V. V. Gerasimov

Measurement of the astrophysical S factor for dd interaction at ultralow deuteron-collision energies using the inverse Z pinch

This paper is devoted to measurement of the astrophysical S factor and cross sections of the d + d → 3He + n reaction at ultralow deuteron-collision energies. Formation of the flow of the accelerated deuterons incident on the CD2 solid-state target was made within the scheme of the inverse Z pinch. The liner in the initial state was a hollow supersonic deuterium jet of radius of 15 mm and length of 20 mm. The experiment was carried out at the pulsed high-current accelerator (I=950 kA, τ=80 ns) of the Institute of High-Current Electronics (Tomsk, Russia). Measurement of the deuteron energy distribution was performed through an analysis of the time distributions of the intensity of the liner radiation (Hα and Hβ lines) generated during the liner radial movement from the axis. Recording of this radiation was carried out by optical detectors placed along the direction of the liner moving from its axis. The measured value of the astrophysical S factor for the dd reaction at the average deuteron collision energy Ecoll=3.69 keV was equal to S(Ecoll=3.69 keV)=58.2±18.1 keV b. The dd-reaction cross section calculated using the found value of the S factor and known representation of the reaction cross section as the product of the barrier factor and the astrophysical S factor was σddn(Ecoll=3.69 keV)=(1.33±0.41)×10−30 cm2.

Study of the pd reaction at ultralow energies using hydrogen liner plasma

AbstractThe pd reaction (pd → He + γ (5.5 MeV)) is studied in the astrophysical energy collision range of protons with deuterons using the hydrogen liner in the inverse Z-pinch configuration at the pulsed power generator MIG (HCEI, Tomsk). Fundamental characteristics of this and other light-nucleus reactions at ultralow energies are important for problems of basic physics and astrophysics. The knowledge of the energy distribution of the nuclei participating in these reactions is important due to their exponential type of dependence on the collision energy. Two experimental techniques were designed and tested for recovering the energy distribution of liner protons incident on the CD2 target by using optical detectors and ion collectors. It is shown that the combined use of these two techniques could provide relevant information on the energy distribution of the accelerated protons in the liner. The estimates of the upper limits for the astrophysical S factor and effective cross section of the pd reaction in the proton-deuteron collision energy range of 2.7–16.7 keV are obtained:

Using a hall accelerator to investigate d(d, n)3He and d(p, γ)3He reactions in the astrophysical energy region

\bar S_{pd} (E_{pd} = 10.2 keV) \leqslant 2.5 \times 10^{ - 7} MeV b;\overline \sigma _{pd} (2.7 \leqslant E_{pd} \leqslant 16.7 keV) \leqslant 4 \times 10^{ - 33} cm^2

Neutron Emission Generated in the Collision of Plasma Flows in the Presence of an External Magnetic Field

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Method of determination of muon-catalyzed fusion parameters in H-T mixture

The possibility of using a plasma accelerator based on a pulsed Hall ion source to study the characteristics of pd, dd, d3He, 3He, and4He reactions in the astrophysical energy range (2–12 keV) has been considered. The preliminary experimental data on measurement of the astrophysical S factor for the dd reaction (dd → 3He + n (2.5 MeV)) at average deuteron collision energies Ecol = 4.5 and 4.95 keV and the deuteron beam energy spread FWHM = 18% are reported. The found value of the S factor is in agreement with the results of the experiments carried out by us previously using linear plasma in the inverse Z-pinch configuration.

Study of the d (d, n)3He reaction in the astrophysical energy region with the use of the Hall accelerator

We present new results on astrophysical S-factors and cross sections for reactions dd → 3He + n(2.5MeV) and pd → 3He + γ (5.5MeV) in ultra-low energy ranges 2.3–6.2 keV and 8.3–10.1 keV, respectively. Experiments were performed with proton and neutron beams produced by a pulsed Hall accelerator (Nuclear Physics Institute, Tomsk) and deuterated polyethylene (CD2) and frozen heavy water (D2O) targets. Within measurement errors, our results are consistent with the literature’s experimental results on pd and dd reactions for the given energy ranges, where D2O or gaseous deuterium targets were used.

Study of the pd reaction in the astrophysical energy region using the Hall accelerator

This work is devoted to measuring of the values of the astrophysical S-factors and electron screening potential energy for a d(d,n)3He reaction occurring at ultralow energies in zirconium deuteride ZrD2 (3.5–7.0 keV) and heavy water D2O (2.2–6.0 keV). The experiment was performed on the Hall pulsed plasma accelerator at the TPU Nuclear Physics Institute (Tomsk) with ZrD2 and D2O targets produced by the magnetron sputtering of zirconium in a deuterium environment and heavy water freezing-out on a copper support, respectively. A χ2 analysis of the dependence of the neutron yields and astrophysical S-factors for the dd reaction on the deuteron collision energy E revealed that the upper bounds of the electron screening potential energy for interacting deuterons in ZrD2 and D2O and of the astrophysical S-factors at the deuteron collision energy E = 0 were Ue(ZrD2) < 30 eV, Ue(D2O) < 25 eV, S(0) = (57.2 ± 3.9) keV · b (ZrD2), S(0) = (58.6 ± 3.6) keV · b (D2O) at the 90% confidence level.

Kinetics of muon catalyzed fusion processes in solid H/D mixture

Results are presented from experimental studies of the neutron emission generated in the collision of deuterium plasma flows produced in discharges in crossed E × H fields and propagating in opposite directions in a neutral gas across an external magnetic field. It is shown that the interaction of oppositely propagating deuterium plasma flows gives rise to the generation of soft X-ray emission and neutron emission from the dd reaction (dd → 3He + n) and is accompanied by an almost complete depolarization of the flows and rapid variations in the magnetic field (at a rate of ∼1011 G/s). The measurements were performed at energies and velocities of the flows of up to 600 J and 3.5 × 107 cm/s, respectively. The plasma density in each flow was ∼1015 cm−3. The upper estimates for the astrophysical S factor and the effective cross sections of the dd reaction obtained from our measurements are compared to theoretical calculations and to the results of experiments performed in the MIG high-current accelerator (Institute of High-Current Electronics, Russian Academy of Sciences, Tomsk).