Abstract: A method of a navigational path includes enabling a user to successively display a plurality of web pages; maintaining a full breadcrumb path that includes a link to each of the previously displayed pages; displaying a shortened breadcrumb path on a current page, the shortened breadcrumb path including fewer links than the full breadcrumb path, and displaying the full breadcrumb path only upon request. A method of representing a current location within a hierarchical structure of a web site or web application includes maintaining a hierarchical map of the web site or web application; generating a web page that has a predetermined level within the hierarchical map; displaying a hierarchical structure selector on the web page, and when the displayed hierarchical structure selector is selected by a user, displaying an indication of the predetermined level and a link to each hierarchically higher level of the generated web page.

Abstract: In a quadrupole ion store or ion trap type mass spectometer, significantly improved mass selection is achieved by simultaneously trapping ions within the mass range of interest and then scanning the applied RF and DC voltages or the frequency .omega. to sequentially render unstable trapped ions of consecutive specific masses. These are passed out through apertures in an end cap to a high gain electron multiplier to provide a signal indicative of the ion mass. Sensitivity and mass resolution is also enhanced by operating the ion trap at a relatively high pressure in the range 1.times.10.sup.-1 to 1.times.10.sup.-5 torr. The presence of collision gas molecules, such as helium, improves sensitivity and mass resolution. In addition, the structure itself is built of stacked units, sealed by O-rings, which are easily disassembled for cleaning.

Abstract: An ionizer adapted to be placed in a vacuum envelope for providing ions of a sample to be analyzed is disclosed herein and includes an electron source, ion accelerating and focusing electrodes and an interchangeable ionization chamber including a first opening for allowing electrons to enter the chamber and an exit opening to allow ions to exit said chamber. The ionization chamber is supported in cooperative relationship with the electron source and accelerating and focusing electrodes whereby electrons enter the chamber through the first opening and form sample ions in the chamber which then exit the chamber through the exit opening toward said accelerating and focusing electrodes.