A Study of the Quadrupole Ion Storage Source

Although the three-dimensional quadrupole ion trap has received some attention as a mass spectrometer, few reports have been published describing the more general exploitation of its ion storage capabilities« This latter aspect is the subject of the present research. Initially the general features of trapped ion techniques are surveyed in a review of the literature, after which the theory of the quadrupole ion storage trap (QUISTOR) is developed in general terms and a method for calculating the mean kinetic energy of stored ions derived. The design of the QUISTOR is briefly described and the method of mounting this device as an ion source for a commercial quadrupole mass filter given in detail« Various modifications made to the remainder of other existing equipment are also described« Following this the performance is presented in two parts« Firstly, an account of the modes of operation and the details of a characterization of the electron optics and the storage capabilities is given, and secondly, the various types of ionic process that have been observed in the QUISTOR, including low-pressure Chemical Ionization employing air as a reagent gas, are detailed« It is shown that the QUISTOR is an extremely versatile device, being capable of operation in a manner akin to a normal ion source or as an ion storage source, Finally, some suggestions for instrumental improvements and further research are included in a general discussion of the device.