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卷 88, 编号 3 (2025)
ЯДРА. Эксперимент
Photoneutron Reaction Cross Sections for 115In
摘要
New data for cross sections of partial reactions (g, 1n) and (g, 2n) were obtained using both published data for neutron yield cross-section σ(g, xn) = σ(g, 1n) + 2σ(g, 2n) and total photoneutron reaction cross-section σ(g, sn) = σ(g, 1n) + σ(g, 2n) determined in experiment on the bremsstrahlung beam. The investigation of reliability of those cross sections was carried out using the experimental–theoretical method for partial reaction cross sections evaluation basing on physical criteria. It was found that new evaluated cross sections of the reactions 115In(γ, 1n)114In and 115In(γ, 2n)113In not meeting physical criteria of reliability differ in a certain way from experimental ones. The comparison of new evaluated data with the results of analogous evaluation basing on the results for partial reaction cross sections for 115In obtained in experiment on the beam of quasimonoenergetic annihilation photons shows that both evaluations are close.
Physics of Atomic Nuclei. 2025;88(3):245-255
245-255
Angular distribution of g-quanta in reactions with light particles on the 12C nucleus, determined with the help of particle–g-correlations
摘要
The angular correlation function of a finite particle y and a g-quantum is used to analyze the angular distribution of g-radiation, which removes the excitation of the nucleus, formed in a nuclear reaction. The experimental and calculated angular distributions of g-radiation during the deexcitation of the 12C(2+) nucleus in inelastic scattering of deuterons and neutrons are compared. In the inelastic scattering of deuterons with an energy of 15.3 MeV, the analysis was performed using the experimental and calculated values of the spin tensors of the 12C(2+) density matrix, determined by us earlier. In the inelastic scattering of neutrons with an energy of 14.1 MeV, the experimental angular distribution of g-quanta (TANGRA collaboration) is compared with that calculated on the basis of spin tensors defined in the coupled-channel method. The normalized angular distributions of g-quanta in the scattering of both deuterons and neutrons are consistent with the experimental ones. It is shown that the anisotropy of g-radiation in inelastic neutron scattering is 1.5 times higher than the anisotropy in inelastic deuteron scattering.
Physics of Atomic Nuclei. 2025;88(3):256-263
256-263
ЭЛЕМЕНТАРНЫЕ ЧАСТИЦЫ И ПОЛЯ. Эксперимент
SND@LHC IN 2025 AND BEYOND
摘要
SND@LHC experiment investigates processes involving neutrinos generated at the Large Hadron Collider in the region of pseudorapidities 7.2 < η < 8.6. The detector includes a target of 830 kg consisting of tungsten plates alternating with emulsion and electronic detectors, behind which a hadron calorimeter and a muon detection system are located. The detector’s design provides a unique opportunity to study the generation of the charmed particles in the pseudorapidity region inaccessible to other LHC experiments. The paper presents the current state of the experiment and the prospects for the coming years.
Physics of Atomic Nuclei. 2025;88(3):264-273
264-273
MEASUREMENT OF THE E+E– → P0Γ CROSS SECTION NEAR THE Φ(1020) RESONANCE WITH THE SND DETECTOR
摘要
The e+e− →p0γ cross section has been measured in the center-of-mass energy range from 1000 to 1060 MeV with the SND detector at the VEPP-2000 e+e− collider. At the maximum of the φ(1020) resonance the systematic uncertainty of the cross section measurement is 1.3%, and the statistical uncertainty is 2.2%. To date this is the most accurate measurement of the e+e− →p0γ cross section. As a result of data approximation with the vector dominance model the decay probability B(φ→p0γ )= (1.452 ± 0.024 ± 0.067)×10−3 has been measured.
Physics of Atomic Nuclei. 2025;88(3):274-285
274-285
Determination of neutron yield from “thick” Be target irradiated with 21.5 MeV protons using a proton beam monitoring system
摘要
The results of determining the neutron yield of the NS-21M facility, based on the I-2 linear proton accelerator and 3.8 mm thick Be target under bombardment by 21.5 MeV protons, are presented. This value was obtained by calculating the integral neutron flux passing through the front hemisphere at a specified distance from the center of the Be target relative to the average proton flux transmitted through a collimator of defined diameter. The experimental value of this quantity is = (1.35 ± 0.09) × 10–², while the calculated value = 1.18 × 10–² was derived by simulating the full mathematical model of the NS-21M stand using the PHITS-3.31 transport code. For 21.2 MeV protons, reaction cross-sections of natCu(p, x)61Cu, 62Cu, and 64Cu were determined using the monitor reactions natCu(p, x)62Zn and natCu(p, x)63Zn. Simulated excitation functions for these reactions (TENDL-2023, JENDL-5, PADF-2, and PHITS-3.31 with the INCL model) were plotted over the 0.01–3 GeV range alongside experimental data from EXFOR.
Physics of Atomic Nuclei. 2025;88(3):286-302
286-302