Means for measuring plasma density by resonant charge transfer with a beam of neutral particles

Claim 1

APPARATUS FOR MEASURING THE ION DENSITY OF MAGNETICALLY CONFINED PLASMA HAVING AN ION DENSITY OF FROM 1013 TO 1015 FIRST IONS PER CUBIC CENTIMETER, COMPRISING ION SOURCE MEANS FOR PRODUCING A PULSED BEAM OF H1+, H2+ AND H3+ SECOND IONS, NEUTRALIZING CELL MEANS ACTING ON SAID SECOND IONS TO PROVIDE AND DIRECT AN ATOMIC BEAM CONSISTING OF NEUTRAL PARTICLES THROUGH SAID PLASMA, STRIPPING CELL MEANS FOR CHARGING THE NEUTRAL PARTICLES PASSING THROUGH SAID PLASMA, MAGNETIC MEANS FOR DEFLECTING THE PARTICLES CHARGED IN SAID STRIPPING CELL MEANS, MEANS PRODUCING SECONDARY ELECTRONS FROM THE PARTICLES DEFLECTED BY SAID MAGNETIC MEANS, AND PHOTOMULTIPLIER MEANS FOR DETECTING SAID SECONDARY ELECTRONS FOR DETERMINING THE ATTENUATION OF THE ATOMIC BEAM PARTICLES DIRECTED ACROSS THE PLASMA, THE ATOMIC BEAM RESONANTLY TRANSFERRING CHARGES BETWEEN SAID FIRST IONS OF SAID PLASMA AND SAID ATOMIC BEAM PARTICLES THEREBY TO ATTENUATE THE PARTICLES IN SAID ATOMIC BEAM AN AMOUNT CORRESPONDING TO THE ION DENSITY OF SAID PLASMA WHEREBY SAID PLASMA DENSITY IS DETERMINED WITH SAID PHOTOMULTIPLIER MEANS.