3 MV Pelletron Accelerator.
A 3MV Pelletron accelerator system has been recently added, to serve our users for high energy ion beam irradiation experiments. The complete system, which is 15.7 m long, has three major sections: (1) the ion sources, (2) the actual ion beam accelerator (made by NEC, http://www.pelletron.com/) including the quadrupole focusing unit the high energy magnet that could deliver beams to 5 separate beamlines and, (3) the beamlines (to date two lines have been built and two more are in the queue). The instrument is capable of delivering a focused beam with 2 mm FWHM; this beam could be raster-scanned, over an area of 20 mm by 20 mm. The ion beam can also be defocussed to cover a uniform area of about around 10mm/10 mm. This Pelletron accelerator is capable of accelerating a variety of ion species and multiple ion states. The principle of operation of this type of accelerator is simple. Negative ion beams are injected into the accelerator low energy tube; once inside the terminal (the portion between the low energy and high energy tubes), the negative ions enter an area rich in nitrogen where the extra electron plus one or more electrons are stripped off generating positive ions; these ions are accelerated through the second tube to be delivered at the exit of the accelerator. The maximum terminal voltage is 3MV.
Specifications of the Pelletron:
Ion types: ions from gases and sputtered materials Ion energy range: > 1 MeV to 6MeV for protons
2 to 9 MeV for Fe++, Si++, Ion current range: >50 uA for protons, >200 nA for Fe++ Target chamber vacuum: 10 -8 Torr range or better
Sample temperature control: RT to 600°C
Sample Handling: rapid interchange device
Capabilities: ion implantation, ion beam mixing, radiation damage