Conveners
Section 2. Experimental and theoretical studies of nuclear reactions
- Nikita Prokofyev (Saint Petersburg State University, Russia)
Section 2. Experimental and theoretical studies of nuclear reactions
- Nikolai Maltcev (St. Petersburg State University (RU))
Section 2. Experimental and theoretical studies of nuclear reactions
- Vladislav Sandul (St Petersburg State University (RU))
Section 2. Experimental and theoretical studies of nuclear reactions
- Alexaner Zharov (Saint Petersburg State University, Russia)
- Agniya Zvyagina (Saint Petersburg State University)
Section 2. Experimental and theoretical studies of nuclear reactions
- Vitalii Petrov (St Petersburg State University (RU))
Numerical solution of the time-dependent Schrödinger equation [1-3] is used for studying the dynamics of breakup reaction and nucleon transfer at energies above the Coulomb barrier. The spin-orbit interaction is taken into account [2]. The evolution of the wave functions for an outer weakly bound two neutrons of $^{11}$Li nucleus and one neutron of $^{11}$Be in collisions with $^{28}$Si and...
Total reaction cross section (σR) values for interaction 10,11,12Be cocktail beam particles with 28Si, 59Co, 181Ta target nuclei in the energy range
12–48 A·MeV are presented. Experimental method of direct measuring of σR is based on detection of prompt n, γ radiation by 12 CsI(Tl) detectors γ-spectrometer [1] was used. A comparison of the two methods for calculating the total cross sections...
An analysis of cross sections of elastic scattering of $^{17}$F on
$^{12}$C, $^{14}$N, $^{58}$Ni, and $^{208}$Pb nuclei at energy 170
MeV and on $^{208}$Pb at various energies is carried out by using
the microscopic optical potentials (OPs). The proton and neutron
density distributions of the exotic nucleus $^{17}$F are computed
in the framework of microscopic models. The real part of the...
Potential Energy calculations are the basis for static and dynamic studies of the nuclear fission process. Calculation of surface, nuclear, Coulomb, rotational functionals, curvature, congruence, and Wigner energy functionals was recently presented for a wide variety of nuclear shape parameterizations [1].
Current approaches typically aim to achieve a theoretical description of the potential...
At present, at low astrophysical energies there is experimental information on the cross sections of the reactions $^9$Ве$(р,d_0)$ and $^9$Ве$(р,α_0)$ obtained by different authors [1-14]. Nevertheless, as shown in the review [15], the extrapolation of the S-factors of these reactions to zero energy has a large uncertainty (the difference is up to 10 times). This is partly due to the many...
The 13C(α,n)16O reaction cross section plays an important role as the background source in the geoneutrinos measurements and as the source of neutrons for the s-process in nuclear nucleosynthesis. The cross section for its reverse reaction is important for the number of practical applications, including the design of the nuclear power plants, the assessment of helium accumulation in structural...
In experimental papers [1, 2] the yields, angular and energy distributions of the pairs of light third and fourth particles, such as $\alpha$-particles pair $(\alpha_1,\alpha_2)$, were obtained for the spontaneous quaternary fission of the nuclei $^{252}$Cf, $^{248}$Cm and for the induced by thermal neutrons quaternary fission of compound nuclei $^{234}$U, $^{236}$U. Using the theoretical...
Nuclear data obtained in the neutron induced fission of 232Thorium are of a great importance for advanced fast reactors based on Th fuel cycle. Fission cross sections, mass and charge distributions, prompt emission in fission including neutron multiplicities, yields of some isotopes of interest, and associated uncertainties were obtained. This paper presents the theoretical predictions and the...
In the framework of the “Energy and Transmutation of RAW” collaboration [1], the experiments were carried out at the accelerators: Nuclotron, Phasotron and LINAC of JINR and have studied deeply of nuclear inelastic processes using gamma spectroscopy techniques and HPGe detector.
The neutron fields on the proton beam were created using the lead and uranium targets. The field of the...
The experiments in the framework of the project “Energy and Transmutation” were carried out with the use of the Phasotron and LINAC-200 accelerators at JINR. The samples were placed in the neutron fields produced by the interaction of the proton beam with the lead target or in the bremsstrahlung radiation fields, which were produced in the lead converters irradiated with the electron beams....
The hidden-variables (HV) theory was once put forward by opponents of the probabilistic interpretation of the wave function (EPR paradox). It was assumed that the state of the system could be predicted with a less uncertainty than this is admitted by the Heisenberg uncertainty principle, if one knew additional, that is HV. This theory is rejected by the community. However, examples can be...
In previous works [1–3], we measured spectra of delayed neutrons (DNs) from photofission of 238U and looked for short-lived components in these DNs (with half-life T1/2 down to 1 ms) in time intervals between pulses of the linear electron accelerator at the energy of incident on metal U-target electrons Ee = 10 MeV. Fast neutrons were registered by scintillation stilbene (thickness 50 mm,...
The study of the production of actinides in the neutron field of the “Quinta” uranium target was carried out within the framework of the “Energy – Transmutation” project at the accelerators of JINR: Nuclotron and Phasotron.
The purpose of this work is to compare the yields of capture and fission reactions at various energies of the charged particles in a range from 1 to 20 GeV,...
In the framework of the “Energy + Transmutation” [1] project, the experiments have been carried out at the LINAC-200 accelerator of JINR. The 209Bi samples were irradiated in the field of bremsstrahlung radiation by the 180 MeV electrons. The bismuth was used as a converter to obtain the bremsstrahlung radiation, Figure 1.
The gamma spectra of the 209Bi activated samples were studied...
Heavy-ion-induced projectile fragmentation reactions at Fermi energies are of general interest as a means to investigate the properties of nuclei far from the valley of stability and for various applications. It is thus of importance to understand in detail the production mechanism. Here we treat such reactions in a microscopic approach, which consists of three steps: initialization of ground...
A Systematic Study of Excitation Functions of Various Evaporation Residues in Heavy Ion Reactions at Moderate Excitation Energy: Incomplete Fusion Vs Complete Fusion
Avinash Agarwal1*, Anuj Kumar Jashwal1, I. A. Rizvi2, R. Kumar3 and A. K. Chaubey4
1 Department of Physics, Bareilly College, Bareilly, MJPR University, Bareilly – 243001 INDIA
2 Department of Physics, Aligarh Muslim...
The alpha (α) emission is one of the prominent ground state decay mechanism, which is used as investigating tool to understand the relative stability of a nuclear isotopes. In last few decades, many experimental and theoretical attempts were made to understand the cluster-core interplay of radioactive nuclei. The preformed cluster model (PCM) [1,2] have successfully explored α-particle and...
Nuclear reactions induced by fast neutrons starting from 0.5 MeV up to 25 MeV followed by alpha particles emission were investigated. Cross sections, angular correlations and related asymmetry effects were evaluated with Talys [1] and own computer codes. Contribution to the cross section of nuclear reaction mechanisms like direct, compound and pre-equilibrium together with discrete and...
The neutron beam of the RADEX channel of the INR RAS is used by us to study few-nucleon reactions caused by neutrons with an energy of $10-100$ MeV. The registration in the coincidence of neutrons and charged particles, their identification and energy determination are necessary for study such reactions. For the preliminary test measurements, the reaction $n + ^{6}\text{Li} \rightarrow \alpha...
The total photoneutron yield reaction cross sections (,xn) = (,1n) + 2(,2n) + 3 (,3n)+… for 208Pb were obtained in experiments carried out using bremsstrahlung, quasimonoenergetic annihilation photons (Livermore (USA) [1] and Saclay (France) [2], and tagged photons [3]. Available data were evaluated using the method of reduction – the special treatment for converting different...
Since for spontaneous and low-energy induced fission, compound fissile nuclei and primary fission fragments in the vicinity of the scission point are in cold nonequilibrium states [1], when constructing the spin distributions of these fragments, it is necessary to take into account [2,3] only zero transverse bending- and wriggling-vibrations of the indicated fissile nuclei. Expressing the...
We analised the fission cross-section of Pb-204, Pb-206, Pb-207 and Pb-208 nuclei at neutron energies varied from 30 MeV up to 180 MeV. Experimental data were obtained from [1]. The main parameters influence the calculated fission cross-sections are the height of the fission barrier and the level density at the top of the barrier. The height of the barriers are determined by the shell...
The discovery of the Super Heavy Elements (SHE) with atomic number Z=113-118 as well as new neutron excess isotopes of the elements with Z=104-112 was one of the outstanding scientific results of the last decades. These high priority experiments were carried out on the cyclotron U400 of the FLNR (JINR, Dubna, Russia). The synthesis of the new super heavy elements stimulated works on the...
After Leemann et al. [1] experimentally demonstrated that the thermonuclear reaction cross section of $^{3}He(d,p)^{4}He$ could be increased by a factor of 1.5 by using polarized reactants, theorists [2] showed that the same effect could be achieved with other reactions, in particular, in $^{2}H(d,p)^{3}H$ and $^{2}H(d,n)^{3}He$. The usage of polarized particles could lead to improvements of...
Cross sections from the complete fusion reaction of 40Ar + 144Sm were measured by the catcher foil method [1] (on the U400M cyclotron at the Flerov Laboratory of Nuclear Reactions). The catchers were made out of five aluminum foils (0.8 µm thick) stacked downstream from the target. The experiment was carried out in repetitive short cycles (10 s). The foils were periodically moved from the beam...
The complete fusion - excitation functions of xn-evaporation channels of the reactions 144Sm(40Ar, xn){184-x}Hg, 148Sm(36Ar, xn){184-x}Hg, 144Nd(40Ca, xn)^{184-x}Hg, 142Nd(48Ca, xn)^{190-x}Hg, and 166Er(40Ar, xn)^{206-x}Rn have been measured by using the catcher foil method [1]. A modified version this technique was applied allowing to measure decay properties of α-radioactive...
This research focused on photoneutron production determination using two different photoneutron converters BeO, D2O. Experiment was carried out on a linear electron accelerator [1] in A. Alikhanyan National Laboratory in Yerevan, Armenia. A set of targets was irradiated by 70MeV electron beam. Reaction rates were determined as a result of investigations. Besides experimental results, a number...
The study of the cross-sections and yields for the population of high-spin isomeric states in reactions with the charged particles emission makes it possible to get information on the exciting levels’ structure in the continuous and discrete regions of excitation as well as on the mechanisms of the nuclear reaction occurrence. Therefore, our work aims to investigate the production yields of...
Zirconium-89, with a half-life of 3.3 days, is one of the most promising radioisotopes for nuclear imaging based on monoclonal antibodies (Immuno-PET). Immuno-PET studies require that the half-life of the diagnostic radioactive isotope coincide with the biological half-life of the carriers (monoclonal antibodies), which exceeds 24 hours and averages 2-6 days. Thus, the half-life of 89Zr...
The study of the cross-sections and yields of (γ,p)-reactions allows one to obtain information on the structure of excited levels in the continuous and discrete regions of excitation and the mechanisms of the nuclear reactions’ occurrence. Our work aims to study the yields of Ta-185,183,182 in reactions with the proton emission for irradiated targets by the bremsstrahlung gamma quanta with...
The present work reports the analyses of the experimental angular distributions of $\alpha+^{116,122,124}$Sn elastic scattering in terms of the non-monotonic (NM) and modified single-folded (MSF) potentials. These two types of optical model (OM) potentials have enjoyed success in explaining the $\alpha$-induced elastic scattering and non-elastic processes on several targets [1-4]. The NM...
Decay branching ratio of main and excited state of $^{11}$B in the interaction of neutron and $^{10}$B in energy between 1 and 6 MeV is studied. The experiment is performed at the photoneutron source of the Institute for Nuclear Research of Russian Academy of Sciences. Neutron detector based on the $^{10}$B-layer which served as both target and cathode of wire chamber for detecting secondary...
Fusion cross sections $\sigma_{\rm{fus}}$ for the strongly bound nucleus ${}^{4}$He and the weakly bound nuclei ${}^{6,8}$He have differences in the width of the main maximum of the barrier distribution function $D(E) = d^2 \left( {E\sigma _{{\rm{fus}}} } \right)/dE^2$ [1] near the Coulomb barrier (see Fig. 1). It indicates the differences in the mechanisms of interaction of these...
Upgraded evaluation of integral cross sections of 6Li(d,p0), 6Li(d,p1), 6Li(d,p2), 6Li(d,p4) reactions was obtained in our SaBa (SarovBase) library due to appearance of new experimental data. Data were derived from the results of our experimental studies of 6Li+d reaction channels at 4 to 10 MeV deuteron energy Ed [2]. The reliability of the obtained data was confirmed by the fact that the sum...
The occurrence of lightning is preceded by the fast development of electron avalanche in electric fields with strengthof about ~ 300 kV/m [1]. The growth of avalanche in number of relativistic electrons ensures an energetic terrestrial gamma-ray bursts, that can ensure the photonuclear reactions on atmospheric isotopes (with significant cross sections for hard photons ${E_{\gamma}}$ =20-60 MeV...
$\quad$ Knowledge of the asymptotic normalization coefficients (ANC) for the resulting single-particle bound configurations in the final nucleus (or nuclear vertex constants which differ only by a multiplier from ANCs) [1], plays a crucial role in the calculations of direct nuclear-astrophysical processes of radiative capture [2].
$\quad$ Particularly, to extrapolate the astrophysical S...
The differential cross sections of elastic and inelastic scattering of deuterons on 11B nuclei with excitation of low-lying states of 0.0 MeV (3/2$^-$), 4.445 MeV (5/2$^-$) and 6.74 MeV (7/2$^-$), as well as the reaction (d,t) with transitions to the ground (0$^+$) and excited states with energies of 0.718 MeV $(1^+),$ 1.74 MeV (0$^+$, T = 1), and 2.15 MeV (1$^+$) have been measured at an...
Studies of the cross-sections and yields of photonuclear reactions with production of 12B(T1/2 = 20.2 ms) and 12N(T1/2 = 11.0 ms) are interesting both for development of ideas about nuclear reactions with nuclei-products near the boundaries of stability to nucleon-emission, and for detection of hidden explosives and drugs (see, e.g., [1]) with registration of 12B- and 12N- activities.
In [2,...
Exclusive study of Pre-Equilibrium Emission of Alpha Particles in Alpha Induced Reactions at Moderate Excitation Energy
Avinash Agarwal1*, and Manoj Kumar Sharma2
1 Department of Physics, Bareilly College, Bareilly, MJPR University, Bareilly – 243001 INDIA
2 Department of Physics, Shri Varshney College, Aligarh – 202 001 INDIA
* Email: avibcb@gmail.com
During the past few decades, the...
Experimental measurements of angular and energy distributions of fission neutrons $n(\theta,E)$ per fission event were carried out in [1-4] assuming that $n(\theta,E)=n_{ev}(\theta,E)+n_{sc}(\theta,E)$, where $E$ is asymptotic kinetic energy of a neutron, $\theta$ is angle between the directions of the outgoing neutrons and the light fission fragment, $n_{ev}(\theta,E)$ is number of prompt...
The angular distributions for the emission of deuterons in the 45Sc(3He,d)46Ti reaction were measured; based on the change in the energy of deuterons, we determined the cross sections for population of the ground and excited states of the 46Ti nuclei formed in this reaction at energy 29 MeV of the 3He bombarding particles. The measured angular distributions for the excited states of the 46Ti...
A value of a neutron-neutron scattering length was obtained in different experiments. It can be observed that there is a difference in values of a neutron-neutron scattering length ann (in the range from –16 to –22 fm). In [1] it was suggested that such difference may be explained by influence of 3N-forces. It can be assumed that pp scattering length (or energy of $^{1}$S$_{0}$ virtual...
Fission of actinide nuclei produces fast neutrons, mainly “prompt” neutrons (PNs), but also (2%) “delayed” neutrons (DNs with different half-lives T1/2). Usually, for the sake of convenience, DNs are divided into 6–8 groups according to their T1/2-values at approximately 0.2 s < T1/2 < 56 s (see, e.g., [1]). But there are some indications that it is necessary to search for short-lived DNs with...
The nuclear $^4$He + $^2$H system is of great importance to nuclear astrophysics. Radiative capture proceeding in this system is responsible for production of the $^6$Li nuclei during the primordial nucleosynthesis. In this work, the $^4$He + $^2$H radiative capture is considered from the microscopic viewpoint within a developed approach [1, 2] based on clustering aspects of nuclear structure...
