A modification of the neutron activation method for the diagnostics of deuterium–tritium plasma of powerful pulsed fusion facilities is proposed. The method allows one to determine the effective plasma ion temperature by width of the spectral distribution of generated DT neutrons. The physical basis of the method and conditions for its implementation are described and methods for the calibration of measuring channels sensitivity are considered.

Computational studies aimed at improving the accuracy of measurements performed using neutron generators with a tritium target were performed. A measurement design yielding an extremely narrow peak in the energy spectrum of DT neutrons was found. The presence of such a peak establishes the conditions for precise energy calibration of fast-neutron spectrometers.

A pulsed soft-X-ray detector consisting of a high-current photomultiplier tube and a thin-film polystyrene-based plastic scintillator was developed. Its characteristics were investigated by detecting quasimonochromatic 0.84-keV X-ray pulses. The dependence of the scintillator light output on the photon energy flux density was obtained. The average effective thickness of the surface non-scintillating (“dead”) layer affecting the spectral response of this detector type was estimated.

The inverse skin effect and its influence on the dynamics of high-current Z-pinch and plasma focus discharges in deuterium are analyzed. It is shown that the second compression responsible for the major fraction of the neutron yield can be interpreted as a result of the inverse skin effect resulting in the axial concentration of the longitudinal current density and the appearance of a reversed current in the outer layers of plasma pinches. Possible conditions leading to the enhancement of the inverse skin effect and accessible for experimental verification by modern diagnostics are formulated.

The results of a study of radiation characteristics of a high-current pinch discharge of the plasma-focus type in the region of soft and ultrasoft X-rays are presented. Experiments were performed at a moderate energy of discharges in a mixture of H2 and Ne. It was shown that a comparatively narrow spectrum region of the generated radiation, which corresponds to the line emission of lithium-like ions Ne7+ with an average effective quantum energy Eeff≈ 0.16 keV, can be selected. The Ne7+ emission fluence was (0.2–1.0) × 1012 quant/cm2 per pulse with a duration τ0.5 = 40–100 ns. The results obtained demonstrate the feasibility of using such discharges in laboratories as pulse sources of quasi-monochromatic ultrasoft X-rays.

The systems with compression of preheated magnetized plasma (MAGO/MTF) are promising regarding the achievement of the thermonuclear fusion threshold. A version of this system has been realized in VNIIEF where a dense high temperature DT-plasma was obtained with a lifetime of few microseconds, being a source of high power neutron and X-ray pulses. For diagnostics a research method for spatial-temporal parameters in the soft X-ray generation plasma region, which is formed in the MAGO chamber, has been developed. The method is based on soft X-ray plasma image formation with the help of a pinhole camera and its consequent conversion to an optical image. Optical plasma image registration is made with the use of an electron optics multi-frame recording system. For the first time for the conditions of MAGO explosive experiments the two-dimensional plasma images for three sequential intervals of discharge, corresponding to a maximum soft X-ray yield was obtained. The position, shape and typical sizes of the plasma region are determined. The development of the method for plasma research in MAGO/MTF experiments seems possible.

Summary form only given, as follows. The systems with compression of magnetized heated plasma (MAGO/MTF) are promising regarding the achievement of the thermonuclear fusion threshold. A version of this system has been realized in VNIIEF where a dense high temperature DT-plasma was obtained with the lifetime of some microseconds, being a source of high-power neutrons and X-ray pulses. The research method of spatial-temporal parameters in the soft X-ray generation plasma region, which is formed in the discharging camera of the MAGO-system, has been developed for diagnostics. The method is based on the soft X-ray plasma image formation with the help of a pinhole camera and its consequent conversion to an optical image. Optical plasma image registration is made with the use of an electron optical multi-frame recording system. For the first time in the conditions of the MAGO explosive experiments the two-dimensional plasma image for three sequential intervals of discharge, corresponding to maximum soft X-rays yield was obtained. The position, shape and typical sizes of the plasma region are determined. The evolution of the described method for plasma parameters research in MAGO/MTF experiments is seemed to be very perspective.

For future research in the area of thermonuclear fusion and physics of high-energy-density VNIIEF is conducting the development of the multifunctional electrophysical explosive complex "EMIR". It is supposed, that with the use of this complex the conditions of thermonuclear ignition in high temperature plasma (/spl sim/0.3 keV) with a lifetime about several nanoseconds, forming during the electrodynamic compression of cylindrical plasma shells in Z-pinch geometry, will be achieved. One of the main problems to be resolved for realization broad-scale experiments on the complex "EMIR" are the development of methods for diagnostics of the processes, taking place in its separate devices. Along with the development of the methods intended to measure electrotechnical parameters of the magnetic energy source modules the development of methods for radiation diagnostics of plasma load and cavity with the thermonuclear target is of primary importance. In the report the measurement methods of the main power module parameters, including plasma current breaking, systems of the soft X-ray generation and the thermonuclear target are considered. The sensitivity and resolution of the methods are pointed out. The proposed measurement methods are adapted to conditions of explosive experiments with increased level of electromagnetic noise and may be tested on different laboratory installations. The realization of experiments with such methods will promote the obtaining of important information about dynamics of processes, which take place in the multifunctional electrophysical explosive complex "EMIR".

Experimental results of the soft X-ray spectra investigation from a hot plasma produced by impulse discharge of a dense plasma focus in pure neon are presented. The spectral-energy characteristics of X-ray emission were measured in the photon energy range of 0.5-5.0 keV with the help of thin absorber filters set and silicon semiconductor p-i-n detectors SPPD11-04. A study was made at the filling gas pressure P/sub Ne/=2.0-6.0 Torr and at the stored capacitor bank energy W=15-21 kJ. A high degree of monochromatization for the soft X-ray emission (/spl sim/90 %) was obtained. According to the experimental data characteristic plasma electron temperature in the time duration of X-ray pulse /spl tau//sub 1/2/=10-100 ns has been estimated as T/sub e//spl sim/0.2-0.3 keV. The plasma parameters obtained are compared with the results of computer simulation of the emission process.

The construction and characteristics of a pulsed monoenergetic soft X-ray source (E = 0.848 keV) are presented. The source is based on the principle of conversion of the X-ray radiation emitted from a heavy-current discharge of plasma focus, and allows obtaining a ''spectral purity'' of the emitted radiation close to 100%. The radiant flux density is about 10(17) photon/(cm(2) s), which is sufficient for the calibration of X-ray detectors with sensitivities not lower than about similar to 10(-19) (C cm(2))/photon.

A circuit for passive charge integration is presented. The circuit is combined with a device to suppress the noninformative part of the signal from the light-pulse detector, which is based on an SNFT3 photomultiplier tube. The charge integration time varies from units of nanoseconds to units of microseconds. The device to suppress noninformative part of the signal consists of two switches based on a 2T312B transistor and OU103B optocoupler. It enables one to reduce the sensitivity of the photomultiplier by a factor of 10(4) for greater-than-or-equal-to 500 musec after the informative part of the signal has passed through.