The interaction of two colliding deuterium plasma flows propagating in opposite directions across the magnetic field and having opposite directions of the polarization fields has been experimentally studied. The plasma flows with densities up to 10(16) cm(-3) stop and a velocity of up to 2 x 10(7) stop cm/s were formed using discharges initiated in crossed E x H fields. Each discharge operated at an electric power of up to 300 mW and a discharge current up to 100 kA. The results of measurements of the equivalent capacitance of polarized plasma flows were used to estimate the transverse permittivity of plasma. The rate of depolarization in colliding flows was determined. The frequency and energy characteristics of a plasma LC circuit formed by colliding flows were estimated. The temporal modulation of plasma density in the flows was measured.

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 (2201312 keV) has been considered. The preliminary experimental data on measurement of the astrophysical S factor for the dd reaction (dd 2192 3He + n (2.5 MeV)) at average deuteron collision energies E col = 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.

Using the plasma accelerator based on the pulse Hall ion source, the first measurements of the astrophysical S-factor of the d+d->³He+n reaction were performed for deuteron energies 9.1 and 9.9 keV. The observed values of the S-factor and effective cross sections σ_dd for dd reaction are in agreement with the results obtained by us earlier in the experiments at liner plasma accelerators (in configuration of both direct and inverse Z-pinch). The preliminary results have confirmed the fact that the proposed technique can be effective to study nuclear reactions between light nuclei in the astrophysical energy region.

The results of the investigations of two colliding deuterium plasma flows propagating in opposite directions across the magnetic field and having opposite directions of the polarization fields has been presented. The plasma flows with densities up to 10¹⁶ cm^-3 stop and a velocity of up to 2·10⁷ cm/s were formed using discharges initiated in crossed E x H fields. Each discharge operated at an electric power of up to 300 mW and a discharge current up to 100 kA. The rate of depolarization in colliding flows was determined. The frequency and energy characteristics of a plasma LC circuit formed by colliding flows were estimated. The temporal modulation of plasma density in the flows was measured.

We discuss the possibility of using a plasma accelerator based on a pulsed Hall ion source to study the characteristics of pd, dd, and d³He reactions in the astrophysical energy range (2 - 12 keV). The preliminary experimental data on measurement of the astrophysical S-factor for the dd reaction (dd ->³He + n (2.5 MeV)) at the deuteron collision energies from the range 4 - 12 keV and the deuteron beam energy spread FWHM = 18agreement with the results of the experiments carried out by us previously using linear plasma in the inverse Z-pinch configuration.

A project of an experiment on measurement of the cross sections of radiative thermal neutron capture by He-3 nuclei with production of one and two gamma quanta is presented.

Formation and dynamics of the hydrogen liner, and nuclear reaction (pd ->†’³He + γ (5.5 MeV)) in the keV collision energy range were studied using the inverse Z-pinch configuration. The fundamental properties of light nuclei reactions in keV energy range are of importance for checking the validity of the models in basic physics and astrophysics. Two experimental techniques were proposed and tested for recovering the energy distribution of the protons in the expanding plasma liner. The first technique is based on the measuring the proton flow density, and the second on the measuring the H_α -plasma radiation of the exited neutrals in the expanding plasma liner. 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. This approach was used to get the estimates of the upper limits for the astrophysical S-factor and effective cross section of the pd-reaction for proton-deuteron collisions in the energy range of 2.7-16.7 keV.

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).

The pd reaction (pd -> He-3 + gamma (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.

The properties of photomultiplier tubes operating in the gating mode as components of scintillation detectors were investigated in high-power pulsed electromagnetic and nuclear radiation fields. Photomultiplier tubes with Venetian blind and linear focused dynode systems were considered. The diagrams of the gating circuits for the photomultipliers based on high-voltage dividers of the active and resistor types are presented. The results of our investigations are significant for a large number of experiments involving discrimination in time between the preceding background radiation and the useful signal.

Dynamics of formation and evolution of the hydrogen liner in the inverse Z-pinch configuration, and nuclear reaction pd -> ³He + 5.5 MeV gamma ray in the ultra low energy range of collision energies were studied at the pulsed power generator MIG. 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 have been obtained.

in russian

The results are presented of the investigation of the designed gating circuits to operate the photomultipliers work of the scintillation detectors in electromagnetic and nuclear radiation powerful pulsed fields. Here are considered two variants of high-voltage dividers (HVD) PMT: a resistive and a transistor ones. The experimental data are actual for the wide range of experiments with the essential suppression of the scintillation detector intensive background load during the time interval of ”useful” events detection. The designated gating PMT circuits could be succesfully used while studying rare processes at a high-intensity background process level.

in russian

Results are presented from experimental studies of the parameters of two counterpropagating (colliding) plasma flows generated by discharges in crossed electric and magnetic fields. It is shown that the conversion efficiency of the energy deposited in the discharges into the energy of directed plasma flows is 0.3-0.6. For discharge current pulses with a duration of approx. 10 μ s, the energy flux density in the plasma flow reaches approx. 10 J/cm² and the total energy of the flows is on the order of 300 J. The density of deuterons in flows is approx. 10¹⁵ cm^-3 , and the flow velocity is <=2×10⁷ cm/s. The total number of particles carried by flows is about 10¹⁹. The possibility of using counterpropagating plasma flows to study reactions involving light nuclei (dd, pd, dt, and d-He reactions) in the range of ultralow collision energies is discussed. (12 References).

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, &tau = 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 (H_&alpha and H_&beta 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 E = 3.69 keV was equal to S(E = 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 &sigma ^dd(E = 3.69 keV) = (1.33 +- 0.41) 10^-30 cm².

A method and results of measurements are presented of the ion energy distribution in a deuterium liner accelerated in the inverse Z-pinch, in which the plasma is accelerated electrodynamically from the liner axis. Knowledge of the deuteron energy distribution is of primary importance for the correct interpretation of the experimental results from the study of the dd-reaction in the range of infralow energies with the use of a liner plasma. Experiments were carried out in a high-current pulsed accelerator (I=950 kA, &tau =80 ns) at the Institute of High-Current Electronics of the Siberian Division of the Russian Academy of Sciences (Tomsk, Russia). In the initial state, the liner is a supersonic hollow deuterium jet 32 mm in diameter and 20 mm in length. The liner parameters were measured with the help of optical detectors of H_&alpha and H_&beta deuterium lines and magnetic probes arranged in a radial direction (along the direction the liner expansion). In addition, scintillation spectrometers and BF₃ counters were used to measure the intensity of the neutron flux produced in the d+d to 3He+n reaction. The results obtained by simultaneously analyzing the data from magnetic probes, optical detectors, and neutron detectors point to the possibility of using a rather simple method for measuring the parameters of the liner accelerated up to energies of 3-6 keV. (16 References).

A possibility of using a thermal neutron detector in the high gamma -quantum and bremsstrahlung fields is considered in the paper. The design of the thermal neutron detector consisting of 10 counters filled with 3He under a pressure of 2 atm and enclosed in a polyethylene moderator is described. The results of measuring the neutron recording efficiency and neutron lifetimes by this detector exposed to a neutron flux from the dt-reaction and from Cf-252 and Pu-Be sources are reported. The thicknesses of the polyethylene moderator and the Pb layer used for suppression of the background in the fields of powerful electromagnetic radiation are optimized. (18 References).

This work is a part of a continuing research on measuring dd- reaction cross sections in keV energy range using accelerated ion flow in the liner of the Z-pinch generator. The knowledge of the ions energy distribution in the accelerated liner is crucially important for calculation of cross section. Diagnostics and the first results on the measurement of the energy distribution of the liner ions in the inverse Z-pinch geometry are described. Experiments were fulfilled in HCEI (Tomsk, Russia) at the nanosecond pulsed generator of 1 MA, 80 ns pulse. The spatially and time resolved liner dynamics and its radiation were measured with a set of light detectors (LDs), placed at various radii registering H/sub alpha / and H/sub beta / deuterium lines, and with B-dot probes, measuring the dynamics of the current carrying plasma liner. Processing of the LDs signal waveforms based on assumption of ordered ion flow between the LDs provided compatible information on the ion energy distribution. The neutron TOF measurements provided data on the high energy deuterons flows, responsible for the main neutron output. These experiments substantiate potential of using optical plasma diagnostic, which in combination with conventional electro-physical and neutron diagnostics could significantly improve reliability of dd-reaction cross-section measurement. (5 References).

The experimental results of measurements of the astrophysical S-factor for dd-reaction at keV-energy range collision energies using liner plasma technique are presented. The experiments were carried out at the high current generator of the Institute of High-Current Electronics in Tomsk, Russia. The measured values of the S-factors for the deuteron collision energies 1.80, 2.06 and 227 keV are S = (114+-68), (64+-30), (53+-16) b.keV, respectively. The corresponding cross sections for dd-reactions, described as a product of the barrier factor and measured astrophysical S-factor, are &sigma (E=1.80 keV)=(4.3+-2.6).10^-33 cm²; &sigma (E=2.06 keV)=(9.8+-4.6).10 ^-33 cm²; &sigma (E=2.27 keV)=(2.1+-0.6).10^-32 cm². (36 References).

Experimental results are presented that were obtained by measuring the astrophysical S factor for dd interaction at very low deuteron collision energies by using the liner-plasma technique. (38 References).

This paper is devoted to examination of the possibility of using a deuterium inverse Z-pinch for investigation of the dd reaction at ultralow deuterium collision energies. The experiment was carried out at the Institute of High-Current Electronics (Tomsk) using the high current accelerator (the current pulse amplitude is 850 kA, the high-voltage pulse duration is ˜80 ns). The characteristic data of the deuterium liner accelerated by the inverse Z-pinch process up to (2.8-7.2)*10⁷ cm/s were measured for the first time. The type and values of gamma and neutron radiation that occurred during liner acceleration process were examined. The application of fast scintillator neutron detectors with definite size and a deuterium target located at distances more than 140 mm from the liner axis was demonstrated to allow reliable time separation of useful events from background events. (23 References).

Experimental results on measurement of dd-reaction cross sections in the energy range of 0.1-1.5 keV using the Z-pinch technique are presented. The experiment was fulfilled at the high current generator of the High-Current Electronics Institute, city of Tomsk, Russia. The dd-fusion neutrons were registered by time-of-flight scintillator detectors and BF₃ detectors of thermal neutrons. The estimates were obtained at 90% of the confidence level for the upper limits of the neutron-producing dd-reaction cross sections for average deuteron collision energies of 0.11, 0.34, 0.37 and 1.46 keV. These results substantiate feasibility to get a cross section magnitude for dd-reaction in the range of the collision energy of 0.8-3 keV using similar technology at the pulse current level of 2-3 MA. (53 References).

To study nuclear reactions d+d->t+p, p+⁶Li->⁷Be+γ, d+³He->p+⁴He, etc. at very low energies (50 eV - 1000 eV) by means of liner plasma the experimental programme is proposed. The products of nuclear reactions are proposed to be registered with polymeric track detectors on the basis of CR-39, NaI(Tl) scintillation detectors, etc. The lower limit of cross sections estimated for dd-reaction is σ= 10^-38 cm². The investigations are proposed to be carried out in the High Current Electronics Institute (Tomsk, Russia).