Electron and ion beam dynamics of the PF-1000 facility were investigated for the first time at its upper energy limit (≈1 MJ) in relation to neutron emission, the pinch's plasma ('target') characteristics and some other parameters with the help of a number of diagnostics with ns temporal resolution. Special attention was paid to the temporal and the spatial cross correlations of different phenomena. Results of these experiments are in favour of a neutron emission model based on ion beam-plasma interaction with three important features: (1) the plasma target is hot and confined during a few 'inertial confinement times'; (2) the ions of the main part of the beam are magnetized and entrapped around the pinch plasma target for a period longer than the characteristic time of the plasma inductive storage system and (3) ion-ion collisions (both fusion collisions, due to head-on impacts and Coulomb collisions) are responsible for neutron emission. Analysis has shown that one of the ways for achieving a future improvement in the neutron yield of the PF-1000 facility may by changing the geometry of the device. It may ensure an increase in both the discharge current and the initial working gas pressure, eventually resulting in the neutron yield boost.

This paper (paper I) presents the first part of results obtained with the PF-1000 facility for the first time at its upper energy limit (≈1 MJ). Special attention is paid here to plasma (‘pinch’) dynamics, which was investigated in relation to its electro-technical and radiation (especially neutron) characteristics with the help of a number of diagnostics, both time-integrated and with nanosecond temporal resolution. In these methods we utilized a Rogowski coil for the routine electro-technical measurements, visual multi-frame and streak cameras, soft x-ray pin-hole multi-frame cameras, PIN-diode assembly and PM tubes with scintillators for soft and hard x-rays as well as for neutron investigations together with a set of activation counters. In particular, the temporal cross correlation of different phenomena taking place during the discharge was investigated. The pinch's longevity appears to be 10–15 times larger than the ideal magnetohydrodynamic growth time (ratio of the pinch radius to the ion thermal velocity). It is demonstrated how the ‘target’ dynamics (pinch plasma of the dense plasma focus (DPF)) depends on and may be controlled by the electrode's size and the geometry of the chamber in this large-scale device. Diffraction of a shock wave together with a current sheath on an obstacle made at the DPF anode cap opens an opportunity for an inertial electrode to be used in future at larger DPF devices.

Basic operational characteristics of the plasma focus are considered from design perspectives to develop powerful radiation sources. Using these ideas we have developed two compact plasma focus (CPF) devices operating in neon with high performance and high repetition rate capacity for use as an intense soft X-ray (SXR) source for microelectronics lithography. The NX1 is a four-module system with a peak current of 320 kA when the capacitor bank (7.8 F 2 4) is charged to 14 kV. It produces 100 J of SXR per shot (4% wall plug efficiency) giving at 3 Hz, 300 W of average SXR power into 4. The NX2 is also a four-module system. Each module uses a rail gap switching 12 capacitors each with a capacity of 0.6 F. The NX2 operates with peak currents of 400 kA at 11.5 kV into watercooled electrodes at repetition rates up to 16 Hz to produce 300 W SXR in burst durations of several minutes. SXR lithographs are taken from both machines to demonstrate that sufficient SXR flux is generated for an exposure with only 300 shots. In addition, flash electron lithographs are also obtained requiring only ten shots per exposure. Such high performance compact machines may be improved to yield over 1 kW of SXR, enabling sufficient exposure throughput to be of interest to the wafer industry. In deuterium the neutron yield could be over 10 10 neutrons per second over prolonged bursts of minutes.

Interaction of deuterium plasma of streams and shock-waves (velocities up to 5 × 10 7 cm s −1 ) and fast ion beams (50-150 keV) generated in a dense plasma focus (DPF) device with low-activated austenitic steel, 25Cr12Mn20W, and ferritic steel, 10Cr9W, specimens positioned in the cathode part of DPF chamber has been investigated. If the power flux density of both types of irradiation is about q = 10 5 -10 7 W cm −2 , then ion implantation into a surface layer of the materials was observed. An increase of this parameter till q = 10 7 -10 8 W cm −2 results in the so-called 'detachment' effect (screening of the specimen surface by a cold plasma cloud). When the power flux density is increased up to q = 10 9 -10 10 W cm −2 , the evaporated plasma cloud becomes of the same temperature as the plasma of the shock-wave, and melting and evaporation of material from the specimen surface appears to be very strong, thus the so-called 'broken-implantation' takes place.

A source of soft X-ray emission based on the miniature 15 kJ (9È14 Ó) plasma focus was developed and tested. The X-ray emission was channelled along the chamber axis through an opening in the inner electrode (anode). A regime with a mean output of more than 100 J per discharge was found. At a discharge current of 280 kA and repetition rate of 3.5 Hz achieved by the device, its lifetime was estimated to be 107 commutations (about a year of continuous operation). A demonstration experiment on irradiation of an X-ray resist is discussed.

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