General





























Description


The
Peabody Scientific Model PS-200DL is a dual leg ion beam system. Each ion  beam leg is independently controllable and both are focussed to a common point at the target. The system is capable of producing intense, high purity beams of light and heavy ions over a wide energy range. Energies range from 30 keV to a minimum of a few hundred electron volts. Ion beams can be focused to a few millimeters diameter or,
conversely, scanned to cover a large area at the target position. The operating characteristics make the system ideal for co-deposition, co-sputtering, co-implantation, compound thin film fabrication, etc.
         
The system is conservatively designed for reliable operation. Each leg consists of an ion source, extraction gap, Einzel lens, 30 degree electromagnetic mass analysis magnet, deceleration gap, electrostatic focus lens, steerer/deflection plates, vacuum system and all associated power supplies. Vacuum pumps are located at the ion source region and final lens positions.
         
Typical operation of the system is as follows. Ions are formed in the ion source and are extracted to an energy up to 30 keV by the extraction gap. The high brightness divergent beam is then focused by the Einzel lens through the 30 degree analyzing magnet to a mass resolving aperture at the deceleration gap. The beam is brought to its final energy at this gap. The beam, which is diverging as it exits the gap, is refocused by an              electrostatic lens to an appropriate size at the target position. For large target areas (1 cm), electrostatic deflection plates are provided to sweep the beam uniformly over the appropriate area.
         
The system design lends itself to differential pumping so that UHV conditions are available in the target area.
         
The system for the production of energetic light ions (H, He) and other gaseous species uses standard components including: Duoplasmatron Ion Source, Extraction Gap, Einzel Lens, 30 Degree Magnet, Deceleration Gap, Electrostatic Lens. The following is a detailed description:
         
Duoplasmatron Ion Source
         
The Duoplasmatron is a low pressure arc discharge source in which the gas to be ionized is electrostatically constricted by a funnel-shaped intermediate electrode placed between the filament and the anode. A strong axial magnetic field is developed between the intermediate electrode and the anode, which further constricts the discharge to a narrow plasma beam along the axis of the exit aperture.         

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