Vacuum spark

Although a number of studies have been made concerning the basic properties of the RF vacuum spark used for excitation, the discharge is typically erratic, producing a widely fluctuating signal for mass analysis. For this reason, the most widely used form of this instrumentation consists of a mass spectrometer of the... 

ECTFE No primer Limited vacuumability Spark Testing recommended... 

Two measurements [31,10] were conducted at a low-inductance vacuum spark plasma and a tokamak plasma respectively. In both cases only the w line was reported. The first study used a double Johann spectrograph and characteristic K lines were used for calibration [31]. The energy of the w was 5.20558(55) keV or a 105 ppm result The second study [10] used a tokamak plasma and claimed an uncertainty of 40 ppm. Close lying Lyman series lines were used for calibration so this was a relative measurement chain assuming one-electron QED. Shorter wavelength calibration lines and helium-like resonances were observed in second order diffraction suggesting the significant systematic shifts discussed above. The third study [11] was a relative measurement to the w line and, as such, can not be compared to absolute measurements. 

High-purity graphite powder for DC-arc mixtures, or for pressed pellets for spark analysis, is also analyzed and guaranteed by manufacturers. In spark methods, the sample (if conductive) is often one of the two electrodes, and only a counter electrode is needed. Graphite electrodes are common, but metal counter electrodes, especially silver (to permit determination of carbon), are routinely employed in vacuum spark analysis. 

There are several sources of X-rays such as a Coolidge tube, vacuum sparks, hot-dense fusion plasmas, synchrotron, pinch devices, muonic atoms, beam-foil interaction, stellar X-ray emitters, solar flares, etc. The X-rays originating from all these sources can be broadly categorized into main types (1) atomic inner shell transitions, (2) emission by free electrons, (3) X-rays from few electron systems. The basic spectroscopic aspects of the various types of X-rays are discussed in this article. 

The negative ions of all Pt group elements M have been mass spectrometrically detected using ionization (by a pulsed rf vacuum-spark discharge) of powders of Ru, Rh, Os, and Ir and of metals (or alloys) of Pd and Pt [1]. 

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