MICROWAVE PLASMA SOURCE FOR THE NEGATIVE HYDROGEN-ION PRODUCTION

Microwave plasma source for the negative hydrogen ion production was c onstructed and tested. The plasma source consists of two chambers: a p lasma production chamber and a plasma confinement chamber. The product ion chamber is placed into the strong axial magnetic held and the micr owaves (2.45 GHz, up to 5 kW) are introduced through the quartz window along the magnetic field lines. It is found that the suppression of t he fast electron loss to the window bolder is important to improve the efficiency of hydrogen plasma production. The plasma density increase s with the magnetic field strength in the plasma production chamber. F or the microwave power of 4 kW the uniform plasma of 3x1012 cm-3 for a rgon and 3x1011 cm-3 for hydrogen is obtained in the area of 20 x20 cm . Electron temperature in the plasma grid region is around 2 eV. The o ptimum gas pressure is around 6 mTorr. (C) 1998 American Institute of Physics.