All mass spectroscopes consist of a source, an analyzer, a detector, automatic recorders, and data-processing systems. This chapter discusses these five components. It also discusses the use of mass spectroscopes in various fields, such as in discovery of stable isotopes, isotopic abundances, in the measurement of atomic masses, nuclear studies, chemical analysis, and ionization and dissociation phenomena. Mass spectroscopes have helped in the discovery of stable isotopes, which occur by natural processes. Four new isotopes have been found, and a few others are suspected. Perhaps the most striking discovery was that of vanadium 50 by Hess and Inghram. Important and rapidly developing is the use of mass spectroscopes in the nuclear studies of all kinds. Many of these studies utilize it in a straightforward manner, as in the measurement of isotope abundances to determine neutron capture cross-sections. The mass spectroscope has been considered mandatory also for the investigation of ionization and dissociation phenomena by the electron impact method. In a typical experiment, a gas whose ionization potential is desired is placed in the electron impact source. The energy of the bombarding electrons is gradually increased until it is just enough to produce ions.

physica status solidi (a)Volume 131, Issue 1 p. 105-106 Original Paper Investigation of STM tips by FIM with cyclohexane as organic image gas U. Schmidt, U. Schmidt Institut für Physikale und Theoretische Chemie, Universität Bonn Search for more papers by this authorTh. Fries, Th. Fries Institut für Physikale und Theoretische Chemie, Universität Bonn Search for more papers by this authorF. W. Röllgen, F. W. Röllgen Institut für Physikale und Theoretische Chemie, Universität Bonn Search for more papers by this authorK. Wandelt, K. Wandelt Institut für Physikale und Theoretische Chemie, Universität Bonn Search for more papers by this author U. Schmidt, U. Schmidt Institut für Physikale und Theoretische Chemie, Universität Bonn Search for more papers by this authorTh. Fries, Th. Fries Institut für Physikale und Theoretische Chemie, Universität Bonn Search for more papers by this authorF. W. Röllgen, F. W. Röllgen Institut für Physikale und Theoretische Chemie, Universität Bonn Search for more papers by this authorK. Wandelt, K. Wandelt Institut für Physikale und Theoretische Chemie, Universität Bonn Search for more papers by this author First published: 16 May 1992 https://doi.org/10.1002/pssa.2211310118 Wegelerstr. 12, W-5300 Bonn 1, FRG. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat No abstract is available for this article. References 1 U. Schmidt, H. Rasch, Th. Fries, F. W. Röllgen, and K. Wandelt, Proc. 38th Internat. Field Emission Symp., Wien 1991, Google Scholar Surface Sci. 266, 249 (1992). 10.1016/0039-6028(92)91028-A CASWeb of Science®Google Scholar Volume131, Issue116 May 1992Pages 105-106 ReferencesRelatedInformation

In a previous paper, the observation of spontaneous desorption (SD) of negative ions in a time-of-flight mass spectrometer has been reported. The ion emission was found to depend on a high potential difference between the target and the ion accelerating grid placed a few mm apart from it. This paper shows that the SD of ions is a secondary ion emission phenomenon in which charged particles coming from the grid surface hit the target. The incident particles are either directly extracted from the grid by the applied high electric field and/or are secondary ions of impinging charged particles generated at the sample layer surface, again by a field-induced process. Measurements of the ion multiplicity suggest multiatomic ions as incident particles. The SD effect could also be established for positive ions.