Parabola spectrograph

J.J. THOMSON constructs the first mass spectrometer (then called a parabola spectrograph) [16], He obtains mass spectra of O2, N2, CO, CO2 and COCI2. He observes negative and multiply charged ions. He discovers metastable ions. In 1913, he discovers isotopes 20 and 22 of neon. 

Most practitioners of the precise art and subtle science of mass spectrometry acknowledge the field to have originated with the work of J.J. Thomson (Fig. 19.1) and associates, [6] published in 1910-1912, using the parabola mass spectrograph. Seminal discoveries that he and his coworkers made include the fact that the elements could be polyisotopic, by discovering the isotopes of neon. Thomson was awarded the Nobel Prize in physics of 19062 for his work on investigations on the conduction of electricity by gases. ... 

Figure 1.5 Parabola mass spectrograph constructed bylJ. Thomson (1910) with a discharge tube as ion source, a superimposed electrical field and a magnetic field oriented parallel to it for ion separation, and a photoplate for ion detection. (H. Kienitz (ed.), Massenspektrometrie (1968), Verlag Chemie, Weinheim. Reproduced by permission of Wiley-VCH.)...

In several experiments Thomson also introduced molecules such as COCl2 and hydrocarbons into the discharge ion source of the parabola mass spectrograph and observed the formation of... 

The technique of mass spectrometry has been around for almost 100 years. Most practitioners target J. J. Thomson s 1910-1912 reports on his work with the parabola mass spectrograph as the origin. The field has evolved into a number of techniques— tools —that had significant utility initially, then either proved their worth over the long term as general purpose tools, settled into a particular niche application area, or faded entirely from view. 

In Figure 2 the parabola formed by the top and bottom branches on the left-hand side are due to neon. Under better resolution they show the presence of isotopes at masses 20 and 22. Isotopes had previously been observed in studies of radioactivity. Thomson encouraged a research student in the Cavendish Laboratory, FW Aston, to build a mass spectrograph for further studies of stable isotopes. The research was interrupted by the war of 1914-1918 and so the work was not published until 1923. 

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