8 research outputs found
Experimental research of neutron yield and spectrum from deuterium gas-puff z-pinch on the GIT-12 generator at current above 2 MA
The Z-pinch experiments with deuterium gas-puff surrounded by an outer plasma shell were carried out on the GIT-12 generator (Tomsk, Russia) at currents of 2 MA. The plasma shell consisting of hydrogen and carbon ions was formed by 48 plasma guns. The deuterium gas-puff was created by a fast electromagnetic valve. This configuration provides an efficient mode of the neutron production in DD reaction, and the neutron yield reaches a value above 1012 neutrons per shot. Neutron diagnostics included scintillation TOF detectors for determination of the neutron energy spectrum, bubble detectors BD-PND, a silver activation detector, and several activation samples for determination of the neutron yield analysed by a Sodium Iodide (NaI) and a high-purity Germanium (HPGe) detectors. Using this neutron diagnostic complex, we measured the total neutron yield and amount of high-energy neutrons
MCNP calculations of neutron emission anisotropy caused by the GIT-12 hardware
The MCNP6 and MCNPX calculations for the GIT-12 device in Tomsk were performed to determine
the influence of the gas-puff hardware on the neutron emission anisotropy and the neutron scattering rate. A
monoenergetic 2.45 MeV neutron source and F1 and F6 tallies were declared in the simulation input. A comparison
between MCNP results and the measured data was made. Differences between MCNPX and MCNP6
output data were investigated. In the experiment, two nTOF scintillation detectors with the Bicron BC-408
scintillator were used to measure the neutron waveform. Four bubble BD-PND detectors were used to estimate
the amount of neutrons in different places around the neutron source
Evolution of the small ball-like structures in the plasma focus discharge
The experiments were carried out in the PF-1000 plasma-focus device at the maximum current reaching
about 2 MA, at the deuterium or neon filling and with deuterium injected from a gas-puff nozzle placed
on the axis of the anode face. Ball-like structures of diameters of 1–12 mm were identifi ed in interferometric
and XUV pinhole camera frames. We made the statistical description of their parameters. A lifetime of the ball-
-like structures was in the range from 30 to 210 ns, and in some cases even more. These structures appeared
mostly at the surface of the imploding plasma shell and they did not change their position in relation to the
anode end. During the evolution of these structures, interferometric fringes were observed near the surfaces of
the structures only, and their internal parts were initially chaotic (without noticeable) fringes. Subsequently the
number of interferometric fringes increased (the internal ‘chaotic’ area was fi lled with fringes too) and later on
it decreased. The radii of the ball-like structures were mostly increasing during their existence. The maximum
electron density reached the value of 1024 to 1025 m–3. The ball-like structures decayed by absorption inside the
expanded pinch column and/or gradually expired in rare plasma outside of the dense plasma column
Evolution of the small ball-like structures in the plasma focus discharge
The experiments were carried out in the PF-1000 plasma-focus device at the maximum current reaching
about 2 MA, at the deuterium or neon filling and with deuterium injected from a gas-puff nozzle placed
on the axis of the anode face. Ball-like structures of diameters of 1–12 mm were identifi ed in interferometric
and XUV pinhole camera frames. We made the statistical description of their parameters. A lifetime of the ball-
-like structures was in the range from 30 to 210 ns, and in some cases even more. These structures appeared
mostly at the surface of the imploding plasma shell and they did not change their position in relation to the
anode end. During the evolution of these structures, interferometric fringes were observed near the surfaces of
the structures only, and their internal parts were initially chaotic (without noticeable) fringes. Subsequently the
number of interferometric fringes increased (the internal ‘chaotic’ area was fi lled with fringes too) and later on
it decreased. The radii of the ball-like structures were mostly increasing during their existence. The maximum
electron density reached the value of 1024 to 1025 m–3. The ball-like structures decayed by absorption inside the
expanded pinch column and/or gradually expired in rare plasma outside of the dense plasma column
Temporal distribution of linear densities of the plasma column in a plasma focus discharge
Experiments were carried out on the PF-1000 plasma focus device, with a deuterium filling and with
deuterium puffing from a gas-puff nozzle placed on the axis of the anode face. The current was reaching 2 MA.
15 interferometric frames from one shot were recorded with a Nd:YLF laser and a Mach–Zehnder interferometer,
with 10–20 ns delay between the frames. As a result, the temporal and spatial distribution of the linear densities
and the radial and axial velocities of the moving of plasma in the dense plasma column could be estimated