INVESTIGATIONS OF A MAGNETICALLY ENHANCED GRIMM-TYPE GLOW-DISCHARGE SOURCE

The application of a magnetic field to the Grimm glow discharge lamp i n order to enhance its sputtering rate and emission characteristics fo r optical emission spectrometry was investigated. A Nd-Fe-B magnet was placed behind samples of copper and Monel 400 (a Cu-Ni-Fe alloy) havi ng thicknesses of 1.0-1.5 mm. The sputtering rates (at 1000 V in argon at 4 Torr) for copper could be increased from 100 to 200 mu g/min und er the influence of the magnetic field. The noise behavior of the atom ic emission was found to be influenced slightly by the application of the magnetic field. For the nonresonance Cu(I) line emission at 282.4 nm, an increase in intensity occurred in accordance with the increase in sputtering rate, whereas for resonance lines [Cu(I) 324.7 nm in the case of copper samples and Cr(I) 425.7 nm for Monel 400 containing 0. 06% (w:w) Cr], a drop in the atomic emission was found upon applicatio n of the magnetic field. This result is thought to be due to self-abso rption, which has been shown to occur in a Grimm-type glow discharge s ource.