based Efremov Institute of Electrophysical Apparatus (NIIEFA) is developing a superconducting isochronous cyclotron MSC230, which is intended to conduct research in radiobiology and to develop proton flash radiotherapy techniques. In relation to this, formation of a high-intensity proton beam with the energy selectable in a range of 120–230 MeV, a dose rate of 50–100 Gy/s, and homogeneous in cross section with a diameter of 13–15 cm at the new accelerator is explored. Results of modeling by the Monte Carlo method and measurements of the depth-dose distributions of a proton beam, the energy spectrum of which is modified to obtain an extended homogeneous plateau at the end of the range (spread-out Bragg peak), are presented. This is achieved by using so-called ridge filters. A method for design and manufacturing ridge filters using a 3D printer that can change the length of the plateau in a fairly wide range of values by rotating it relative to the beam axis is presented. The results of the study lend a hope that two sets, each consisting of 5–6 such filters, will be able to span the entire required range of the Bragg peak plateau, and for all values of the selected energy.

This study is a search for means of sensitization of malignant tumors to proton radiation among DNA damage repair inhibitors. It has been found that in the presence of 1-β-D-arabinofuranosylcytosine (AraC), five weekly proton irradiations at a total focal dose of 50 Gy lead to a more pronounced inhibition of B16 murine melanoma growth than the same irradiation without AraC (p < 0.05 ). This effect, associated with a decrease in the proliferative activity of cells in the general population and a decrease in the number of cancer stem cells specifically in the AraC+Protons group, is promising for further improvement of proton radiotherapy.

The mechanism for the appearance of large values of the relative orbital momenta L of the fragments of spontaneous nuclear fission is shown to be associated with quantum transverse wriggling vibrations of the fissile nucleus at its rupture point. This mechanism assumes that the fissile nucleus remains cold up to its rupture into fission fragments. Based on the considered mechanism, an analytical formula was derived for the first time to estimate the average value of the orbital momentum and the angular distribution of fission fragments. The results obtained are an important contribution to the understanding of nuclear fission, and have important significance in problems of heat release in nuclear reactors arising from the propagation of instantaneous gamma rays emitted by fission fragments.

This study explores the features of a two-dimensional Kemmer oscillator within the context of relativistic quantum mechanics. By rigorously deriving eigenstates and conducting thermal analysis using the Euler–Maclaurin method, we aim to unveil the subtleties of its dynamics. Our inquiry endeavors to shed light on the thermal characteristics of the system, thus enriching our comprehension of relativistic quantum phenomena.

For the flat FLRW model of Universe evolution in RTG a new model of dark energy is proposed. It is a global scalar field (Phi ) with the (frac{{{{mu }^{2}}{{Phi }^{2}}}}{2}) potential. It ensures cosmological acceleration at the present time and a bounce at the latе times. At the contraction stage Kazner-like growing anisotropy of Riemannian metrics will break a mass of the graviton bounce mechanism near the Big Bang in FLRW case. It. In order to save the cyclic model one probably has to add some exotic fields, like galileons etc. There is also noncyclic option, when small enough graviton mass terms are significant only at the end of expansion. During next contraction epoch after bounce, an anisotropy grows and the matter density finally reaches the Planck one.

We have shown the feasibility of detecting gamma quanta in a neutron experiment in the mode of resonantly enhanced standing waves (RESW) from a 1 nm thick gadolinium film placed in a resonator structure consisting of a 50 nm niobium layer on a sapphire substrate and coated with a 10 nm tantalum-copper film alloy. The mass of gadolinium used in the experiment was 2 μg, which is 25 times less than that in the experiment by H. Zhang et al. (H. Zhang et al., Phys. Rev. Lett. 72, 3044 (1994)). Quantitative calculations show that the experimental conditions make it possible to detect a gamma signal at waveguide resonance from a gadolinium sample weighing 40 nanograms. Thus, RESW gamma spectrometry is a powerful method for characterizing heterostructures with ultrathin gadolinium layers. In particular, it can be used to study the kinetics of interaction of hydrogen with nanometer films in which a thin layer of gadolinium is used as a label layer.

Detector system has been designed for recording ultraweak optical emission from biological samples. Saccharomyces boulardii samples was used to confirm the operability. Principles of designing the detector and registration systems of ultraweak optical emission described. The measurements confirmed the correct operation of designed detector system and shows, that the reason of emission is a samples thermal induction.

The finite-element analysis of three-dimensional magnetostatic problems in terms of magnetic vector potential has proven to be one of the most efficient tools capable of providing the excellent quality results but becoming computationally expensive when employed to modeling of large-scale magnetization problems in the presence of applied currents and nonlinear materials due to substantial number of the model degrees of freedom. In order to achieve a similar quality of calculation at lower computational cost, we propose to use for modeling such problems the combination of magnetic vector and total scalar potentials as an alternative to magnetic vector potential formulation. The potentials are applied to conducting and nonconducting parts of the problem domain, respectively and coupled together across their common interfacing boundary. For nonconducting regions, the thin cuts are constructed to ensure their simply connectedness and therefore the consistency of the mixed formulation. The implementation in the finite-element method of both formulations is discussed in detail with difference between the two emphasized. The numerical performance of finite-element modeling in terms of combined potentials is assessed against the magnetic vector potential formulation for two magnetization models, the Helmholtz coil, and the dipole magnet. We show that mixed formulation can provide a substantial reduction in the computational cost as compared to its vector counterpart for a similar accuracy of both methods.