voltages and currents of the various ion source supplies. The readouts are displayed on digital LED meters. Digital cards are used to transmit "ON" and "OFF" signals to operate motors that control the autotransformers and mechanical source gas leak.
The system is easy to maintain. Each function has a specific card and fiber cable. If a failure occurs, the failed board is replaced and can be
fixed at a later time.
Liquid Cooling System- A number of components located in the high voltage terminal require liquid cooling. This is provided by a closed-loop demineralized water system located at ground potential and fed to the terminal through plastic lines. The system includes a room temperature water cooled heat exchanger, pump and demineralizer cartridge assembly. A flow switch and temperature sensor are incorporated into the safety interlock system. A manifold in the terminal directs the coolant to the various components.
The PS-250 has produced beams of ions varying from H to Ar over an energy range of 20 to 200 keV. Beam levels are 10's to 100's of microamps.
For use in materials analysis, a well collimated beam of heavy ions with a divergence less than 0.5 degrees has been produced with microampere level intensities.
The system has demonstrated its ability to ramp up from 0 to 220 keV in less than 5 seconds. Its generous electrostatic design leads to corona free
Typical operating vacuum at the base of the accelerator tube is 5x 1 0E-06 torr. Better vacuum is achievable at the target position by means of
differential pumping. With a second 250 l/s pump after a low conductance aperture, the vacuum at a target position has been measured in
the low 10E-07 range.
Radiation measurements made at the operator's console about five feet from the exit of the accelerator have indicated levels of less than 2 mR/hour for a 220 keV beam of Ar ions of total intensity greater than 20 microamps.
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