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Experiments in hydrogen have been developed in an ultra miniature device for pinch discharges (nanofocus NF: 5nF, 5–10kV, 5–10kA, 60–250 mJ, 16 ns time to peak current). Sub-millimetric anode radii covered by coaxial insulators were used in the experiments. Evidence of pinch was observed in electrical signals in discharges operating at ∼100 mJ. A single-frame image converter camera (4 ns exposure) was used to obtain plasma images in the visible range. The dynamic observed from the photographs is consistent with a dynamic observed in conventional plasma focus discharges. In this article evidence of X-rays emission from this ultraminiature pinch plasma focus device that operates at only 100mJ per shot is shown. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Measurement of anisotropy and neutron energy of the very small device PF-400J (880 nF, 30 kV, 120 kA, 400 J, 300 ns time to peak current, dI/dt∼4×1011 A/s) are presented. Neutron emission with the device operating in deuterium has been obtained and the maximum total neutron yield measured is of the order of 106 per shot at 9mbar. The following diagnostics have been applied: time of flight (TOF) to estimate the neutron mean energy, and angular distribution of the neutron emission using CR-39 nuclear track detectors covered with polyethylene located at several positions (between -90° to 90°). Discharges were performed at different pressures, 5–12 mbar, with a charging voltage of 30±2 KV (∼400J). With the results of the TOF measurements a mean neutron energy of (2.4±0.4) MeV was obtained. The angular measurements are compared with the total neutron yield (integral of the angular measurements). The results are consistent with an angular uniform plateau (isotropic emission) plus a shape peaked in the direction of the axis of the discharge (anisotropic emission). Isotropic components accounts for 57.5% of the accumulative emission, while the anisotropy component accounts for the remaining 42.5%. Anisotropic component appears between +50° and -50° approximately. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

In a new stage of characterization of our plasma focus devices of hundred and tens of joules, (PF-400J and PF-50J), preliminary series of measurements on soft X-ray and ion beams have been performed in the device PF-400J (176-539 J, 880 nF, T/4 ∼300 ns). The device was operated in hydrogen to 7 mbar of pressure . The temporal and spatial X-ray characteristics are investigated by means filtered PIN diodes and a multipinhole camera. Graphite collectors, operating in the bias ion collector mode, are used to estimate the characteristic ion energy using the time flight across the probe array. The time of the ion beam emission to be correlated with plasma emission events associated with the soft X-ray pulses detected by the probes. Temporal correlations between soft X-ray signals and ion beams are performed. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

It is known that there are plasma parameters that remain relatively constant for plasma focus facilities operating in a wide range of de energy, from 1kJ to 1MJ, such as: electron density, temperature and plasma energy density. Particularly the electron density is of the order of 1025m-3. Recently the experimental studies in plasma focus has been extended to devices operating under 1kJ, in the range of hundreds and tens of joules. In this work an optical refractive system was implemented in order to measure the electron density in a plasma focus devices of hundred of joules, PF-400J (880 nF, 30 kV, 120 kA, 400 J, 300 ns time to peak current, dI/dt∼4×1011 A/s. The plasma discharge was synchronized with a pulsed Nd-YAG laser (∼6ns FWHM at 532nm) in order to obtain optical diagnostics as interferometry and Schlieren. An electron density of (0.9±0.25)×1025m-3 was obtained at the axis of the plasma column close to the pinch time. This value is of the same order that the obtained in devices oparating in the energy range of 1kJ to 1MJ. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]