The unit was proposed by R. Graham Cooks and Alan L. Rockwood[1] naming it in honour of J. J. Thomson who measured the mass-to-charge ratio of electrons and ions.
[2] The journal Rapid Communications in Mass Spectrometry (in which the original article appeared) states that "the thomson (Th) may be used for such purposes as a unit of mass-to-charge ratio although it is not currently approved by IUPAP or IUPAC.
"[7] Even so, the term has been called "controversial" by RCM's former Editor-in Chief[8] (in a review the Hoffman text cited above[2]).
[9] However, the editor-in-chief of the Journal of the Mass Spectrometry Society of Japan has written an editorial in support of the thomson unit.
Since 2013, the thomson is deprecated by IUPAC (Definitions of Terms Relating to Mass Spectrometry).