Radio-frequency spark source

Figure 3. Radio Frequency Spark Source. Reproduced with permission from Ref. 11 Copyright 1965 Interscience Publishers.

Figure 7.2. Schematic of a radio-frequency spark source.

Spark Source Mass Spectrometry (SSMS) is a method of trace level analysis—less than 1 part per million atomic (ppma)—in which a solid material, in the form of two conducting electrodes, is vaporized and ionized by a high-voltage radio frequency spark in vacuum. The ions produced from the sample electrodes are accelerated into a mass spectrometer, separated according to their mass-to-charge ratio, and collected for qualitative identification and quantitative analysis. 

In spark sources, electrical discharges are used to desorb and ionize the analytes from solid samples [98]. As shown in Figure 1.42, this source consists of a vacuum chamber in which two electrodes are mounted. A pulsed 1 MHz radio-frequency (RF) voltage of several kilovolts is applied in short pulses across a small gap between these two electrodes and produces electrical discharges. If the sample is a metal it can serve as one of the two electrodes, otherwise it can be mixed with graphite and placed in a cup-shaped electrode. 

Spark source SSMS Radio-frequency electric spark Double-focusing... 

---