The extremely neutron-rich system H6 was studied in the direct H2(He8,He4)H6 transfer reaction with a 26A MeV secondary He8 beam. The measured missing mass spectrum shows a broad bump at ≈4-8 MeV ...above the H3+3n decay threshold. This bump can be interpreted as a broad resonant state in H6 at 6.8(5) MeV. The population cross section of such a presumably p-wave state (or it may be few overlapping states) in the energy range from 4 to 8 MeV is dσ/dωc.m.≃190-80+40μb/sr in the angular range 5°<θc.m.<16°. The obtained missing mass spectrum is practically free of H6 events below 3.5 MeV (dσ/dωc.m. 5μb/sr in the same angular range). The steep rise of the H6 missing mass spectrum at ≈3 MeV allows us to derive the lower limit for the possible resonant-state energy in H6 to be 4.5(3) MeV. According to the paring energy estimates, such a 4.5(3) MeV resonance is a realistic candidate for the H6 ground state (g.s.). The obtained results confirm that the decay mechanism of the H7 g.s. (located at 2.2 MeV above the H3+4n threshold) is the "true"(or simultaneous) 4n emission. The resonance energy profiles and the momentum distributions of fragments of the sequential H6→H5(g.s.)+n→H3+3n decay were analyzed by the theoretically updated direct four-body-decay and sequential-emission mechanisms. The measured momentum distributions of the H3 fragments in the H6 rest frame indicate very strong "dineutron-type"correlations in the H5 ground state decay.
The extremely neutron-rich system H7 was studied in the direct H2(He8,He3)H7 transfer reaction with a 26 AMeV secondary He8 beam Bezbakh et al., Phys. Rev. Lett. 124, 022502 ...(2020)PRLTAO0031-900710.1103/PhysRevLett.124.022502. The missing mass spectrum and center-of-mass angular distributions of H7, as well as the momentum distribution of the H3 fragment in the H7 frame, were constructed. In addition, we carried out another experiment with the same beam but a modified setup, which was cross-checked by the study of the H2(Be10,He3)Li9 reaction. A solid experimental evidence is provided that two resonant states of H7 are located in its spectrum at 2.2(5) and 5.5(3)MeV relative to the H3+4n decay threshold. Also, there are indications that the resonant states at 7.5(3) and 11.0(3)MeV are present in the measured H7 spectrum. Based on the energy and angular distributions, obtained for the studied H2(He8,He3)H7 reaction, the weakly populated 2.2(5)-MeV peak is ascribed to the H7 ground state. It is highly plausible that the firmly ascertained 5.5(3)-MeV state is the 5/2+ member of the H7 excitation 5/2+-3/2+ doublet, built on the 2+ configuration of valence neutrons. The supposed 7.5-MeV state can be another member of this doublet, which could not be resolved in Bezbakh et al. Phys. Rev. Lett. 124, 022502 (2020)PRLTAO0031-900710.1103/PhysRevLett.124.022502. Consequently, the two doublet members appeared in the spectrum of H7 in the work mentioned above as a single broad 6.5-MeV peak.
The extremely neutron-rich systems 7H, 6H were studied in the 2H(8He, 3He)7H and 2H(8He, 4He)6H proton and deuteron pickup reactions with a 26 AMeV secondary 8He beam produced at the new ACCULINNA-2 ...fragment separator. In addition, the same proton and deuteron pickup reactions were generated using the 42 AMeV 10Be beam, and the population of low-lying 9Li and 8Li states was measured in reactions 2H(10Be,3He)9Li and 2H(10Be,4He)8Li, respectively. The latter were used as reference measurements in order to check the setup calibration over the excitation energy of 7,6H and to determine the real experimental energy resolution which was compared with Monte Carlo calculations. The corresponding results obtained for the superheavy hydrogen systems 7H, 6H are presented and discussed. Typical excitation spectra of the 9Li and 8Li nuclei are also shown.
The one-neutron transfer
2
H(
9
Li,
p
)
10
Li reaction has been investigated at 29
A
MeV incident energy at the ACCULINNA-2 facility (Flerov Laboratory of Nuclear Reactions, Joint Institute for ...Nuclear Research). The setup has been used in order to detect the recoil protons at backward angles in coincidences with the outgoing
9
Li and neutrons from the
10
Li decay at forward angles. This setup allows to study the
10
Li emitted in the crucial region at forward angles in the center of mass. The preliminary results in the part of the analysis of double proton–
9
Li coincidence are reported.
Investigation of the
7
H-system in the experiment conducted at the fragment separator ACCULINNA-2 in the
8
He(
2
H,
3
He)
7
H reaction requires to detect the recoil
3
He ions with energy down to 6 ...MeV. For this purpose two
particle telescopes are used, with each telescope having in front a thin (20-μm) Si strip detector (
). The maps of thickness heterogeneity of the thin detectors were determined by measuring the energy losses of the
226
Ra α-particles. The adopted thickness normalization method provides a good identification of the
3
He nuclei being recorded in the presence of a high
4
He background. Two approaches were used for calculating the energy losses of the identified
3
He and
4
He reaction ejectiles and reconstructing their energy values available at the exit from the deuterium target. The developed techniques were applied for the
7
H missing-mass reconstruction.
In the recent work Nikolskii et al., Phys. Rev. C 105, 064605 (2022) the 2H(8He,4He)6H reaction was used for the study of the extreme neutron-rich 6H isotope. A broad bump was observed in the ...measured 6H spectrum interpreted as the broad overlapping ground and some low-lying states of this nuclide. There could be certain doubts in the interpretation of this work: in conditions of the limited phase space it is not impossible that the structure in the missing mass spectrum of 6H is actually induced by the resonant states populated by some other channels opened in the 8He+2H interaction. This work provides a body of the evidence for the correct channel identification and for the absence of the 6H resonances at energy ET = 0 − 3.5 MeV above the 3H+3n decay threshold. In addition the first strong experimental evidence is given that the 6H → 5H*+n → 3H+3n sequential decay is the dominating 6H decay channel.
Domanic type deposits generally is abundant in Tatarstan Republic and other territories. They are feature with oil-source rocks (black shales), which partly generated hydrocarbons. However, due to ...their high hydrocarbon contain, domanic type deposits construing as unconventional reservoir rocks, that may be commercial significant. Based on Russian and foreign experience in the development of such deposits, the prospects for their exploitation are associated with the searching for formations with increased reservoir properties and light oil.
In this work we are analyzed the stratigraphic distribution of domanic type deposits in the Kama-Kinel system of depressions and beyond them. It is shown that such deposits in the Kama-Kinel system of depressions have a thickness about 300 m and cover the stratigraphic range from semiluk horizon of the Frasnian stage to Tournaisian stage. But out of depressions these rocks occurred only in semiluk horizon. The reason of it is high dissection of the bottom of the Domanic sedimentation basin in the Late Frasnian-Tournaisian ages due to the evolution of the Kama-Kinel system of depressions in the east of the Russian Plate.
The results of our own research show that carbonate and carbonate-siliceous rocks enriched in organic matter are the most common lithotypes in the Domanic type deposits. Also, we constantly found carbonate breccias and less secondary dolomites in the studied geological columns. In the last two types of rocks, we found higher values of porosity, openness, and a lighter composition of hydrocarbons. Based on the results of the author’s research and the literature observation, it follows that the development of carbonate breccias and secondary dolomites will be in the sides of the Kama-Kinel system of depressions. We consider that they are as the most promising objects for the search for industrial profit in the Domanic type deposits.
Abstract
Oil-bearing carbonate complexes of the Bashkirian stage of low-amplitude brachianticlinal structures on the western slope of the South Tatar arch are considered. It has been established that ...the prospects for oil production are associated with the upper parts of the sections, where layers of algal-foraminiferal limestones - packstone occur, overlain by dense clayed mudstone-wackestone limestones. Oil deposits of the dome type, hydrodynamically isolated, are under the pressure of regional or bottom waters. Cap rocks, reservoir rock, water-oil contacts are clearly distinguished in the structure of deposits. The formation of the main elements of oil fields occurred at the stage of sedimentation due to eustatic fluctuations in the level of the epicontinental sea basin. At the stage of transgression, the formation of future reservoir rocks took place, at the stages of regression - cap rocks. The reservoir rocks acquired high capacitive-filtration properties during the period of migration of water-oil fluids. At this time, the dissolution of micritic calcite cement took place, the removal of the dissolved substance outside the reservoir bed, the filling of the void space with oil, and the displacement of residual water to the wings of uplifts. The next stage of transformation of reservoir rocks is associated with the processes of natural waterflooding of oil deposits. The penetration of regional pressure water into the oil reservoir contributed to the formation of local zones of water-oil contacts. Due to the oxidation of hydrocarbons inside the oil deposits in the OWC zone, bituminous and water-bearing subzones were formed. In the first one, intensive leaching of calcite occurred with the simultaneous formation of patchy-banded segregations of calcitized rocks, healing of cavern cavities with diagenetic dolomite and anhydrite. In the second subzone, the process of dissolution of bituminous films on the walls of caverns was going on, accompanied by secondary cementation of pre-existing cavities with diagenetic calcite and chalcedony, which determined the light color of reservoir rocks.
THE PURPOSE. Comprehensive study of the effect of direct current electric discharge plasma in a gas-liquid medium of inorganic mixtures in order to obtain gaseous hydrogen. Obtain volt-ampere, ...volt-second and ampere-second characteristics of the discharge at various concentrations of electrolyte. Study the process of electrolysis, breakdown, discharge ignition and discharge flow in a dielectric tube at a constant current. METHODS. To solve this problem, experimental studies were carried out on a model installation, which consists of a power supply system, a discharge chamber, equipment for monitoring and controlling the operation of the installation and measuring the characteristics of an electric discharge. To analyze the stability of the discharge, the time dependences of the voltage ripple and the discharge current were obtained. RESULTS. Experimental studies were carried out between the electrolytic cathode and the electrolytic anode at constant current and at atmospheric pressure with the following parameters: discharge voltage U = 0.1-1.5 kV, discharge current I = 0.02-2.3 A, interelectrode distance l = 100 mm , 1%, 3% and 5% solutions of sodium chloride in tap water were used as electrolytes. CONCLUSION. It is shown that electrical breakdown and ignition of a discharge that is stable in time depends on the conductivity of the gas-liquid medium of the electrolyte. The nature of the current-voltage characteristics depends on the random processes occurring in the gas-liquid medium, which is associated with numerous breakdowns occurring in the gas-liquid medium of the electrolyte, combustion and attenuation of microdischarges, the appearance of bubbles, and the movement of the electrolyte inside the dielectric tube. It is shown that the generation of hydrogen and hydrogen-containing components can occur both at the stage of electrolysis and during discharge combustion. A feature of this method is that electrical discharges in the tube increase the release of hydrogen. In this installation, inorganic and organic liquids of a certain composition and concentration can be used. The results of experimental studies made it possible to develop and create a small-sized installation for producing gaseous hydrogen. Tests have shown that a small-sized plant can be taken as the basis for a industrial plant for the production of hydrogen gas.
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