G. I. Dimov

A powerful injector of neutrals with a surface-plasma source of negative ions

The operation of surface plasma sources for negative ion beams is described. A diagram shows the dependence of the H/sup -/ current density inside the emission slit on the discharge current under optimized conditions with a plasma layer thickness of 0.5 mm. Various parameters of the source are discussed. (MOW)

Ion sources at the Novosibirsk Institute of Nuclear Physics (invited)

A review of investigations in the physics and technology of ion sources, developed in the Institute of Nuclear Physics in Novosibirsk is presented. Distinctive features of physical processes and technical characteristics of plasma sources of gaseous ions, negative ion surface‐plasma sources, electrohydrodynamic (liquid metal) ion sources are considered. In original design plasma sources, ion beams with a current of up to 90 A and energies 1–30 keV are formed by four‐electrode multislit extraction systems from highly ionized, high brightness plasma flux, generated by an high‐current arc discharge with a cold cathode in a small cross‐section diaphragmed channel, and directed with a magnetic field of a special configuration. Plasma jet expansion for a very low ion temperature (0.1 eV) production is used. In surface plasma sources, the fluxes of negative ions are produced when electrons are captured from the electrode surface at the electron affinity level of sputtered and reflected particles. A discharge of ...

Development of a negative ion-based neutral beam injector in Novosibirska)

A 1000 keV, 5 MW, 1000 s neutral beam injector based on negative ions is being developed in the Budker Institute of Nuclear Physics, Novosibirsk in collaboration with Tri Alpha Energy, Inc. The innovative design of the injector features the spatially separated ion source and an electrostatic accelerator. Plasma or photon neutralizer and energy recuperation of the remaining ion species is employed in the injector to provide an overall energy efficiency of the system as high as 80%. A test stand for the beam acceleration is now under construction. A prototype of the negative ion beam source has been fabricated and installed at the test stand. The prototype ion source is designed to produce 120 keV, 1.5 A beam.

Hall current layer formation in arc discharge across magnetic field and transfer of fast ions out of discharge

In the work presented here the geometry of the Hall current layer in a plasma of the vacuum arc discharge in the transverse magnetic field are analyzed. The extraction of an intense pure flux of fast ions generated in the cathode spots with the help of the Hall layer is discussed. Experiments on the arc source of carbon fast ions are described. The anode geometry adequate to the mechanism of the arc current passage through the transverse magnetic field is found out experimentally. Up to 70% of fast ions are extracted out of the arc discharge in the arched magnetic field. In experiments, the Hall current layer formation in the vacuum arc discharge across magnetic field is confidently confirmed.

Tandem Accelerator with Vacuum Insulation for Boron-Neutron-Capture Therapy and Detection of Explosives by Resonance Absorption of γ-Rays

The status of the design work on an electrostatic tandem-accelerator with vacuum insulation for 2.5 MeV protons and up to 40 mA constant current is reported. This machine is to be used for solving problems of neutron therapy and the detection of explosives by nuclear-resonance absorption of γ-rays.

Production and Study of a High-Temperature Plasma in the Central Solenoid of the AMBAL-M Device

Results are presented from experiments on the production and study of a hot dense plasma in the central solenoid of the AMBAL-M fully axisymmetric ambipolar magnetic confinement system. The hot plasma in the solenoid and end cell is produced by filling the system with a thermally insulated current-carrying plasma stream with developed low-frequency turbulence. The plasma stream is generated by a gas-discharge plasma source placed upstream from the magnetic mirror of the solenoid. As a result, an MHD-stabilized plasma with a length of 6 m, a diameter of 40 cm, a density of 2×1013 cm−3, an ion energy of 250 eV, and an electron temperature of 60 eV is produced in the central solenoid. It is found that, in the quiescent decay phase, transverse plasma losses from the solenoid due to low-frequency oscillations and nonambipolar transport are rather small and comparable with the classical diffusion losses.

Development of a negative ion-based neutral beam injector in Novosibirsk

The negative-ion based injector of a hydrogen neutral beam with the energy up to 1 MeV is being developed in the Budker Institute. In order to provide high energy efficiency, the injector will employ a plasma (or photon) beam neutralization target and electrostatic beam energy recuperators. The design of the injector components is in progress. The experimental test facility for acceleration of a 1.5-Ampere hydrogen negative ion beam to the energy of 120 keV is under construction.